Systemic Approach to Differential Diagnosis

SECTION I. Cardiopulmonary Disorders

• Arrhythmias

• Arterial Thromboembolism

• Aspiration Pneumonia

• Atrioventricular Valve Disease, Chronic (Mitral or Tricuspid Valve)

• Cardiomegaly

• Chylothorax

• Congenital Heart Disease

• Heart Failure

• Heartworm Disease

• Hypertension

• Laryngeal and Pharyngeal Disease

• Lower Respiratory Tract Disease

• Mediastinal Disease

• Myocardial Diseases

• Murmurs

• Pericardial Effusion

• Pleural Effusion

• Pulmonary Disease

• Pulmonary Edema

• Pulmonary Thromboembolism

• Tachycardia, Sinus

Arrhythmias

Differential Diagnosis

Slow, Irregular Rhythms

• Sinus bradyarrhythmias

• Sinus arrest

• Sick sinus syndrome

• High-grade second-degree atrioventricular (AV) block

Slow, Regular Rhythms

• Sinus bradycardia

• Complete AV block with ventricular escape rhythm

• Atrial standstill with ventricular escape rhythm

Fast, Irregular Rhythms

• Atrial or supraventricular premature contractions

• Paroxysmal atrial or supraventricular tachycardia

• Atrial flutter

• Atrial fibrillation

• Ventricular premature contractions

• Paroxysmal ventricular tachycardia

Fast, Regular Rhythms

• Sinus tachycardia

• Sustained supraventricular tachycardia

• Sustained ventricular tachycardia

Normal, Irregular Rhythms (require no treatment)

• Respiratory sinus arrhythmia

• Wandering pacemaker

Arterial Thromboembolism

Clinical Findings

Acute Limb Paresis

• Posterior paresis (“saddle” thrombus: most common presentation)

• Monoparesis (right subclavian artery thrombus; second most common presentation in cats)

• Intermittent claudication

• Severe limb pain

• Cool distal limbs

• Cyanotic nail beds

• Arterial pulse absent

• Contracture of affected muscles

• Vocalization (pain, distress)

Renal Infarction

• Renal pain

• Acute renal failure

Splenic Infarction

• Lethargy

• Anorexia

• Vomiting

• Diarrhea

Mesenteric Infarction

• Abdominal pain

• Vomiting

• Diarrhea

Cerebral Infarction

• Neurologic deficits

• Seizures

• Sudden death

Signs of Heart Failure

• Systolic murmur

• Gallop rhythm

• Tachypnea/dyspnea

• Weakness/lethargy

• Anorexia

• Arrhythmias

• Hypothermia

• Cardiomegaly

• Effusions

• Pulmonary edema

Hematologic and Biochemical Abnormalities

• Azotemia

• Increased alanine aminotransferase activity

• Increased aspartate aminotransferase activity

• Increased lactate dehydrogenase activity

• Increased creatine kinase activity

• Hyperglycemia

• Lymphopenia

• Disseminated intravascular coagulation

Aspiration Pneumonia

Etiology of Aspiration Pneumonia

Esophageal Disorders

• Megaesophagus

• Reflux esophagitis

• Esophageal obstruction

• Myasthenia gravis (localized)

• Bronchoesophageal fistulae

Localized Oropharyngeal Disorders

• Cleft palate

• Cricopharyngeal motor dysfunction

• Laryngoplasty

• Brachycephalic airway syndrome

Systemic Neuromuscular Disorders

• Myasthenia gravis

• Polyneuropathy

• Polymyopathy

Decreased Mentation

• General anesthesia

• Sedation

• Post ictus

• Head trauma

• Severe metabolic disease

Iatrogenic

• Force-feeding

• Stomach tubes

Vomiting (in combination with other predisposing factors)

 

Atrioventricular Valve Disease, Chronic (Mitral or Tricuspid Valve)

Potential Complications

Acute Worsening of Pulmonary Edema

• Arrhythmias

  • •
    Frequent atrial premature contractions
  • •
    Paroxysmal atrial/supraventricular contractions
  • •
    Atrial fibrillation
  • •
    Ventricular tachyarrhythmias

• Ruptured chordae tendineae

• Iatrogenic volume overload

  • •
    Excessive fluid or blood administration
  • •
    High-sodium fluids

• High sodium intake

• Increased cardiac workload

  • •
    Physical exertion
  • •
    Anemia
  • •
    Infection/sepsis
  • •
    Hypertension
  • •
    Disease of other organ systems (pulmonary, hepatic, renal, endocrine)
  • •
    Environmental stress (heat, humidity, cold, etc.)

• Inadequate medication for stage of disease

• Erratic or improper drug administration

• Myocardial degeneration and poor contractility

Causes of Reduced Cardiac Output

• Arrhythmias

• Ruptured chordae tendineae

• Cough-related syncope

• Left atrial tear, intrapericardial bleeding, cardiac tamponade

• Secondary right-sided heart failure

• Myocardial degeneration, poor contractility

Cardiomegaly

Differential Diagnosis

Generalized Cardiomegaly

• Dilated cardiomyopathy

• Pericardial effusion

• Mitral and tricuspid valve insufficiency

• Tricuspid dysplasia

• Pericardioperitoneal diaphragmatic hernia

• Ventricular septal defect

• Patent ductus arteriosus

Left Atrial Enlargement

• Mitral valve insufficiency

• Hypertrophic cardiomyopathy

• Early dilated cardiomyopathy (especially in Doberman Pinschers)

• Subaortic or aortic stenosis

Left Atrial and Ventricular Enlargement

• Dilated cardiomyopathy

• Hypertrophic cardiomyopathy

• Mitral valve insufficiency

• Aortic valve insufficiency

• Ventricular septal defect

• Patent ductus arteriosus

• Subaortic or aortic stenosis

• Systemic hypertension

• Hyperthyroidism

Right Atrial and Ventricular Enlargement

• Advanced heartworm disease

• Chronic severe pulmonary disease

• Tricuspid valve insufficiency

• Atrial septal defect

• Pulmonic stenosis

• Tetralogy of Fallot

• Reversed-shunting congenital defects

• Pulmonary hypertension

• Mass lesion within right heart

Chylothorax

Diagnostic Criteria

• Protein concentration is greater than 2.5 g/dL

• Nucleated cell count ranges from 400 to 10,000/μL

• Predominant cell type on cytology is the small lymphocyte (also see neutrophils, macrophages, plasma cells, and mesothelial cells)

• Triglyceride concentration of pleural fluid is greater than that of serum (definitive test)

Causes of Chylothorax

Traumatic

• •Blunt force trauma (e.g., vehicular trauma)
• •Postthoracotomy

Nontraumatic

• •Neoplasia (especially mediastinal lymphoma in cats)
• •Cardiomyopathy
• •Dirofilariasis
• •Pericardial disease
• •Other causes of right heart failure
• •Lung lobe torsion
• •Diaphragmatic hernia
• •Systemic lymphangiectasia

Idiopathic (most commonly diagnosed)

 

Diagnostic Tests to Identify Underlying Cause of Chylothorax in Dogs and Cats

CBC, Serum Chemistry, Urinalysis

• •Evaluation of systemic status

Cytologic Examination of Pleural Fluid

• •Infectious agents
• •Neoplastic cells

Thoracic Radiographs (after fluid removal)

• •Cranial mediastinal masses
• •Other neoplasia
• •Cardiac disease
• •Heartworm disease
• •Pericardial disease

Ultrasonography (before fluid removal)

• •Cranial mediastinum (masses)
• •Echocardiography (cardiomyopathy, heartworm disease, pericardial disease, congenital heart disease)
• •Ultrasound of body wall and pleural space (neoplasia, lung lobe torsion)

Heartworm Antibody and Antigen Tests

• •Heartworm disease

Lymphangiography

• •Preoperative and postoperative assessment of thoracic duct

Congenital Heart Disease

Breed Predispositions

Patent Ductus Arteriosus

• Maltese, Pomeranian, Shetland Sheepdog, English Cocker Spaniel, English Springer Spaniel, Keeshond, Bichon Frise, toy and miniature Poodle, Yorkshire Terrier, Collie, Cocker Spaniel, German Shepherd, Chihuahua, Kerry Blue Terrier, Labrador Retriever, Newfoundland; female affected more than male

Subaortic Stenosis

• Newfoundland, Golden Retriever, Rottweiler, Boxer, German Shepherd, English Bulldog, Great Dane, German Shorthaired Pointer, Bouvier des Flandres, Samoyed

Aortic Stenosis

• Bull Terrier

Pulmonic Stenosis

• English Bulldog (male affected more than female), Mastiff, Samoyed, Miniature Schnauzer, Newfoundland, West Highland White Terrier, Cocker Spaniel, Beagle, Basset Hound, Airedale Terrier, Boykin Spaniel, Chihuahua, Scottish Terrier, Boxer, Fox Terrier, Chow Chow, Labrador Retriever, Schnauzer

Atrial Septal Defect

• Samoyed, Doberman Pinscher, Boxer

Ventricular Septal Defect

• English Bulldog, English Springer Spaniel, Keeshond, West Highland White Terrier, cats

Tricuspid Dysplasia

• Labrador Retriever, German Shepherd, Boxer, Weimaraner, Great Dane, Old English Sheepdog, Golden Retriever, various other large breeds

Mitral Dysplasia

• Bull Terrier, German Shepherd, Great Dane, Golden Retriever, Newfoundland, Mastiff, Rottweiler, cats

Tetralogy of Fallot

• Keeshond, English Bulldog

Persistent Right Aortic Arch

• German Shepherd, Great Dane, Irish Setter

Cor Triatriatum

• Medium- to large-breed dogs (Chow Chow), rarely small-breed dogs or cats

Peritoneopericardial Diaphragmatic Hernia

• Weimaraner

Heart Failure

Causes of Chronic Heart Failure

Left-Sided Heart Failure

Volume-Flow Overload

• Mitral valve regurgitation (degenerative, congenital, infective)

• Aortic regurgitation (infective endocardiosis, congenital)

• Ventricular septal defect

• Patent ductus arteriosis

Myocardial Failure

• Myocardial ischemia/infarction

• Drug toxicity (e.g., doxorubicin)

Pressure Overload

• Aortic/subaortic stenosis

• Systemic hypertension

Restriction of Ventricular Filling

• Hypertrophic cardiomyopathy

• Restrictive cardiomyopathy

Left- or Right-Sided Heart Failure

Myocardial Failure

• Idiopathic dilated cardiomyopathy

• Infective myocarditis

Volume-Flow Overload

• Chronic anemia

• Thyrotoxicosis

Right-Sided Heart Failure

Volume-Flow Overload

• Tricuspid endocarditis

• Tricuspid endocardiosis

• Tricuspid dysplasia

Pressure Overload

• Pulmonic stenosis

• Heartworm disease

• Pulmonary hypertension

Restriction to Ventricular Filling

• Cardiac tamponade

• Constrictive pericardial disease

Severity

Classification Systems

New York Heart Association Functional Classification

• Class I: Heart disease present, but no evidence of heart failure or exercise intolerance; cardiomegaly minimal to absent

• Class II: Signs of heart disease with evidence of exercise intolerance; radiographic cardiomegaly present

• Class III: Signs of heart failure with normal activity or signs at night (e.g., cough, orthopnea); radiographic signs of significant cardiomegaly and pulmonary edema or pleural/abdominal effusion

• Class IV: Severe heart failure with clinical signs at rest or with minimal activity; marked radiographic signs of congestive heart failure (CHF) and cardiomegaly

Forrester Classification

• Class I: Normal cardiac output and pulmonary venous pressure

• Class II: Pulmonary congestion but normal cardiac output

• Class III: Low cardiac output and peripheral hypoperfusion with no pulmonary congestion

• Class IV: Low cardiac output with pulmonary congestion

Clinical Findings

Low-Output Signs

• Exercise intolerance

• Syncope

• Weak arterial pulses

• Tachycardia

• Arrhythmias

• Cold extremities

• Prerenal azotemia

• Cyanosis

Signs Related to Poor Skeletal Muscle Function

• Weight loss

• Exercise intolerance

• Dyspnea

• Decreased muscle mass

Signs Related to Fluid Retention

Left-Sided Heart Failure (Pulmonary Edema)

• Dyspnea/orthopnea

• Exercise intolerance

• Wet lung sounds

• Tachypnea

• Gallop rhythm

• Functional mitral regurgitation

• Cyanosis

• Cough

Right-Sided Heart Failure

• Ascites

• Subcutaneous edema

• Jugular distension/pulsation

• Hepatomegaly

• Splenomegaly

• Hepatojugular reflux

• Gallop rhythm

• Cardiac arrhythmias

Bilateral Signs

• Pleural effusion (dyspnea, muffled heart sounds, cough)

Heartworm Disease

Clinical Findings

Historical Findings

• Asymptomatic

• Cough

• Dyspnea

• Weight loss

• Lethargy

• Exercise intolerance

• Poor condition

• Syncope

• Abdominal distension (ascites)

Physical Findings

• Weight loss

• Right-sided murmur (tricuspid insufficiency)

• Split-second heart sound

• Gallop rhythm

• Cough

• Pulmonary crackles

• Dyspnea

• Muffled breath sounds

• Cyanosis

• Right-sided heart failure

  • •
    Jugular distension/pulsation
  • •
    Hepatosplenomegaly
  • •
    Ascites
• Pulmonary thromboembolism

  • •
    Dyspnea/tachypnea
  • •
    Fever
  • •
    Hemoptysis

• Cardiac arrhythmias/conduction disturbances (rare)

• Caval syndrome

  • •
    Hemoglobinuria
  • •
    Anemia
  • •
    Disseminated intravascular coagulation (DIC)
  • •
    Icterus
  • •
    Collapse/death

Clinicopathologic Findings

• Eosinophilia

• Nonregenerative anemia

• Neutrophilia

• Basophilia

• Proteinuria

• Hyperbilirubinemia

• Azotemia

• Thrombocytopenia

Radiographic Signs

• Right ventricular enlargement

• Prominent main pulmonary artery segment

• Increased pulmonary artery size

• Tortuous pulmonary vessels

• Caudal vena cava enlargement

• Hepatosplenomegaly

• Ascites

• Pleural effusion

• Bronchial/interstitial lung disease

Diagnosis in Dogs

Antigen Test Positive and Modified Knott's or Filter Test Negative

• •Perform complete blood count, serum chemistry panel, urinalysis, thoracic radiography
• •Start preventative and adulticidal therapy
• • Antigen test positive and Modified Knott's or filter test positive
• •Perform complete blood count, serum chemistry panel, urinalysis, and thoracic radiography
• •Start “slow kill” macrolide and adulticidal therapy

Antigen Test Negative

• •No infection or low heartworm burden
• •Start preventative

Hypertension

Pulmonary Hypertension

Potential Clinical Signs

• Ascites

• Jugular venous distension/pulsation

• Subcutaneous edema

• Cachexia

• Nonspecific respiratory signs

  • •
    Coughing
  • •
    Tachypnea
  • •
    Respiratory distress
  • •
    Increased bronchovesicular sounds
  • •
    Hemoptysis
• Cyanosis

  • •
    Right-to-left cardiac shunts
  • •
    Severe respiratory disease

• Split or loud pulmonic component to second heart sound

• Right or left apical systolic murmurs (tricuspid or mitral regurgitation)

Radiographic Signs

• Cardiomegaly

• Right ventricular enlargement

• Dilated central pulmonary arteries with tapering toward periphery

• Eisenmenger complex (pulmonary undercirculation and right-sided heart enlargement)

• Left atrial enlargement and perihilar to caudodorsal pulmonary infiltrates (left-sided congestive heart failure)

Echocardiographic Signs

• Right ventricular concentric hypertrophy and dilation

• Main pulmonary artery and main branch dilation

• Systolic flattening of interventricular septum

• Paradoxical septal motion

• Reduced left ventricular dimensions in severe pulmonary hypertension caused by ventricular underfilling

Laboratory Values

• Acidosis

• Rule out heartworm disease

Systemic Hypertension

Causes of Systemic Hypertension in Dogs and Cats

• Renal failure (chronic or acute)

• Hyperadrenocorticism

• Diabetes mellitus

• Pheochromocytoma

• Hyperthyroidism

• Liver disease

• Hyperaldosteronism

• Intracranial lesions (↑ intracranial pressure)

• High-salt diet

• Obesity

• Chronic anemia (cats)

Clinical Signs of Systemic Hypertension

Ocular Findings

• Hypertensive choroidopathy (edema, vascular tortuosity, hemorrhage, focal ischemia)

• Hypertensive retinopathy (edema, vascular tortuosity, hemorrhage, focal ischemia, atrophy)

• Intraocular hemorrhage (retinal, vitreal, hyphema)

• Papilledema

• Blindness

• Glaucoma

• Secondary corneal ulcers

Neurologic Findings

• Edema (↑ intracranial pressure)

• Hypertensive encephalopathy (lethargy, behavioral changes)

• Cerebrovascular accident (focal ischemia, hemorrhage)

• Seizures/collapse

Renal

• Polyuria/polydipsia

• Glomerulosclerosis/proliferative glomerulitis

• Renal tubular degenerative and fibrosis

• Further deterioration in renal function

Cardiac

• Left ventricular hypertrophy

• Murmur or gallop sound

• Aortic dilation

• Aneurysm or dissection rare

Other

• Epistaxis

Laryngeal and Pharyngeal Disease

Differential Diagnosis

• Laryngeal paralysis

• Brachycephalic airway syndrome

• Acute laryngitis

• Laryngeal neoplasia

• Nasopharyngeal polyp

• Abscess

• Tonsillitis

• Pharyngitis

• Obstructive laryngitis

• Laryngeal collapse

• Trauma

• Foreign body

• Extraluminal mass

• Elongated soft palate

• Cleft palate

• Soft palate hypoplasia

• Pharyngeal neoplasia

• Granuloma

• Pharyngeal mucoceles

• Web formation

• Nasopharyngeal stenosis

Causes of Laryngeal Paralysis

Idiopathic

 

Polyneuropathy and Polymyopathy

• Idiopathic

• Immune-mediated

• Endocrinopathy

  • •
    Hypothyroidism
  • •
    Hypoadrenocorticism

• Toxicity

• Congenital disease

Ventral Cervical Lesion

• Nerve trauma

  • •
    Direct trauma
  • •
    Inflammation
  • •
    Fibrosis

• Neoplasia

• Other inflammatory or mass lesion

Anterior Thoracic Lesion

• Neoplasia

• Trauma

  • •
    Postoperative
  • •
    Other

• Other inflammatory or mass lesion

Myasthenia Gravis

 

Lower Respiratory Tract Disease

Differential Diagnosis

Disorders of Trachea and Bronchi

• Canine infectious tracheobronchitis

• Collapsing trachea

• Bacterial infection

• Mycoplasmal infection

• Bronchial asthma

• Neoplasia

• Allergic bronchitis

• Feline bronchitis

• Bronchial compression

  • •
    Left atrial enlargement
  • •
    Hilar lymphadenopathy

• Acute bronchitis

• Canine chronic bronchitis/bronchiectasis

• Parasites (Oslerus osleri, Filaroides osleri)

• Tracheal tear

• Primary ciliary dyskinesia

• Airway foreign body

• Chronic aspiration

Disorders of Pulmonary Parenchyma

• Infectious disease

  • •
    Viral pneumonia (canine influenza, canine distemper virus, canine adenovirus, canine parainfluenza, feline calicivirus, feline infectious peritonitis, pneumonia secondary to feline leukemia virus or feline immunodeficiency virus)
  • •
    Bacterial pneumonia
  • •
    Protozoal pneumonia (toxoplasmosis)
  • •
    Fungal pneumonia (blastomycosis, histoplasmosis, coccidioidomycosis)
  • •
    Rickettsial disease (Rickettsia rickettsii, Ehrlichia spp.)
  • •
    Parasitism

    • •
      Heartworm disease
    • •
      Pulmonary parasites (Paragonimus, Aelurostrongylus, Capillaria, Crenosoma spp.)
    • •
      Larval migration of Toxocara canis

• Aspiration pneumonia

• Pulmonary infiltrates with eosinophils

• Eosinophilic pulmonary granulomatosis

• Aspiration pneumonia

• Pulmonary neoplasia (primary, metastatic, lymphosarcoma, lymphomatoid granulomatosis, malignant histiocytosis)

• Pulmonary hypertension

• Pulmonary contusions

• Pulmonary thromboembolism

• Pulmonary edema

• Acute respiratory distress syndrome

• Lung lobe torsion

• Pulmonary fibrosis

• Pickwickian syndrome (obesity)

• Idiopathic interstitial pneumonias

Mediastinal Disease

Differential Diagnosis of Lesions Associated with Focal Mediastinal Enlargement

• Pneumomediastinum

• Mediastinitis (Histoplasma, Cryptococcus, Actinomyces, Nocardia, Spirocerca spp.)

• Mediastinal hemorrhage

• Mediastinal cysts

• Nonneoplastic mediastinal masses (fungal pyogranulomas, abscesses, granulomas, lymphadenopathy, hematomas)

• Mediastinal neoplasia (lymphosarcoma)

• Thymoma

• Obesity

• Thymic hemorrhage

• Heart base mass

• Neurogenic tumor

• Tracheal mass

• Esophageal mass, foreign body, or dilatation

• Ectopic thyroid tissue

• Mediastinal edema

• Vascular mass (aorta, cranial vena cava)

• Paraspinal or spinal mass

• Aortic stenosis

• Patent ductus arteriosus

• Left atrial enlargement

• Main pulmonary artery mass (poststenotic dilatation)

• Hiatal hernia

• Diaphragmatic hernia or mass

• Aortic aneurysm

• Gastroesophageal intussusception

• Peritoneopericardial diaphragmatic hernia

Myocardial Diseases

Differential Diagnosis, Dogs

Dilated Cardiomyopathy

Primary (idiopathic, most common)

• Genetic (Doberman Pinscher, Boxer, Cocker Spaniel, Great Dane, Portuguese Water Dog, Newfoundland, Dalmatian, Irish Wolfhound)

Secondary

Nutritional Deficiencies

• l-Carnitine (Boxer, Doberman Pinscher, Great Dane, Irish Wolfhound, Newfoundland, Cocker Spaniel)

• Taurine

Myocardial Infection

• Viral myocarditis (acute viral infections, e.g., parvovirus)

• Bacterial myocarditis (secondary to bacteremia from infections elsewhere in body)

• Lyme disease: Borrelia burgdorferi

• Protozoal myocarditis (Trypanosoma cruzi [Chagas disease], Toxoplasma gondii, Neospora caninum, Babesia canis, Hepatozoon canis)

• Fungal myocarditis (rare, Aspergillus, Cryptococcus, Coccidioides, Histoplasma, Paecilomyces spp.)

• Rickettsial myocarditis (rare, Rickettsia rickettsii, Ehrlichia canis, Bartonella spp.)

• Algae-like organisms (rare, Prototheca spp.)

• Nematode larval migration (Toxocara spp.)

Trauma

 

Ischemia

 

Infiltrative Neoplasia

 

Hyperthermia

 

Irradiation

 

Electric Shock

 

Cardiotoxins

• Doxorubicin; ethyl alcohol; plant toxins such as foxglove, black locust, buttercup, lily of the valley, and gossypol; cocaine; anesthetic drugs; catecholamines; monensin

Hypertrophic Cardiomyopathy (uncommon in dogs)

 

Arrhythmogenic Right Ventricular Cardiomyopathy (rare)

 

Noninfective Myocarditis

• Catecholamines; heavy metals; antineoplastic drugs (doxorubicin, cyclophosphamide, 5-fluorouracil, interleukin-2, interferon-α); stimulant drugs (thyroid hormone, cocaine, amphetamines, lithium)

• Immune-mediated diseases, pheochromocytoma

• Wasp and scorpion stings, snake venom, spider bite

Differential Diagnosis, Cats

Hypertrophic Cardiomyopathy

Primary (Idiopathic)

• Maine Coon, Persian, Ragdoll, and American shorthair may be predisposed.

Secondary

• Hyperthyroidism

• Hypersomatotropism (acromegaly)

• Infiltrative myocardial disease (lymphoma)

Restrictive Cardiomyopathy

 

Dilated Cardiomyopathy

• Taurine-deficient diets

• Doxorubicin

• End stage of other myocardial metabolic, toxic, or infectious process

Arrhythmogenic Right Ventricular Cardiomyopathy

 

Myocarditis

• Viral (coronavirus, other viruses)

• Bacterial (bacteremia, Bartonella spp.)

• Protozoal (Toxoplasma gondii)

Murmurs

Clinical Findings

Systolic Murmurs

• Functional murmurs (point of maximal impulse [PMI] over left-sided heart base, decrescendo or crescendo-decrescendo)

  • •
    Innocent puppy murmurs
  • •
    Physiologic murmurs (anemia, fever, high sympathetic tone, hyperthyroidism, peripheral arteriovenous fistula, marked bradycardia, hypoproteinemia, athletic heart)

• Mitral valve insufficiency (left apex, typically holosystolic)

• Ejection murmurs (typically left-sided heart base)

  • •
    Subaortic stenosis (low left base and right base)
  • •
    Pulmonic stenosis (high left base)
  • •
    Dynamic muscular obstruction
• Right-sided murmurs (usually holosystolic)

  • •
    Tricuspid insufficiency (right apex, may see jugular pulse)
  • •
    Ventricular septal defect (PMI over right sternal border)

Diastolic Murmurs

• Aortic insufficiency from bacterial endocarditis (left-sided heart base)

• Aortic valve congenital malformations (left base)

• Aortic valve degenerative disease (left base)

• Pulmonic insufficiency (left base)

Continuous Murmurs

• Patent ductus arteriosus (PMI high left base above pulmonic area)

Concurrent Systolic and Diastolic Murmurs (To-and-Fro Murmurs)

• Subaortic stenosis with aortic insufficiency

• Pulmonic stenosis with pulmonic insufficiency

Grading

• Grade I: Very soft murmur; heard only in quiet surroundings after minutes of listening

• Grade II: Soft murmur but easily heard

• Grade III: Moderate-intensity murmur

• Grade IV: Loud murmur; no precordial thrill

• Grade V: Loud murmur with palpable precordial thrill

• Grade VI: Very loud murmur; can be heard with stethoscope off chest wall; palpable precordial thrill

Pericardial Effusion

Differential Diagnosis

Bacterial Pericarditis

• Secondary to foxtail (Hordeum spp.) migration

• Secondary to penetrating animal bite

• Disseminated tuberculosis

Fungal Pericarditis

• Coccidioidomycosis

• Aspergillosis

• Actinomycosis

Viral Pericarditis

• Feline infectious peritonitis (FIP)

• Canine distemper virus

Protozoal Pericarditis

• Toxoplasmosis

• Other systemic protozoal infections

Left Atrial Rupture (Secondary to Mitral Valve Disease)

 

Neoplasia

• Hemangiosarcoma

• Mesothelioma

• Heart base tumor (aortic body tumor or chemodectoma, ectopic thyroid tumor, ectopic parathyroid tumor, connective tissue neoplasms)

• Lymphosarcoma

• Rhabdomyosarcoma

Other

• Penetrating trauma

• Pericardioperitoneal diaphragmatic hernia

• Hypoalbuminemia

• Pericardial cyst

• Coagulation disorders

• Congestive heart failure

• Uremia

• Idiopathic

Pleural Effusion

Differential Diagnosis

Transudates and Modified Transudates

• Right-sided heart failure

• Pericardial disease

• Hypoalbuminemia

• Neoplasia

• Diaphragmatic hernia

Nonseptic Exudates

• Feline infectious peritonitis (FIP)

• Neoplasia

• Diaphragmatic hernia

• Lung lobe torsion

Septic Exudates

• Pyothorax

Chylous Effusion

• Chylothorax

Hemorrhage

• Trauma

• Bleeding disorder

• Neoplasia

• Lung lobe torsion

Diagnostic Approach in Dogs and Cats with Pleural Effusion Based on Fluid Type

Pure and Modified Transudates

• Right-sided heart failure, pericardial effusion (evaluate pulses, auscultation, ECG, thoracic radiography, echocardiography)

• Hypoalbuminemia (serum albumin concentration)

• Neoplasia, diaphragmatic hernia (thoracic radiography, thoracic ultrasound, CT, thoracoscopy, thoracotomy)

Nonseptic Exudates

• Feline infectious peritonitis (pleural fluid cytology [most reliable test], CBC, serum chemistry, ophthalmoscopic examination, serum or fluid electrophoresis, coronavirus antibody titer, PCR of tissues or effusion)

• Neoplasia, diaphragmatic hernia (thoracic radiography, thoracic ultrasound, CT, thoracoscopy, thoracotomy)

• Lung lobe torsion (thoracic radiography, ultrasound, bronchoscopy, thoracotomy)

Septic Exudates

• Pyothorax (Gram stain, aerobic and anaerobic culture, cytology)

Chylous Effusion

• Chylothorax (protein concentration, nucleated cell count, cytology, triglyceride)

Hemorrhagic

• Trauma (history)

• Bleeding disorder (systemic examination, coagulation tests platelet count)

• Neoplasia (thoracic radiography, thoracic ultrasound, CT, thoracoscopy, thoracotomy)

• Lung lobe torsion (thoracic radiography, ultrasound, bronchoscopy, thoracotomy)

Pulmonary Disease

Differential Diagnosis Based on Radiographic Patterns

Alveolar Pattern

• Pulmonary edema (cardiogenic or noncardiogenic)

• Infectious pneumonia (bacterial, parasitic, protozoal, viral)

• Aspiration pneumonia

• Atelectasis

• Drowning

• Smoke inhalation

• Hemorrhage

  • •
    Neoplasia (primary and metastatic)
  • •
    Fungal pneumonia (severe)
  • •
    Pulmonary contusion
  • •
    Thromboembolic disease
  • •
    Systemic coagulopathy

Bronchial Pattern

• Feline bronchitis/asthma

• Allergic bronchitis

• Bacterial bronchitis

• Canine chronic bronchitis

• Bronchiectasis

• Pulmonary parasites

• Bronchial calcification

Vascular Pattern

Enlarged Arteries

• Heartworm disease

• Thromboembolic disease

• Pulmonary hypertension

Enlarged Veins

• Left-sided heart failure

Enlarged Arteries and Veins (Pulmonary Overcirculation)

 

Left-to-Right Shunts

• Patent ductus arteriosus

• Ventricular septal defect

• Atrial septal defect

Small Arteries and Veins

Pulmonary Undercirculation

• Cardiovascular shock

• Hypovolemia

  • •
    Severe dehydration
  • •
    Blood loss
  • •
    Hypoadrenocorticism

• Pulmonic valve stenosis

Hyperinflation of Lungs

• Feline bronchitis

• Allergic bronchitis

Nodular Interstitial Pattern

• Mycotic infection

  • •
    Blastomycosis
  • •
    Histoplasmosis
  • •
    Coccidioidomycosis

• Neoplasia

• Pulmonary parasites

  • •
    Aelurostrongylus infection
  • •
    Paragonimus infection
• Pulmonary abscess

  • •
    Bacterial pneumonia
  • •
    Foreign body

• Pulmonary infiltrates with eosinophils

• Miscellaneous inflammatory diseases

• Inactive lesions

Reticular Interstitial Patterns

• Infection

  • •
    Viral pneumonia
  • •
    Bacterial pneumonia
  • •
    Toxoplasmosis
  • •
    Mycotic pneumonia

• Parasitic infestation

• Neoplasia

• Pulmonary fibrosis

• Pulmonary infiltrates with eosinophils

• Miscellaneous inflammatory diseases

• Hemorrhage (mild)

• Old dog lung

Pulmonary Edema

Causes

Vascular Overload

• Cardiogenic

  • •
    Left-sided heart murmur
  • •
    Left-to-right shunt

• Overhydration

Decreased Plasma Oncotic Pressure

• Hypoalbuminemia

  • •
    Gastrointestinal loss
  • •
    Renal loss (glomerular disease)
  • •
    Liver disease (lack of production)
  • •
    Iatrogenic overhydration

Increased Vascular Permeability

• Sepsis

• Shock

• Drugs or toxins

• Snake envenomation

• Cisplatin (cats)

• Trauma

  • •
    Pulmonary
  • •
    Multisystemic
• Inhaled toxins

  • •
    Smoke inhalation
  • •
    Gastric acid aspiration
  • •
    Oxygen toxicity

• Electrocution

• Pancreatitis

• Uremia

• Virulent babesiosis

• Disseminated intravascular coagulation

• Inflammation/Vasculitis

Other Causes

• Thromboembolism

• Postobstruction (strangulation, laryngeal paralysis, pulmonary reexpansion)

• Near-drowning

• Neurogenic edema

  • •
    Seizures
  • •
    Head trauma

• Lung lobe torsion

• Bacterial pneumonia

• Pulmonary contusion

• Hyperoxia

• High altitude

• Air embolus

• Pheochromocytoma

Lymphatic Obstruction (rare)

• Neoplasia

Pulmonary Thromboembolism

Causes

Embolization of Thrombi (any condition that predisposes to venous stasis, endothelial injury, and hypercoagulability)

• Heartworm disease

• Immune-mediated hemolytic anemia

• Systemic inflammatory disease

• Neoplasia

• Cardiac disease

• Cardiomyopathy

• Endocarditis

• Congestive heart failure

• Protein-losing nephropathy

• Protein-losing enteropathy

• Hyperadrenocorticism

• Pancreatitis

• Disseminated intravascular coagulation

• Anatomic abnormality (e.g., aneurysm, A-V fistula)

• Hyperviscosity (polycythemia, leukemia, hyperglobulinemia)

• Hypoviscosity (anemia)

• Sepsis

• Shock

• Intravenous catheterization

• Injection of irritating substance

• Prolonged recumbency

• Reperfusion injury

• Atherosclerosis/Arteriosclerosis

• Trauma

• Recent surgery

• Hyperhomocysteinemia

Embolization of Parasites

• Heartworm disease

Embolization of Fat

 

Embolization of Neoplastic Cells

 

Tachycardia, Sinus

Causes

• Anxiety/fear

• Excitement

• Exercise

• Pain

• Hyperthyroidism

• Hyperthermia/fever

• Anemia

• Hypoxia

• Shock

• Hypotension

• Sepsis

• Drugs (anticholinergics, sympathomimetics)

• Toxicity (e.g., chocolate, hexachlorophene)

• Electric shock

SECTION II. Dermatologic Disorders

• Allergic Skin Disease

• Alopecia, Endocrine

• Claw Disorders

• Erosions and Ulcerations of Skin or Mucous Membranes

• Folliculitis

• Otitis Externa, Chronic

• Parasitic Dermatoses

• Pigmentation

• Pyoderma

Allergic Skin Disease

Clinical Findings

Flea Allergy

Dogs

• Papular rash

• Caudal distribution of lesions most common

Cats

• Miliary dermatitis, especially over caudal back, around neck and chin

• Eosinophilic granuloma complex

Atopy and Cutaneous Signs of Food Hypersensitivity

• Signs of these two types of allergy are similar.

• Atopy tends to occur primarily in young adults, whereas food hypersensitivity can begin at any age. Atopy is usually seasonal at first but may become less seasonal.

Dogs

• Papular rash

• Pruritus and self-trauma

• Lesions of face, ears, feet, and perineum

• Recurrent otitis externa

• Excoriation

• Lichenification

• Pigmentary changes

• Secondary pyoderma

Cats

• Miliary dermatitis

• Eosinophilic dermatitis

Allergic Contact Dermatitis

• Rarest of allergic dermatoses

• Lesions tend to be confined to hairless or sparsely haired skin (ventral abdomen, neck, and chest; ventral paws but not pads; perineum; lateral aspect of pinnae).

• Acutely: Erythema, macules, papules, vesicles

• Chronically: Alopecic plaques, hyperpigmentation, hypopigmentation, excoriation, lichenification

Alopecia, Endocrine

Causes

• Hypothyroidism

• Hyperadrenocorticism

• Diabetes mellitus

• Adrenal sex hormone deficiency (Alopecia X)

• Growth hormone deficiency (pituitary dwarfism)

• Growth hormone-responsive dermatosis in adult dogs

• Castration-responsive dermatosis

• Hyperestrogenism

  • •
    Sertoli cell tumor (male dog)
  • •
    Intact female dog
• Hypoestrogenism (poorly understood)

  • •
    Estrogen-responsive dermatosis of spayed female dogs
  • •
    Feline endocrine alopecia
• Hypoandrogenism

  • •
    Testosterone-responsive dermatosis (male dog)
  • •
    Feline endocrine alopecia

• Telogen defluxion (effluvium): often after recent pregnancy or diestrus

• Progestin excess (excess of progesterone or 17-hydroxyprogesterone)

Clinical Findings

Nonspecific Features of Endocrine Disease

• Bilaterally symmetric alopecia

• Follicular dilation, follicular keratosis, follicular atrophy

• Orthokeratotic hyperkeratosis

• Predominance of telogen hair follicles

• Sebaceous gland atrophy

• Epidermal atrophy

• Thin dermis

• Epidermal melanosis

• Dermal collagen atrophy

Features Suggestive of Specific Endocrine Disorder

• Hypothyroidism

  • •
    Vacuolated and/or hypertrophied arrector pili muscles, increased dermal mucin content, thick dermis
• Hyperadrenocorticism

  • •
    Calcinosis cutis, comedones, absence of erector pili muscles
• Hyposomatotropism

  • •
    Decreased amount and size of dermal elastin fibers
• Growth hormone and castration-responsive dermatoses

  • •
    Excessive trichilemmal keratinization (flame follicles)

Claw Disorders

Differential Diagnosis for Abnormal Claws

Bacterial Claw Infection—almost always secondary to an underlying cause

• •Trauma—usually one claw affected
• •Hypothyroidism
• •Hyperadrenocorticism
• •Allergies
• •Autoimmune disorders
• •Symmetrical lupoid onychodystrophy
• •Neoplasia

Fungal Claw Infection

• •Typically caused by dermatophytes

Symmetrical Lupoid Onychodystrophy

• •Suspected to be immune mediated. German shepherds and Rottweilers may be predisposed. Acute onset of claw loss, initially 1–2 but eventually all claws slough. Replacement claws are misshapen, soft or brittle, discolored, and friable and usually slough again. Feet are painful and pruritic. Paronychia is uncommon unless secondary bacterial infection is present.

Drug Eruption

 

Vasculitis

 

Diagnostic Tests for Abnormal Claws

• •Cytology—suppurative to pyogranulomatous inflammation with bacteria
• •Bacterial culture of exudates from claw or claw fold. Mixed infections common. Staphylococcus spp. usually isolated
• •Fungal culture—Trichophyton spp. most commonly isolated but may also see Microsporum spp. or Malassezia spp.
• •Radiography—rule out osteomyelitis
• • Dermatohistopathology—(P3 amputation), only recommended to rule out neoplasia. With symmetric lupoid onychodystrophy, see basal cell hydropic degeneration, degeneration or apoptosis of individual keratinocytes in the basal layer, pigmentary incontinence, and lichenoid interface dermatitis. Systemic lupoid onychodystrophy is most commonly diagnosed by typical history and clinical signs along with ruling out other differentials.

Erosions and Ulcerations of Skin or Mucous Membranes

Differential Diagnosis, Dogs

Excoriation from Any Pruritic Skin Disease

 

Infection

Bacterial Pyoderma

• Surface (pyotraumatic moist dermatitis, intertrigo)

• Deep (folliculitis, furunculosis, bacterial stomatitis)

Fungal

• Yeast infection (Malassezia pachydermatis, Candida spp.)

• Dermatophytosis

• Systemic fungal infection (blastomycosis, coccidioidomycosis, cryptococcosis, histoplasmosis, others)

• Subcutaneous mycoses (pythiosis, zygomycosis, phaeohyphomycosis, sporotrichosis, eumycotic mycetoma, others)

Parasitic

• Demodicosis

Neoplasia

• Squamous cell carcinoma

• Epitheliotrophic lymphoma

Metabolic Derangements

• Uremia/renal failure

• Necrolytic migratory erythema

• Calcinosis cutis (hyperadrenocorticism)

Physical/Chemical Injury

• Drug reactions

• Urine scald

• Thermal injury (burn, freeze)

• Solar injury

Immune-Mediated Disorders

• Discoid lupus erythematosus (DLE)

• Pemphigus

• Uveodermatologic syndrome

• Miscellaneous autoimmune subepidermal vesiculobullous diseases (bullous pemphigoid, epidermolysis acquisita, linear IgA bullous disease, mucocutaneous pemphigoid, bullous systemic lupus type 1)

Miscellaneous

• Arthropod bites

• Dermatomyositis

• Dystrophic epidermolysis bullosa, junctional epidermolysis bullosa

• Idiopathic ulceration of Collies

• Toxic epidermal necrolysis, erythema multiforme

Differential Diagnosis, Cats

Infection

Viral

• Calicivirus

• Herpesvirus

Bacterial

• Atypical mycobacteriosis

Fungal

• Cryptococcosis

• Systemic and subcutaneous mycoses

• Sporotrichosis

Neoplasia

• Squamous cell carcinomas (especially white, outdoor cats)

• Fibrosarcoma

• Cutaneous lymphoma

Metabolic Derangements

• Uremia/renal disease

Physical/Chemical Injury

• Thermal

• Drug reactions

Immune-Mediated Disorders

• Bullous pemphigoid

• Pemphigus foliaceus

• Plasma cell pododermatitis

• Toxic epidermal necrolysis

Inflammatory/Allergic Disorders

• Eosinophilic plaque

• Indolent ulcer

• Arthropod bites

Miscellaneous/Idiopathic

• Dystrophic epidermolysis bullosa

• Idiopathic ulceration of dorsal neck

• Junctional epidermolysis bullosa

Folliculitis

Differential Diagnosis

Superficial Folliculitis

• Inflammation of hair follicles

  • •
    Bacterial pyoderma
  • •
    Fungal (dermatophytosis)
  • •
    Parasitic (demodicosis, Pelodera dermatitis)

Deep Folliculitis/Furunculosis

• Inflammation of hair follicles with subsequent follicular rupture into dermis and subcutaneous tissues

  • •
    Deep pyodermas

Otitis Externa, Chronic

Primary Causes

Allergy

• Atopy

• Adverse reactions to foods

• Contact dermatitis

Parasites

• Otodectes cynotis

• Notoedres cati

• Sarcoptes scabiei

• Demodex spp.

• Chiggers

• Flies

• Ticks (spinous ear tick)

Dermatophytes

 

Endocrine Disorders

• Hypothyroidism

Foreign Bodies

• Foxtails, hair, etc.

Glandular Conditions

• Ceruminous gland hyperplasia

• Sebaceous gland hyperplasia or hypoplasia

• Altered type or rate of secretions

Autoimmune Diseases

• Systemic lupus erythematosus (SLE)

• Pemphigus foliaceus/erythematosus

• Cold agglutinin disease

• Juvenile cellulitis

Viruses

• Distemper

Miscellaneous

• Solar dermatitis

• Frostbite

• Vasculitis/vasculopathy

• Eosinophilic dermatitis

• Sterile eosinophilic folliculitis

• Relapsing polychondritis

Predisposing Factors

Conformation

• Stenotic canals

• Hair in canals

• Pendulous pinnae

• Hairy, concave pinna

Excessive Moisture

• Swimmer's ear

• High-humidity climate

Excessive Cerumen Production

• Secondary to underlying disease

• Primary (idiopathic)

Treatment Effects

• Trauma from cotton swabs

• Topical irritants

• Superinfections from altering microflora

Obstructive Ear Disease

• Polyps

• Granulomas

• Tumors

Systemic Disease

• Immunosuppression

• Debilitation

• Negative catabolic states

Perpetuating Factors

Bacteria (most commonly Staphylococcus spp., Streptococcus spp., Pseudomonas spp., Proteus, Escherichia coli )

 

Yeast (Malassezia pachydermatis)

 

Progressive Pathologic Changes

• Hyperkeratosis

• Hyperplasia

• Epithelial folds

• Apocrine gland hypertrophy

• Hidradenitis

• Fibrosis

Otitis Media

• Purulent

• Caseated or keratinous

• Cholesteatoma

• Proliferative

• Destructive osteomyelitis

Parasitic Dermatoses

Classification

Fleas (Ctenocephalides felis most common)

• Flea infestation

• Flea allergy dermatitis

  • •
    Caudal distribution of lesions (dogs)
  • •
    Miliary dermatitis (cats)

Demodicosis

• Follicular infection (Demodex canis, Demodex felis)

• Epidermal infection (Demodex gatoi, short-tailed demodectic mite of dogs)

Sarcoptic Mange

• Sarcoptes scabiei (dogs, rarely cats)

• Notoedres cati (cats, rarely dogs)

Ear Mites

• Otodectes cynotis (common in both dogs and cats)

Cheyletiellosis

• Cheyletiella yasguri (primary host is dogs)

• C. blakei (primary host is cats)

• C. parasitovorax (primary host is rabbits)

• All Cheyletiella species freely contagious from one species to another

Chiggers

• Larval stage (six-legged bright red or orange) is the parasitic stage; nymph and adult are free living.

Ticks

• Brown dog tick (Rhipicephalus sanguineus)

• American dog tick (Dermacentor variabilis)

• Rocky Mountain wood tick (Dermacentor andersoni)

• Lone star tick (Amblyomma americanum)

• Deer tick (Ixodes dammini): primary vector of Borrelia burgdorferi

• Spinous ear tick (Otobius megnini)

Lice

• Sucking lice of dogs (Linognathus setosus)

• Biting lice of dogs (Trichodectes canis, Heterodoxus springer)

• Lice of cats (Felicola subrostrata)

Insects of Order Diptera

• Mosquitoes: eosinophilic dermatitis (especially cats)

• Black flies, stable flies, horn flies, houseflies: attack ear pinnae of dogs

• Myiasis (development of fly larvae in skin or haircoat): screwworm, blow flies, flesh flies

• Cuterebra fly larva

Helminth Parasites

• Hookworm dermatitis (Ancylostoma, Uncinaria)

• Pelodera dermatitis (Peloderma strongyloides)

• Dracunculiasis (Dracunculus insignis)

Pigmentation

Differential Diagnosis for Changes in Skin Pigmentation

Hypopigmentation

• Vitiligo (Tervuren, Rottweiler, Doberman Pinscher, Newfoundland, Collie, German Shorthaired Pointer, Old English Sheepdog, Siamese cat)

• Uveodermatologic syndrome (northern breeds such as Siberian Husky, Samoyed, Akita)

• Acquired idiopathic hypopigmentation of nose (Labrador Retriever, Golden Retriever, Malamute, Siberian Husky, Samoyed, Poodle, German Shepherd)

• Discoid lupus (German Shepherd, Collie, others)

• Dermatomyositis (Collie, Shetland Sheepdog, Beauceron Shepherd)

Hyperpigmentation

Postinflammatory Hyperpigmentation

Any Chronic Pruritic Skin Disease

• Atopy

• Adverse food reactions

• Pyoderma

• Malassezia dermatitis

• Sarcoptic mange

• Erythema multiforme

• Many others

Demodicosis

 

Endocrinopathies

• Hypothyroidism

• Hyperadrenocortism

Dermatophytosis

 

Nevus

 

Lentigo

 

Neoplasia (melanoma)

 

Pyoderma

Differential Diagnosis

Surface Pyoderma

• Pyotraumatic dermatitis (acute moist dermatitis, “hot spot”)

• Intertrigo (skin fold dermatitis)

Superficial Pyoderma

• Impetigo (subcorneal pustules of sparsely haired skin)

  • •
    Puppy pyoderma
• Bullous impetigo

  • •
    Hyperadrenocorticism, hypothyroidism, diabetes mellitus
• Mucocutaneous pyoderma

  • •
    Dogs (German Shepherds predisposed)
• Superficial bacterial folliculitis

  • •
    Staphylococcus pseudintermedius most common
  • •
    Local trauma secondary to pruritus (allergy, fleas, scabies, demodicosis, etc.)

• Dermatophilosis (rare, actinomycotic superficial crusting dermatitis) methicillin-resistant Staphylococcus pseudintermedius

Deep Pyoderma

• Always secondary to predisposing problem

• Localized lesion (laceration, penetrating wound, animal bite, foreign body)

• Generalized (suspect underlying systemic disease)

• Clinical syndromes associated with deep pyoderma

  • •
    Deep folliculitis, furunculosis, cellulitis
  • •
    Pyotraumatic folliculitis
  • •
    Muzzle folliculitis and furunculosis
  • •
    Pododermatitis (interdigital pyoderma)
  • •
    German Shepherd dog folliculitis, furunculosis, cellulitis
  • •
    Acral lick furunculosis
  • •
    Anaerobic cellulites
  • •
    Subcutaneous abscesses
  • •
    Bacterial pseudomycetoma
  • •
    Mycobacterial granulomas

    • •
      Cutaneous tuberculosis (Mycobacterium tuberculosis, M. bovis)
    • •
      Feline leprosy (M. lepraemurium)
    • •
      Opportunistic mycobacterial granulomas
  • •
    Actinomycosis
  • •
    Actinobacillosis
  • •
    Nocardiosis

Miscellaneous Bacterial Infections

• Brucellosis, plague, borreliosis, trichomycosis axillaris, l-form infections

SECTION III. Endocrinologic and Metabolic Disorders

• Acromegaly

• Adrenal Tumors

• Cretinism (Hypothyroidism in Puppies)

• Diabetes Insipidus

• Diabetic Ketoacidosis

• Diabetes Mellitus

• Gastrinoma (Zollinger-Ellison Syndrome)

• Glucagonoma

• Hyperadrenocorticism

• Hyperglycemia

• Hypoadrenocorticism

• Hypoglycemia

• Hyponatremia/Hyperkalemia

• Insulinoma

• Parathyroidism

• Pheochromocytoma

• Pituitary Dwarfism

• Thyroid Disease

Acromegaly

• In dogs, acromegaly is caused by endogenous progesterone from the luteal phase of the estrous cycle or by exogenous progesterone used for estrous prevention. Elevated progesterone, in turn, stimulates excessive growth hormone secretion of mammary origin. In cats, acromegaly is caused by a pituitary adenoma, usually a macroadenoma, which secretes excessive amounts of growth hormone. Physical changes are less pronounced in cats than in dogs.

Clinical Findings, Dogs

• Hypertrophy of mouth, tongue, and pharynx

• Thick skin folds, myxedema, hypertrichosis

• Prognathism

• Wide interdental spacing

• Visceral organomegaly

• Insulin-resistant diabetes mellitus

• Polyuria

• Polyphagia

• Elevated alkaline phosphatase

Clinical Findings, Cats

• Physical changes most pronounced on head, but all the physical changes listed for dogs may be seen.

• Insulin-resistant diabetes mellitus (severe)

• Degenerative arthropathy/lameness

• Polyuria/polydipsia

• Polyphagia

• Panting

• Lethargy/exercise intolerance

• Dyspnea secondary to hypertrophic cardiomyopathy and heart failure

• Neurologic signs when macroadenoma becomes large

  • •
    Lethargy, stupor
  • •
    Adipsia
  • •
    Anorexia
  • •
    Temperature deregulation
  • •
    Circling
  • •
    Seizures
  • •
    Pituitary dysfunction

    • •
      Hypogonadism
    • •
      Hypothyroidism
    • •
      Hypoadrenocorticism (feline acromegaly may also coexist with pituitary-dependent hyperadrenocorticism)

Adrenal Tumors

Differential Diagnosis

Nonfunctional Adrenal Tumor (dog, rarely cat)

• No hormone secreted

• Diagnosis by exclusion

• Histopathology

Functional Adrenocortical Tumor

Cortisol-Secreting Tumor

• Hyperadrenocorticism (Cushing syndrome) (dog, rarely cat)

• Diagnosis by adrenocorticotropic hormone (ACTH) stimulation test, low-dose dexamethasone suppression test, adrenal ultrasound, CT scan

Aldosterone-Secreting Tumor

• Hyperaldosteronism (Conn syndrome) (cat, rarely dog)

• Diagnosis by assessing Na/K, ACTH stimulation test (measure aldosterone)

Progesterone-Secreting Tumor

• Mimics hyperadrenocorticism (cat, less commonly dog)

• Diagnosis by measuring serum progesterone

Steroid Hormone Precursor–Secreting Tumor

• 17-hydroxyprogesterone

• Mimics hyperadrenocorticism (dog)

• Diagnosis by ACTH stimulation test (measure steroid hormone precursors)

• Deoxycorticosterone

• Mimics hyperadrenocorticism (dog)

• Diagnosis by ACTH stimulation test (measure steroid hormone precursors)

Functional Adrenomedullary Tumor

Epinephrine-Secreting Tumor

• Pheochromocytosis (dog, rarely cat)

• Diagnosis by exclusion, histopathology

Cretinism (Hypothyroidism in Puppies)

Clinical Findings

• Dwarfism

• Short, broad skull with short thick neck

• Enlarged cranium

• Shortened limbs

• Shortened mandible

• Mental dullness

• Alopecia

• Retention of puppy coat

• Kyphosis

• Inappetence

• Hypothermia

• Constipation

• Gait abnormalities

• Delayed dental eruption

• Macroglossia

• Dry coat

• Thick skin

• Lethargy

• Dyspnea

• Goiter

Diabetes Insipidus

Differential Diagnosis

• Features of diabetes insipidus include polyuria, polydipsia, and a near-continuous demand for water. Only the following three disorders can cause the degree of polyuria and dilute urine seen with diabetes insipidus:

  • •
    Central diabetes insipidus
  • •
    Nephrogenic diabetes insipidus
  • •
    Primary polydipsia

Causes in Dogs and Cats

Central Diabetes Insipidus

• Idiopathic

• Traumatic

• Neoplasia

  • •
    Primary pituitary neoplasm
  • •
    Meningioma
  • •
    Craniopharyngioma
  • •
    Chromophobe adenoma
  • •
    Chromophobe adenocarcinoma
  • •
    Metastatic neoplasia

• Pituitary malformation

• Cysts

• Inflammation

• Parasitic lesions

• Complication of pituitary surgery

• Familial?

Nephrogenic Diabetes Insipidus

• Polyuria caused by nonresponsiveness to antidiuretic hormone (ADH).

• Primary idiopathic

• Primary familial (Husky)

• Secondary acquired

  • •
    Renal insufficiency or failure
  • •
    Hyperadrenocorticism
  • •
    Hypoadrenocorticism
  • •
    Hepatic insufficiency
  • •
    Pyometra
  • •
    Hypercalcemia
  • •
    Hypokalemia
  • •
    Postobstructive diuresis
  • •
    Diabetes mellitus
  • •
    Normoglycemic glucosuria
  • •
    Hyperthyroidism
  • •
    Iatrogenic or drug induced
  • •
    Renal medullary solute washout

Diabetic Ketoacidosis

Clinical Findings

• No signs may be seen early with diabetic ketoacidosis.

Historical Findings

• Lethargy

• Anorexia

• Vomiting

Physical Examination Findings

• Dehydration

• Depression

• Weakness

• Tachypnea

• Vomiting

• Acetone odor on breath

• Slow, deep breaths (secondary to metabolic acidosis)

• Abdominal pain/abdominal distension secondary to concurrent pancreatitis

Clinicopathologic Findings

• Hyperglycemia

• Metabolic acidosis

• Hypercholesterolemia/lipemia

• Increased alkaline phosphatase (ALP)

• Increased alanine aminotransferase (ALT)

• Increased blood urea nitrogen (BUN)/creatinine

• Hyponatremia

• Hypochloremia

• Hypokalemia

• Increased amylase/lipase

• Hyperosmolality

• Glycosuria

• Ketonuria

• Urinary tract infection

Diabetes Mellitus

Potential Factors in Etiopathogenesis

• Obesity

• Pancreatitis

• Immune-mediated insulitis

• Concurrent hormonal disease

  • •
    Hyperadrenocorticism
  • •
    Diestrus-induced excess of growth hormone
  • •
    Hypothyroidism

• Genetics (dog, possibly cat)

• Drugs

  • •
    Glucocorticoids
  • •
    Megestrol acetate (cat)

• Infection

• Concurrent illness

  • •
    Renal insufficiency
  • •
    Cardiac disease

• Hyperlipidemia (dog, possibly cat)

• Islet amyloidosis

Clinicopathologic Abnormalities, Uncomplicated Diabetes Mellitus

Complete Blood Count

• Often normal

• Leukocytosis if pancreatitis or infection present

Serum Chemistry

• Hyperglycemia

• Mild increase in alkaline phosphatase (ALP) and alanine aminotransferase (ALT)

• Hypercholesterolemia/hypertriglyceridemia

Urinalysis

• Urine specific gravity normal to mildly decreased (>1.025)

• Glycosuria

• Variable ketonuria

• Bacteriuria

• Proteinuria

Ancillary Tests

• Increased amylase/lipase if pancreatitis present

• Normal serum trypsin-like immunoreactivity (TLI)

• Low TLI with exocrine pancreatic insufficiency

• High TLI with acute pancreatitis

• Normal to high TLI with chronic pancreatitis

• Low to normal serum insulin with insulin-dependent diabetes mellitus

• Low, normal, or increased serum insulin with non–insulin-dependent diabetes mellitus

Potential Complications

Common

• Iatrogenic hypoglycemia

• Polyuria/polydipsia

• Weight loss

• Cataracts (dog)

• Anterior uveitis

• Bacterial infections (especially urinary tract infection)

• Ketoacidosis

• Pancreatitis

• Peripheral neuropathy (cat)

• Hepatic lipidosis

Uncommon

• Peripheral neuropathy (dog)

• Glomerulopathy

• Glomerulosclerosis

• Retinopathy

• Exocrine pancreatic insufficiency

• Gastric paresis

• Diabetic diarrhea

• Diabetic dermatopathy

Causes of Insulin Resistance or Ineffectiveness in Dogs and Cats

Caused by Insulin Therapy

• Improper administration

• Inadequate dose

• Inactive insulin

• Diluted insulin

• Somogyi effect

• Inappropriate insulin administration

• Impaired insulin absorption

• Antiinsulin antibody excess

Caused by Concurrent Disorder

• Obesity

• Diabetogenic drugs

• Hyperadrenocorticism

• Hypothyroidism (dog)

• Hyperthyroidism (cat)

• Urinary tract infection

• Oral infections

• Chronic inflammation/pancreatitis

• Diestrus (bitch)

• Acromegaly (cat)

• Renal insufficiency

• Hepatic insufficiency

• Cardiac insufficiency

• Glucagonoma

• Pheochromocytoma

• Exocrine pancreatic insufficiency

• Hyperlipidemia

• Neoplasia

Clinical Findings Associated with Insulin-Secreting Tumors

• Seizures

• Weakness

• Collapse

• Ataxia

• Polyphagia

• Weight gain

• Muscle fasciculations

• Posterior weakness (neuropathy)

• Lethargy

• Nervousness

• Unusual behavior

Gastrinoma (Zollinger-Ellison Syndrome)

Clinical Findings

Clinical Signs

• Vomiting

• Weight loss

• Anorexia

• Diarrhea

• Gastric and duodenal ulceration

• Hematochezia

• Hematemesis

• Melena

• Obstipation

• Lethargy/depression

• Abdominal pain

• Esophageal pain and ulceration

• Regurgitation

• Fever

• Polydipsia

• Thin body condition

• Pallor

Clinicopathologic Findings

• Regenerative anemia

• Hypoproteinemia

• Neutrophilic leukocytosis

• Hypoalbuminemia

• Hypocalcemia

• Mild increases in hepatic enzymes

• Hypochloremia

• Hypokalemia

• Hyponatremia

• Metabolic acidosis

• Metabolic acidosis (secondary to vomiting)

• Hyperglycemia, hypoglycemia (uncommon)

Glucagonoma

Clinical Findings in Dogs

Clinical Signs

• Necrolytic migratory erythema (crusting skin rash of elbows, hocks, nose, scrotum, flank, ventral abdomen, distal extremities, and mucocutaneous junctions of mouth, eyes, prepuce and vulva)

• Footpad lesions

• Glucose intolerance/diabetes mellitus (caused by excess glycogenolysis and gluconeogenesis)

• Oral ulcerations

• Lethargy

• Weight loss

• Decreased appetite

• Muscle atrophy

• Peripheral lymphadenopathy

Clinicopathologic Findings

• Hyperglycemia

• Nonregenerative anemia

• Increased hepatic enzymes

• Decreased albumin

• Decreased globulin

• Decreased blood urea nitrogen (BUN)

• Decreased cholesterol

• Glucosuria

• Abdominal ultrasound lesions

  • •
    Increased echogenicity of portal and hepatic vein walls
  • •
    Diffuse hyperechogenicity
  • •
    Multiple small hypoechoic foci

Hyperadrenocorticism

Clinical Findings

Potential Clinical Signs

• Polyuria/polydipsia

• Alopecia

• Pendulous abdomen

• Hepatomegaly

• Polyphagia

• Muscle weakness

• Muscle atrophy

• Pyoderma

• Comedones

• Panting

• Pacing/restlessness

• Hyperpigmentation

• Systemic hypertension

• Testicular atrophy

• Anestrus

• Calcinosis cutis

• Facial nerve paralysis

• Pulmonary thromboembolism

Potential Clinicopathologic Findings

• Urinary tract infection/pyelonephritis

• Decreased urine specific gravity

• Increased serum alkaline phosphatase (ALP)

• Increased alanine aminotransferase (ALT)

• Hypercholesterolemia

• Hypertriglyceridemia

• Hyperglycemia (mild to moderate)

• Diabetes mellitus (uncommon)

• Increased serum bile acids

• Decreased BUN and creatinine (secondary to diuresis)

• Hypophosphatemia

• Stress leukogram

  • •
    Neutrophilia
  • •
    Lymphopenia
  • •
    Eosinopenia
  • •
    Monocytosis

• Thrombocytosis

• Mild erythrocytosis

• Decreased total serum thyroxine (T₄) or free T₄

• Urolithiasis

Hyperglycemia

Differential Diagnosis

• Diabetes mellitus

• Stress (physiologic in cat)

• Hyperadrenocorticism

• Drug therapy

  • •
    Glucocorticoids
  • •
    Progestagens
  • •
    Megestrol acetate
  • •
    Thiazide diuretics

• Dextrose-containing fluids

• Parenteral nutrition

• Postprandial effect (diets containing monosaccharides, disaccharides, propylene glycol)

• Exocrine pancreatic neoplasia

• Pancreatitis

• Renal insufficiency

• Acromegaly (cat)

• Pheochromocytoma (dog)

• Diestrus (bitch)

• Head trauma

Hypoadrenocorticism

Potential Clinical Findings

Clinical Signs

• Lethargy/depression

• Episodic weakness

• Vomiting

• Anorexia

• Waxing and waning illness

• Weight loss/failure to gain weight

• Bradycardia

• Dehydration/hypovolemia

• Diarrhea

• Polyuria or polydipsia

• Collapse

• Syncope

• Restlessness/shaking/shivering

• Regurgitation

• Muscle cramping

• Gastrointestinal hemorrhage/melena

• Abdominal pain

Potential Clinicopathologic Findings

• Hyponatremia

• Hyperkalemia

• Hypochloremia

• Decreased sodium/potassium ratio (<24:1)

• Azotemia

  • •
    Increased blood urea nitrogen (BUN)
  • •
    Increased creatinine
  • •
    Increased phosphate

• Decreased bicarbonate and total CO₂ concentrations

• Hypercalcemia

• Hypoglycemia

• Hypoalbuminemia

• Increased hepatic enzymes

• Metabolic acidosis

• Lymphocytosis

• Eosinophilia

• Relative neutropenia

• Anemia (usually nonregenerative)

• Variable urine specific gravity (<1.030)

Hypoglycemia

Differential Diagnosis

Excess Secretion of Insulin or Insulin-Like Factors

• Insulinoma

• Extrapancreatic tumor

• Islet cell hyperplasia

Decreased Glucose Production

• Toy breeds

• Neonates

• Malnutrition

• Pregnancy

• Fasting

• Hypoadrenocorticism

• Hypopituitarism

• Growth hormone deficiency

• Liver disease (portal caval shunt, chronic fibrosis/cirrhosis)

• Glycogen storage diseases

Excess Glucose Consumption

• Sepsis

• Extreme exercise

Drug-Associated Causes

• Insulin

• Oral hypoglycemics

• Many other drugs reported to cause hypoglycemia in humans

Spurious

• Blood cells not promptly separated from serum

Hyponatremia/Hyperkalemia

Differential Diagnosis

Hypoadrenocorticism

 

Renal or Urinary Tract Disease

• Urethral obstruction

• Acute renal failure

• Chronic oliguric or anuric renal failure

• Postobstructive diuresis

• Nephrotic syndrome

Severe Gastrointestinal Disease

• Parasitic infestation

  • •
    Whipworm (trichuriasis)
  • •
    Roundworm (ascariasis)
  • •
    Hookworm (ancylostomiasis)

• Salmonellosis

• Viral enteritis

  • •
    Parvovirus
  • •
    Canine distemper virus

• Gastric dilatation/volvulus

• Gastrointestinal perforation

• Severe malabsorption

• Hemorrhagic gastroenteritis

• Pancreatic disease

Severe Hepatic Failure

• Cirrhosis

• Neoplasia

Severe Metabolic or Respiratory Acidosis

 

Congestive Heart Failure

 

Massive Release of Potassium into Extracellular Fluid

• Crush injury

• Aortic thrombosis

• Rhabdomyolysis

  • •
    Heat stroke
  • •
    Exertional

• Massive sepsis

• Massive hemolysis

Pleural Effusion

 

Pregnancy

 

Lymphangiosarcoma

 

Pseudohyperkalemia

• Akitas and related breeds

• Severe leukocytosis (>100,000/mm³)

• Severe thrombocytosis (>1 million/mm³)

Diabetes Mellitus

 

Primary Polydipsia

 

Inappropriate Antidiuretic Hormone (ADH) Secretion

 

Drug Induced

• Potassium-sparing diuretics

• Nonsteroidal antiinflammatory drugs (NSAIDs)

• Angiotensin-converting enzyme (ACE) inhibitors

• Potassium-containing fluids

Insulinoma

Differential Diagnosis for Insulin-Secreting Beta-Cell Neoplasia

Excess Insulin or Insulin-Like Factors

• Insulinoma

• Extrapancreatic tumor

• Islet cell hyperplasia

Decreased Glucose Production

• Hypoadrenocorticism

• Hypopituitarism

• Growth hormone deficiency

• Liver disease

• Glycogen storage diseases

• Neonates

• Toy breeds

• Fasting

• Malnutrition

• Pregnancy

Excess Glucose Consumption

• Sepsis

• Extreme exercise

Drug-Associated Causes

• Insulin

• Oral hypoglycemics (sulfonylurea)

• Salicylates (e.g., aspirin)

• Acetaminophen

• β-blockers

• β₂-agonists

• Ethanol

• Monoamine oxidase inhibitors

• Tricyclic antidepressants

• Angiotensin-converting enzyme (ACE) inhibitors

• Antibiotics (e.g., tetracycline)

• Lidocaine overdose

• Lithium

Factitious Hypoglycemia

• Failure to separate blood cells from serum promptly

• Severe polycythemia or leukocytosis when serum separation delayed

Parathyroidism

Hyperparathyroidism, Primary—Clinical Findings

Clinical Signs

• Polyuria/polydipsia

• Weight loss

• Anorexia

• Lethargy, listlessness

• Urinary tract infection (UTI)

• Urolithiasis

• Vomiting

• Constipation

• Mental dullness, obtundation, coma

• Weakness, muscle wasting, shivering

Clinicopathologic Findings

• Hypercalcemia

• Increased ionized calcemia

• Low normal to low serum phosphorus

• Decreased urine specific gravity

• Hematuria

• Pyuria

• Crystalluria

• Bacteriuria

Hypoparathyroidism—Clinical Findings

Clinical Signs

• Seizures

• Facial rubbing, biting at feet

• Splinted abdomen

• Stiff gait

• Intermittent lameness

• Muscle fasciculations, cramping, tremors

• Fever

• Paroxysmal tachyarrhythmias

• Muffled heart sounds

• Weak pulses

• Disorientation

Clinicopathologic Findings

• Hypocalcemia

• Hyperphosphatemia

• Decreased serum parathyroid hormone concentration

Electrocardiographic Findings

• Deep, wide T waves

• Prolonged QT interval

• Bradycardia

Pheochromocytoma

Clinical Findings

• Intermittent weakness

• Intermittent collapse

• Panting

• Tachypnea

• Seizures

• Tachycardia

• Lethargy

• Inappetence

• Cardiac arrhythmias

• Restlessness

• Exercise intolerance

• Weak pulses

• Vomiting

• Diarrhea

• Weight loss

• Muscle wasting

• Polyuria/polydipsia

• Abdominal distension

• Rear limb edema

• Pale mucous membranes

• Abdominal pain

• Hemorrhage (epistaxis, surgical incision sites)

• Palpable abdominal mass

Pituitary Dwarfism

Clinical Findings

Musculoskeletal Signs

• Stunted growth

• Delayed growth plate closure

• Thin skeleton

• Immature facial features

• Square, chunky contour as adult

• Bone deformities

• Delayed dental eruption

Dermatologic Signs

• Soft, woolly haircoat

• Lack of guard hairs

• Alopecia; bilaterally symmetric trunk, neck, and proximal extremities

• Hyperpigmentation

• Thin, fragile skin

• Wrinkles

• Scales

• Comedones

• Papules

• Pyoderma

• Seborrhea sicca

• Retention of secondary hairs

Reproductive Signs

• Testicular atrophy

• Unilateral or bilateral cryptorchidism

• Flaccid penile sheath

• Failure to have estrous cycles

Other Signs

• Mental dullness

• Shrill, puppy-like bark

• Signs of secondary hypothyroidism

• Signs of secondary adrenal insufficiency

Thyroid Disease

Hyperthyroidism, Feline—Clinical Findings

Clinical Signs

• Weight loss/thin body condition

• Polyphagia

• Hyperactivity

• Palpable thyroid nodule (goiter)

• Tachycardia

• Vomiting

• Cardiac murmur

• Premature beats

• Gallop rhythm

• Aggressiveness

• Panting

• Pacing

• Restlessness

• Increased nail growth

• Alopecia

• Polyuria/polydipsia

• Diarrhea

• Increased fecal volume

• Muscle weakness

• Congestive heart failure (CHF)

• Dyspnea

• Ventroflexion of neck

• Unkempt coat/alopecia

• Tremor

• Weakness

• Anorexia

Hypothyroidism, Canine—Clinical Findings

Clinical Signs

• Lethargy/exercise intolerance

• Weight gain

• Cold intolerance

• Mental dullness

• Dermatologic signs

  • •
    Alopecia
  • •
    Superficial pyoderma
  • •
    Seborrhea sicca or oleosa
  • •
    Dry, scaly skin
  • •
    Changes in haircoat quality and color
  • •
    Hyperkeratosis
  • •
    Hyperpigmentation
  • •
    Comedones
  • •
    Hypertrichosis
  • •
    Ceruminous otitis
  • •
    Myxedema (cutaneous mucinosis)
  • •
    Poor wound healing
  • •
    Slow regrowth of hair
• Reproductive abnormalities

  • •
    Male: decreased libido, testicular atrophy, hypospermia
  • •
    Female: delayed estrus, silent estrus, failure to cycle, abortion, small litters, uterine inertia, weak or stillborn puppies
• Peripheral neuropathies

  • •
    Generalized peripheral neuropathies
  • •
    Specific peripheral neuropathies (especially cranial nerves, facial, trigeminal, vestibulocochlear)

• Cerebral dysfunction (myxedema coma [rare])

• Cardiovascular signs

  • •
    Sinus bradycardia, weak apex beat, low QRS voltages, inverted T waves, hypercholesterolemia leading to atherosclerosis (rare)

• Ocular abnormalities (corneal lipidosis, corneal ulceration, uveitis, secondary glaucoma, lipemia retinalis, retinal detachment, and keratoconjunctivitis sicca reported, but causal relationship not proven)

Clinicopathologic Changes

• Nonregenerative anemia

• Hypercholesterolemia

• Hypertriglyceridemia

• Mild increases in hepatic enzymes

SECTION IV. Gastroenterologic Disorders

• Chronic Constipation, Feline

• Diarrhea

• Dental and Oral Cavity Diseases

• Diseases of the Tongue

• Salivary Gland Disease

• Esophageal Disease

• Stomach Disorders

• Small Intestinal Disease

• Large Intestinal Disease

• Ileus

• Malabsorptive Disease

• Perianal Disease

• Protein-Losing Enteropathy

• Fecal Incontinence

Chronic Constipation, Feline

Differential Diagnosis

Neuromuscular Dysfunction

• •Colonic smooth muscle: idiopathic megacolon, aging
• •Spinal cord disease: lumbosacral disease, cauda equina syndrome, sacral spinal cord deformities (Manx cat)
• •Hypogastric or pelvic nerve disorders: traumatic injury, malignancy, dysautonomia

Mechanical Obstruction

• •Intraluminal: foreign material, neoplasia, rectal diverticula, perineal hernia, anorectal strictures
• •Intramural: neoplasia
• •Extraluminal: pelvic fractures, neoplasia

Inflammation

• •Perianal fistula, proctitis, anal sac abscess, anorectal foreign bodies, perianal bite wounds

Metabolic and Endocrine

• •Metabolic: dehydration, hypokalemia, hypercalcemia
• •Endocrine: hypothyroidism, obesity, nutritional secondary hyperparathyroidism

Environmental and Behavioral

• •Soiled litter box, inactivity, hospitalization, change in environment

Diarrhea

Causes of Diarrhea

Gastrointestinal Disease

• •Diffuse gastrointestinal disease (e.g., inflammation or lymphoma)
• •Gastric disease (achlorhydria, dumping syndromes)
• •Intestinal disease (primary small intestinal disease, primary large intestinal disease, dietary-induced such as food poisoning, gluttony, or sudden change of diet)

Nongastrointestinal Disease

• •Pancreatic disease (exocrine pancreatic insufficiency, pancreatitis, pancreatic carcinoma, gastrinoma or Zollinger-Ellison syndrome)
• •Liver disease (hepatocellular failure, intrahepatic and extrahepatic cholestasis)
• •Endocrine disease (classical hypoadrenocorticism, atypical hypoadrenocorticism, hyperthyroidism, hypothyroidism)
• •Renal disease (uremia, nephrotic syndrome)
• •Polysystemic infection (e.g., distemper, leptospirosis, infectious canine hepatitis in dogs, FIP, FeLV, FIV in cats)
• •Miscellaneous (toxemias such as pyometra and peritonitis, congestive heart failure, autoimmune disease, metastatic neoplasia, various toxins and drugs)

Classification of Diarrhea

Mechanistic

• •Secretory
• •Osmotic
• •Permeability (exudative)
• •Dysmotility
• •Mixed

Temporal

• •Acute
• •Chronic

Anatomic

• •Extraintestinal
• •Small intestinal
• •Large intestinal
• •Diffuse

Pathophysiologic

• •Biochemical
• •Allergic
• •Inflammatory
• •Neoplastic

Etiologic

• •Bacteria
• •Dietary
• •Fungal
• •Idiopathic
• •Parasitic
• •Viral

Causal

• •Exocrine pancreatic insufficiency, salmonellosis, lymphoma, other

Clinical

• •Acute, nonfatal, mild, self-limiting
• •Acute, severe potentially fatal
• •Acute systemic disease
• •Chronic
• •Chronic protein-losing

Dental and Oral Cavity Diseases

Differential Diagnosis

Trauma

• Fractures

  • •
    Crown
  • •
    Root
  • •
    Mandible
  • •
    Maxillary

• Avulsion

• Pulp injury

• Temporomandibular luxation

Caries

 

Feline Dental Resorptive Lesions

 

Periodontal Disease

• Gingivitis

• Gingival recession

• Bone loss, osteomyelitis

• Tooth loss

Tooth Root Abscess

 

Oronasal Fistula

 

Stomatitis (Faucitis, Glossitis, Pharyngitis)

• Feline immunodeficiency virus, feline leukemia virus, feline syncytium-forming virus

• Feline calicivirus, feline herpesvirus, feline infectious peritonitis

• Candidiasis

• Uremia

• Trauma (foreign objects, caustic agents, electric cord bite)

• Autoimmune disease (pemphigus, lupus, idiopathic vasculitis, toxic epidermal necrolysis)

• Feline idiopathic gingivitis/pharyngitis

Neoplasia

Malignant

• Fibrosarcoma

• Squamous cell carcinoma

• Melanoma

• Salivary gland neoplasms

Benign

• Epulis

  • •
    Fibromatous
  • •
    Acanthomatous
  • •
    Ossifying
  • •
    Papilloma
  • •
    Fibroma
  • •
    Lipoma
  • •
    Chondroma
  • •
    Osteoma
  • •
    Hemangioma
  • •
    Hemangiopericytoma
  • •
    Histiocytoma

Eosinophilic Granuloma Complex

• Linear granuloma

• Eosinophilic ulcer (usually on maxillary lips)

Sialocele

 

Diseases of the Tongue

Differential Diagnosis

Trauma

• •Mechanical injury (sharp objects)
• •Chemical injury
• •Electric shock (electric cord)
• • Foreign body (plant material, porcupine quill, linear foreign bodies)
• •Sublingual hyperplastic tissue (gum chewer's disease)

Viral

• •Calicivirus
• •Herpes virus
• •Papillomavirus

Neoplasia

• •Malignant melanoma
• •Squamous cell carcinoma
• •Benign tumors (lipoma, plasma cell tumor, granular cell tumors, fibroma)

Metabolic Disease (Uremia)

 

Sublingual Mucocele (Ranula)

 

Immune Mediated

• •Mucous membrane pemphigoid
• •Pemphigus vulgaris
• •Bullous pemphigoid
• •Systemic lupus erythematosus
• •Autoimmune vasculopathies (idiopathic, infectious, food allergies, drug reaction, neoplasia)

Eosinophilic granulomas

 

Contact Mucosal Ulceration from Calculus Contact

 

Calcinosis Circumscripta

 

Salivary Gland Disease

Differential Diagnosis

Salivary Neoplasia (more common in cats than dogs)

• Adenocarcinoma

• Squamous cell carcinoma

• Undifferentiated sarcoma

• Mucoepidermoid tumor

• Malignant mixed tumor

• Sarcoma

• Acinic cell carcinoma

• Adenoid cystic carcinoma

Salivary Mucocele

• Sublingual gland most commonly

Sialoadenitis

 

Sialadenosis

 

Esophageal Disease

Differential Diagnosis

Congenital

Obstruction

• Persistent right aortic arch

• Persistent right or left subclavian artery

• Other vascular ring anomaly

Idiopathic

 

Acquired

Obstruction

• Foreign body

• Cicatrix/stricture

• Neoplasia

  • •
    Carcinoma
  • •
    Spirocerca lupi–induced sarcoma
  • •
    Leiomyoma of lower esophageal sphincter
  • •
    Extraesophageal neoplasia

    • •
      Thyroid carcinoma
    • •
      Pulmonary carcinoma
    • •
      Mediastinal lymphosarcoma

• Achalasia of lower esophageal sphincter (rare)

• Gastroesophageal intussusception (rare)

Weakness

• Myasthenia (generalized or localized)

• Hypoadrenocorticism

• Esophagitis

• Persistent vomiting

• Hiatal hernia

• Gastroesophageal reflux/anesthesia-associated reflux

• Caustic ingestion (doxycycline, disinfectants, chemicals, etc.)

• Foreign body

• Excess gastric acidity (gastrinoma, mast cell tumor)

• Fungal organisms (e.g., pythiosis)

Spirocerca lupi Infection

 

Myopathies/Neuropathies

• Hypothyroidism

• Systemic lupus erythematosus (SLE)

• Others

Miscellaneous Causes

• Lead poisoning

• Chagas disease

• Canine distemper

• Dermatomyositis (principally in Collies)

• Dysautonomia

• Tetanus

Idiopathic

 

Stomach Disorders

Differential Diagnosis

Gastritis

Acute Gastritis

• Dietary indiscretion

• Dietary intolerance or allergy

• Foreign body

• Drugs and toxins (nonsteroidal antiinflammatory drugs [NSAIDs], corticosteroids, antibiotics, plants, cleaners, bleach, heavy metals)

• Systemic disease (uremia, hepatic disease, hypoadrenocorticism)

• Parasites (Ollulanus spp., Physaloptera spp.)

• Bacterial (bacterial toxins, Helicobacter spp.)

Hemorrhagic Gastroenteritis

 

Chronic Gastritis

• Lymphocytic/plasmacytic gastritis (inflammatory reaction to a variety of antigens such as Helicobacter spp. or Physaloptera rara)

• Eosinophilic gastritis (allergic reactions to food antigens)

• Granulomatous gastritis (e.g., Ollulanus tricuspis)

• Atrophic gastritis

Gastric Outflow Obstruction/Gastric Stasis

• Benign muscular pyloric hypertrophy (pyloric stenosis)

• Gastric antral mucosal hypertrophy

• Foreign body

• Idiopathic gastric hypomotility

• Bilious vomiting syndrome

Gastric Ulceration/Erosion

Iatrogenic

• NSAIDs

• Corticosteroids

• NSAID/corticosteroid combinations

Foreign Body

 

Helicobacter spp.

 

Stress Ulceration

• Hypovolemic shock

• Septic shock

• After gastric dilatation/volvulus

  • •
    Neurogenic shock
• Hyperacidity

  • •
    Mast cell tumor
  • •
    Gastrinoma (rare)
• Other causes

  • •
    Hepatic disease
  • •
    Renal disease
  • •
    Hypoadrenocorticism
  • •
    Inflammatory disease

Infiltrative Disease

• Neoplasia

• Inflammatory bowel disease

• Pythiosis (young dogs, southeastern United States)

Gastric Dilatation/Volvulus

 

Causes of Acute Abdomen

Gastrointestinal (GI) Causes

• Acute pancreatitis

• Gastroenteritis (parvoviral, bacterial, toxic, hemorrhagic gastroenteritis, etc.)

• Gastric dilatation/volvulus

• Intestinal obstruction/intussusception/volvulus

• Colitis

• Obstipation

• Necrosis, rupture, ulceration, or perforation of GI tract

• Surgical wound dehiscence

• Mesenteric torsion

• Duodenocolic ligament entrapment

• Pancreatic abscess

• Pancreatic neoplasia

Hepatobiliary Causes

• Acute hepatitis/cholangiohepatitis

• Biliary obstruction

• Necrotizing cholecystitis

• Hepatic abscess

• Bile peritonitis

• Liver lobe torsion

• Hepatic trauma/rupture

• Hepatobiliary neoplasia

Urogenital Causes

• Urethral or ureteral obstruction/rupture

• Pyelonephritis

• Renal neoplasia

• Acute nephrosis/nephritis

• Cystic, renal, ureteral, or urethral calculi

• Prostatitis/prostatic abscess/prostatic cyst/prostatic neoplasia

• Dystocia

• Pyometra/uterine rupture

• Acute metritis

• Renal abscess

• Testicular torsion

• Ovarian cyst, ovarian neoplasia

• Uterine torsion

• Uroabdomen

• Vaginal rupture

Other Causes

• Penetrating wound, crush injury

• Peritonitis (septic, chemical, urine, bile)

• Mesenteric traction (large masses)/lymphadenitis/lymphadenopathy/volvulus/avulsion/artery thrombosis

• Hemoabdomen (parenchymatous organ rupture)

• Neoplasia

• Splenic torsion/abscess/mass/rupture

• Strangulated hernia

• Adhesions with organ entrapment

• Pansteatitis

• Retroperitoneal hemorrhage

• Evisceration

• Surgical contamination

Small Intestinal Disease

Clinical Findings

• Diarrhea

• Vomiting

• Inappetence/anorexia

• Malabsorption

• Protein-losing enteropathy

• Weight loss

• Dehydration

• Hematemesis

• Melena

• Polyphagia

• Coprophagia

• Abdominal distension

• Abdominal pain

• Borborygmus/flatulence

• Ascites

• Edema

• Shock

• Halitosis

• Polydipsia

• Ileus

Differential Diagnosis

Acute Diarrhea

• Acute enteritis

• Dietary indiscretion

• Enterotoxemia

Infectious Diarrhea

• Canine parvoviral enteritis

• Clostridial disease

• Feline parvoviral enteritis (panleukopenia)

• Canine coronaviral enteritis

• Feline coronaviral enteritis

• Feline leukemia virus–associated panleukopenia

• Feline immunodeficiency virus–associated diarrhea

• Salmon poisoning (Neorickettsia helminthoeca)

• Campylobacteriosis

• Salmonellosis

• Histoplasmosis

• Miscellaneous bacteria (Yersinia enterocolitica, Aeromonas hydrophila, Plesiomonas shigelloides)

• Protothecosis (algae)

Alimentary Tract Parasites

• Roundworms (Toxocara spp.)

• Hookworms (Ancylostoma, Uncinaria spp.)

• Tapeworms (Dipylidium caninum, Taenia spp., Mesocestoides spp.)

• Strongyloides stercoralis (in puppies)

• Coccidiosis

• Cryptosporidia

• Giardiasis

• Trichomoniasis

• Heterobilharzia

Maldigestive Disease

• Exocrine pancreatic insufficiency

Malabsorptive Disease

• Dietary-responsive disease (allergy, intolerance)

• Inflammatory bowel disease (lymphocytic/plasmacytic enteritis canine eosinophilic gastroenteritis)

• Feline eosinophilic enteritis/hypereosinophilic syndrome

• Granulomatous enteritis

• Immunoproliferative enteropathy in Basenjis

• Enteropathy in Shar-Peis

• Antibiotic-responsive enteropathy

Protein-Losing Enteropathy

• Intestinal lymphangiectasia

• Protein-losing enteropathy in Soft-Coated Wheaten Terriers

Irritable Bowel Syndrome

 

Intestinal Obstruction

• Simple intestinal obstruction

• Incarcerated intestinal obstruction

• Mesenteric torsion/volvulus

• Linear foreign object

Intussusception

• Ileocolic

• Jejunojejunal

Short-Bowel Syndrome

 

Neoplasia

• Alimentary lymphoma

• Intestinal adenocarcinoma

• Intestinal leiomyoma/leiomyosarcoma

Breed Susceptibilities, Dogs

• Basenji: lymphocytic/plasmacytic enteritis (immunoproliferative disease)

• Beagle: cobalamin deficiency

• Border Collie: cobalamin deficiency

• German Shepherd: idiopathic antibiotic-responsive small intestinal disease, inflammatory bowel disease (lymphoplasmacytic, eosinophilic)

• Giant Schnauzer: defective cobalamin absorption

• Irish Setter: gluten-sensitive enteropathy

• Lundehund: lymphangiectasia

• Retrievers: dietary allergy

• Rottweiler: increased susceptibility to parvoviral enteritis

• Soft-Coated Wheaten Terrier: protein-losing enteropathy/nephropathy

• Shar-Pei: lymphocytic/plasmacytic enteritis, cobalamin deficiency

• Yorkshire Terrier: lymphangiectasia

• Toy breeds: hemorrhagic gastroenteritis

Large Intestinal Disease

Differential Diagnosis

Inflammation of Large Intestine

• Acute colitis/proctitis

• Chronic colitis

  • •
    Lymphocytic/plasmacytic colitis
  • •
    Eosinophilic enterocolitis
  • •
    Chronic ulcerative colitis
  • •
    Histiocytic ulcerative colitis (Boxers)

• Irritable bowel syndrome

Dietary Intolerance or Food Allergy

 

Parasites

• Whipworms (Trichuris spp.)

• Tritrichomonas spp. (cats)

• Giardiasis

• Hookworms (Ancylostoma spp.)

• Heterobilharzia americanum

Bacterial Colitis

• Clostridial colitis

• Campylobacter colitis

• Escherichia coli

• Salmonell a spp.

• Brachispira pilosicoli

Fungal Colitis

• Histoplasmosis

• Pythiosis

Viral Colitis

• Feline leukemia virus (FeLV)

• Infections secondary to FeLV and feline immunodeficiency virus (FIV)

Algae (Prototheca spp.)

 

Cecocolic Intussusception

 

Rectal Prolapse

 

Neoplasms of Large Intestine

• Adenocarcinoma

• Lymphoma

• Rectal polyps

Constipation

• Pelvic canal obstruction caused by malaligned healing of pelvic fractures

• Benign rectal stricture

• Dietary indiscretion leading to constipation

• Idiopathic megacolon

Ileus

Causes

Physical

• Intestinal obstruction (foreign body, intussusception, neoplasia, granuloma, torsion, volvulus, incarceration in hernia)

• Overdistension by aerophagia

Metabolic

• Uremia

• Diabetes mellitus

• Hypokalemia

• Endotoxemia

Inflammatory

• Parvovirus

• Peritonitis

• Other inflammatory causes

Functional

• Abdominal surgery

• Peritonitis

• Pancreatitis

• Ischemia

Neuromuscular

• Anticholinergic drugs

• Spinal cord injury

• Visceral myopathies/neuropathy

• Dysautonomia

Malabsorptive Diseases

Causes

• Food intolerance or allergy

• Parasitism

  • •
    Giardiasis

• Bacterial overgrowth

• Inflammatory bowel disease

  • •
    Lymphocytic/plasmacytic enteritis
  • •
    Eosinophilic enteritis
  • •
    Idiopathic villous atrophy
  • •
    Purulent enteritis

• Gastrointestinal lymphoma

• Lymphangiectasia

• Obstruction caused by neoplasia, infection, or inflammation

• Portal hypertension

• Pythiosis

• Exocrine pancreatic insufficiency

• Cholestatic liver disease/biliary obstruction

• Brush border enzyme deficiencies

• Brush border transport protein deficiencies

• Hyperthyroidism

• Gastric hypersecretion

Perianal Disease

Differential Diagnosis

• Perineal hernia

• Perianal fistulae

• Anal sacculitis

• Anal sac impaction

• Abscessed anal sac

• Anal sac (apocrine gland) adenocarcinoma

• Perianal gland tumors

  • •
    Adenoma (common)
  • •
    Adenosarcoma (rare)

Protein-Losing Enteropathy

Differential Diagnosis

Gastrointestinal Hemorrhage

• Hemorrhagic gastroenteritis

• Ulceration

• Neoplasia

Endoparasites

• Giardia spp.

• Ancylostoma spp.

• Coccidia

• Others

Inflammation

• Lymphocytic/plasmacytic

• Eosinophilic

• Granulomatous

Infection

• Parvovirus

• Salmonellosis

• Histoplasmosis

• Phycomycosis

Structural

• Intussusception

Neoplasia

• Lymphosarcoma

Lymphangiectasia

• Primary lymphatic disorder

• Venous hypertension (e.g., right heart failure)

• Hepatic cirrhosis

Fecal Incontinence

Causes

Nonneurologic Disease

Colorectal Disease

• Inflammatory bowel disease

• Neoplasia

• Constipation

Anorectal Disease

• Perianal fistula

• Neoplasia

• Surgery (anal sacculectomy, perianal herniorrhaphy, rectal resection and anastomosis)

Miscellaneous

• Decreased mentation

• Old age

• Severe diarrhea

• Irritable bowel disease

Neurologic Disease

Sacral Spinal Cord Disease

• Discospondylitis

• Neoplasia

• Degenerative myelopathy

• Congenital vertebral malformation

• Sacrococcygeal hypoplasia of Manx cats

• Sacral fracture

• Sacrococcygeal subluxation

• Lumbosacral instability

• Lumbrosacral nerve root compression

• Meningomyelocele

• Viral meningomyelitis

• Cauda equina syndrome

• Vertebral fracture

Peripheral Neuropathy

• Trauma

• Penetrating wounds

• Repair of perineal hernia

• Perineal urethrostomy

• Hypothyroidism?

• Diabetes mellitus?

• Dysautonomia

Central Nervous System

• Infectious (distemper, feline infectious peritonitis)

• Neoplasia

• Vascular compromise

SECTION V. Hematologic Disorders

• Anemia

• Coagulopathies, Inherited and Acquired

• Expected Hemostatic Test Results in Selected Diseases

• Leukocyte Disorders

• Platelet Dysfunction

• Splenitis/Splenomegaly

• Thrombocytopenia

Anemia

Hemolytic Anemia

Causes/Triggers of Immune-Mediated Hemolytic Anemia

Infection

Viral

• Feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), feline peritonitis virus (FIP), chronic upper respiratory or gastrointestinal (GI) disease

Bacterial

• Leptospirosis, Mycoplasma haemophilus infection, salmonellosis, acute and chronic infections (e.g., abscess, pyometra, discospondylitis)

Parasitic

• Babesiosis, anaplasmosis, leishmaniasis, dirofilariasis, ehrlichiosis, Ancylostoma caninum, Trichuris vulpis infection, bartonellosis

Immune Disorders

• Systemic lupus erythematosus (SLE)

• Hypothyroidism

• Primary and secondary immunodeficiencies

Drugs/Toxins

• Vaccines

• Sulfonamides

• Methimazole

• Procainamide

• Cephalosporins

• Penicillins

• Propylthiouracil

• Carprofen

• Levamisole

• Griseofulvin

• Bee-sting envenomation

Oxidants

• Acetaminophen

• Phenothiazines

• Vitamin K

• Methylene blue

• Methionine

• Propylene glycol

Inflammation

• Pancreatitis

• Prostatitis/cystitis

Neoplasia

• Leukemias

• Lymphoma

• Multiple myeloma

• Mast cell tumor

• Splenic hemangioma

• Solid tumors

Genetic Predisposition

• American Cocker Spaniel (most common breed), English Springer Spaniel, Old English Sheepdog, Irish Setter, Poodle, Dachshund, Alaskan Malamute, Schnauzer

Differentiating Blood Loss from Hemolytic Anemia

Blood Loss

• Serum or plasma protein concentration normal to low

• Clinical evidence of hemorrhage

• No icterus, hemoglobinemia, spherocytosis, hemosiderinuria, autoagglutination, splenomegaly, or red blood cell (RBC) changes

• Negative direct Coombs test

Hemolysis

• Serum or plasma protein concentration normal to high

• Rarely clinical evidence of hemorrhage

• Icterus common

• Hemoglobinuria/hemoglobinemia

• Spherocytosis

• Hemosiderinuria

• Autoagglutination sometimes seen

• Direct Coombs test usually positive

• Splenomegaly

• RBC changes numerous

Nonregenerative Anemia

Differential Diagnosis

Anemia of Chronic Disease

Erythropoietin-Related Conditions

• Renal disease

• Hypothyroidism

• Hypoadrenocorticism

• Panhypopituitarism

• Growth hormone deficiency

• Reduced oxygen requirement

• Increased oxygen release

Iron Deficiency Anemia

• Chronic inflammation

• Chronic hemorrhage

• Dietary iron deficiency

Marrow Disorders

Toxic Red Cell Aplasia

• Estrogen related

• Phenylbutazone related

• Other drugs

Hyperestrogenism (Iatrogenic, Neoplastic)

 

Infection

• Feline leukemia virus (FeLV)

• Feline immunodeficiency virus (FIV)

• Parvovirus

• Ehrlichiosis

• Babesiosis

• Mycoplasma haemofelis

• Endotoxemia

Immunotherapy

 

Myelofibrosis

• Feline leukemia virus (FeLV) infection

• Pyruvate kinase deficiency anemia

• Idiopathic

Myelophthisic Disease

• Acute leukemias

• Chronic leukemias

• Multiple myeloma

• Lymphoma

• Systemic mast cell disease Malignant histiocytosis

• Metastatic carcinoma

• Histoplasmosis

Myelodysplasia

• Idiopathic

• FeLV/FIV

• Preleukemic syndrome

Pure Red Cell Aplasia

 

Ineffective Erythropoiesis

Macrocytic (rare)

• Intrinsic marrow disease

• Vitamin B₁₂ deficiency

• Folic acid deficiency

Normocytic

• Myelofibrosis

• Intrinsic erythroid disease

Microcytic

• Iron deficiency

• Globin or porphyrin deficiency

Time Related

• Hemolysis or hemorrhage (during the first 3–5 days)

Diagnosis

Nonregenerative Anemias without Other Cytopenias

• Examine bone marrow.

Severe Erythroid Hypoplasia

• Pure red cell aplasia

Normal to Mild Erythroid Hypoplasia

• Inflammatory disease

• Renal disease

• Neoplasia

• Hepatic disease

• Hypothyroidism

• Hypoadrenocorticism

Hypercellular Bone Marrow

• Less than 30% blast forms: consider myelodysplastic syndrome

• Greater than 30% blast forms: consider hemopoietic neoplasia

Nonregenerative Anemias with Leukopenia and/or Thrombocytopenia

• Examine bone marrow.

Panhypoplasia

• Aplastic anemia

Disease Determined by Core Biopsy

• Myelonecrosis

• Myelofibrosis

Hypercellular Bone Marrow

• Less than 30% blast forms: myelodysplastic syndrome

• More than 30% blast forms: hemopoietic neoplasia

Regenerative Anemia

Differential Diagnosis

Hemolysis

• Immune mediated

  • •
    Intravascular
  • •
    Extravascular

Blood Loss Anemia

• Trauma

• Coagulopathy

  • •
    Clotting factor deficiency
  • •
    Disseminated intravascular coagulation (DIC)
  • •
    Platelet disorders
  • •
    Anticoagulant rodenticides

• Endoparasites

• GI blood loss

• Severe ectoparasites (fleas)

Oxidative Injury (Heinz Body)

• Onion ingestion

• Acetaminophen (cats)

• Zinc ingestion (pennies minted after 1982, zinc oxide ointment, zinc-plated bolts and screws)

• Benzocaine ingestion (dogs)

• d-l Methionine (cats)

• Phenolic compounds (mothballs)

• Phenazopyridine (cats)

Erythrocytic Parasites

• Haemobartonella spp.

• Babesia spp.

• Cytauxzoon spp.

Fragmentation (Microangiopathic)

• Disseminated intravascular coagulation (DIC)

• Heartworm disease

• Hemangiosarcoma

• Vasculitis

• Hemolytic-uremic syndrome

• Diabetes mellitus

Other

• Copper toxicity

• Neonatal isoerythrolysis

• Hereditary nonspherocytic hemolytic anemia

• Pyruvate kinase deficiency

• Feline porphyria

• Hemolysis in Abyssinian and Somali cats

Coagulopathies, Inherited and Acquired

Differential Diagnosis

Inherited Clotting Factor Deficiencies

• Hemophilia A (factor VIII deficiency)

• Hemophilia B (factor IX deficiency)

• Factor XII deficiency (Hageman trait) (Miniature and Standard Poodle, Shar-Pei, German Shorthair Pointer, cats)

• Vitamin K–dependent factor deficiency: factors II, VII, IX, X (Devon Rex cats)

• Factor I: hypofibrinogenemia or dysfibrinogenemia (St. Bernard, Borzoi)

• Factor II: hypoprothrombinemia (Boxer, Otterhound, English Cocker Spaniel)

• Factor VII: hypoproconvertinemia (Beagle, Malamute, Boxer, Bulldog, Miniature Schnauzer)

• Factor X deficiency (Cocker Spaniel, Parson Russell Terrier)

• Hemophilia C (factor XI deficiency: English Springer Spaniel, Great Pyrenees, Kerry Blue Terrier)

• Prekallikrein deficiency (Fletcher factor)

Acquired Clotting Factor Deficiency

• Liver disease

  • •
    Decreased clotting factor production
  • •
    Qualitative disorders

• Cholestasis

• Vitamin K antagonists

• Autoimmune disease (lupus anticoagulant)

• Disseminated intravascular coagulation (DIC)

• Neoplasia

Clinical Manifestations of Primary and Secondary Hemostatic Defects

Primary Hemostatic Defects

• Thrombocytopenia and diseases that cause platelet dysfunction such as uremia, von Willebrand disease, monoclonal gammopathies, and vector-borne diseases)—typically see manifestations of superficial bleeding

  • •
    Petechiae, ecchymoses
  • •
    Bleeding from mucosal surfaces (e.g., bleeding from gingiva, melena, hematochezia, epistaxis, hematuria)
  • •
    Bleeding in skin
  • •
    Hematomas rare
  • •
    Prolonged bleeding immediately after venipuncture

Secondary Hemostatic Defects

• Clotting factor deficiencies, rodenticide poisoning, liver disease—typically see manifestations of deep bleeding

  • •
    Petechiae, ecchymoses rare
  • •
    Hematomas common
  • •
    Bleeding into body cavities, joints, muscles
  • •
    Delayed bleeding after venipuncture

Expected Hemostatic Test Results in Selected Diseases

• •Thrombocytopenia—increased buccal mucosal bleeding time (BMBT), decreased platelet count (PLT), normal activated partial thromboplastin time (APTT), normal prothrombin time (PT), normal fibrin degradation products (FDP)
• •Platelet dysfunction (e.g., aspirin treatment)—increased BMBT, normal PLT, increased APTT, normal, PT, normal FDP
• •Intrinsic pathway defect (e.g., hemophilia A or B)—normal BMBT, normal PLT, increased APTT, normal PT, normal FDP
• •Factor VII deficiency—normal BMBT, normal PLT, normal APTT, increased PT, normal, FDP
• •Multiple factor defects (e.g., vitamin K antagonism)—normal BMBT, normal PLT, increased APTT, increased PT, normal FDP
• •Common pathway defect (e.g., factor X deficiency)—normal BMBT, normal PLT, increased APTT, increased PT, normal FDP
• •Disseminated intravascular coagulation (DIC) — increased BMBT, decreased PLT, increased APTT, increased PT, increased FDP
• •von Willebrand disease—increased BMBT, normal PLT, normal APTT, normal PT, normal FDP

Leukocyte Disorders

Differential Diagnosis

• Pelger-Huët anomaly (many breeds of dogs and cats)

  • •
    Neutrophil function not altered

• Chédiak-Higashi syndrome (blue smoke-colored Persian cats)

• Canine leukocyte adhesion deficiency: fatal defect (Irish Setter and Irish Setter crosses)

• Cyclic hemopoiesis (cyclic neutropenia): fatal defect (gray Collies)

• Birman cat neutrophil granulation anomaly: neutrophil function not altered

• Hypereosinophilic syndrome (cats): may eventually be fatal

• Severe combined immunodeficiency of Parson Russell Terriers: fatal defect

• Canine X-linked severe combined immunodeficiency: fatal defect (many breeds)

• Defective neutrophil function in Doberman Pinscher: need frequent antimicrobial therapy

• Immunodeficiency of Shar-Peis

• Immunodeficiency of Weimaraners

• Lysosomal storage diseases (many types described, all rare, many breeds)

Platelet Dysfunction

Differential Diagnosis

Acquired Platelet Dysfunction

Drugs

• Prostaglandin inhibitors (NSAIDs)

• Vaccines

• Antibiotics

• Antifungals

• Phenothiazines

• Aminophylline

• Diltiazem

• Isoproterenol

Secondary to Disease

• Renal disease

• Liver disease

• Myeloproliferative disorders

• Systemic lupus erythematosus (SLE)

• Dysproteinemias

Hereditary

• von Willebrand disease (many breeds)

• Canine thrombopathia (Basset Hound, Foxhound, Spitz)

• Canine thrombasthenic thrombopathia (Otterhound, Great Pyrenees)

• Collagen deficiency diseases/Ehler-Danlos syndrome (many breeds)

Splenitis/Splenomegaly

Differential Diagnosis for Splenomegaly

Splenic Mass (Asymmetric Splenomegaly)

• Nodular hyperplasia (lymphoid, fibrohistiocytic)

• Hematoma

• Neoplasia

  • •
    Hemangiosarcoma
  • •
    Hemangioma
  • •
    Leiomyosarcoma
  • •
    Fibrosarcoma
  • •
    Histiocytic sarcoma
  • •
    Leiomyoma
  • •
    Myelolipoma
  • •
    Metastatic disease

• Abscess

• Extramedullary hematopoiesis

• Granuloma

Uniform Splenomegaly

Congestion

• Drugs

• Portal hypertension

• Right-sided heart failure

• Splenic torsion

Hyperplasia

• Chronic infection

• Inflammatory bowel disease

• Systemic lupus erythematosus (SLE)

• Polycythemia vera

Extramedullary Hematopoiesis

• Chronic anemia

• Immune-mediated hemolytic anemia

• Immune-mediated thrombocytopenia

Neoplasia

• Lymphoma

• Systemic mastocytosis

• Primary mast cell tumor

• Metastatic neoplasia

• Multiple myeloma

• Acute and chronic leukemias

• Malignant histiocytosis

• Polycythemia vera

Nonneoplastic Infiltrative Disease

• Amyloidosis

• Hypereosinophilic syndrome (cats)

Inflammation

• Suppurative

• Sepsis

• Bacterial endocarditis

• Infectious canine hepatitis

• Foreign body

• Penetrating wounds

• Toxoplasmosis

Granulomatous

• Cryptococcosis

• Histoplasmosis

• Mycobacteriosis

• Leishmaniasis

Pyogranulomatous

• Feline infectious peritonitis (FIP)

• Blastomycosis

• Sporotrichosis

Eosinophilic

• Eosinophilic gastroenteritis

• Hypereosinophilic syndrome

• Neoplasia

Lymphoplasmacytic

• Ehrlichiosis

• Hemotropic mycoplasmosis

• Lymphoplasmacytic enteritis

• Pyometra

• Brucellosis

• Anaplasmosis

Necrotic Tissue

• Torsion

• Necrotic center of neoplasms

• Infectious canine hepatitis

• Anaerobic infection

• Systemic calicivirosis

• Tularemia

• Salmonellosis

Infectious Causes

Viral

• Feline leukemia virus (FeLV)

• Feline immunodeficiency virus (FIV)

• Feline infectious peritonitis (FIP)

• Infectious canine hepatitis

Bacterial

• Canine brucellosis

• Mycoplasmosis

• Borreliosis

• Plague

• Tularemia

• Streptococcosis

• Staphylococcosis

• Salmonellosis

• Francisella infection

• Endotoxemia

Fungal

• Cryptococcosis

• Histoplasmosis

• Blastomycosis

Rickettsial

• Ehrlichiosis

• Rocky Mountain spotted fever

• Q fever (Coxiella burnetii)

• Mycoplasma haemofelis

Protozoal

• Toxoplasmosis

• Cytauxzoonosis (cat)

• Babesiosis (Babesia canis and B. gibsoni)

• Leishmaniasis (dog)

Thrombocytopenia

Differential Diagnosis

Increased Platelet Destruction/Sequestration/Utilization

• Immune-mediated thrombocytopenia

• Drug-induced thrombocytopenia

• Infectious (Anaplasma spp., Bartonella spp., sepsis)

• Microangiopathy

• Disseminated intravascular coagulation

• Neoplasia (immune-mediated, microangiography)

• Live viral vaccine–induced thrombocytopenia

• Hemolytic uremic syndrome/thrombotic thrombocytopenic purpura

• Vasculitis

• Splenomegaly

• Splenic torsion

• Endotoxemia

• Acute hepatic necrosis

• Hemorrhage

Decreased Platelet Production

• Drug-induced megakaryocytic hypoplasia (estrogen, phenylbutazone, melphalan, lomustine, β-lactams)

• Myelophthisis

• Idiopathic bone marrow aplasia

• Retroviral infection (FeLV/FIV)

• Immune-mediated megakaryocytic hypoplasia

• Cyclic thrombocytopenia

• Idiopathic bone marrow aplasia

• Ehrlichiosis

SECTION VI. Immunologic and Immune-Mediated Disorders

• Autoimmune Skin Diseases

• Immune-Mediated Disease

• Immune System Components

• Mechanisms of Immunopathologic Injury

• Organ Systems Affected by Autoimmune Disorders in the Dog and Cat

• Systemic Lupus Erythematosus (SLE)

Autoimmune Skin Diseases

Differential Diagnosis

Generalized Pustular/Crusting Dermatosis

• Pemphigus foliaceus (PF) (nose, ear pinna, and footpad typically affected)

• Superficial pustular drug reactions (nasal and footpad lesions may be absent)

• Others: rare presentation—systemic lupus erythematosus (SLE), sterile eosinophilic pustulosis, linear immunoglobulin A (IgA) pustular dermatosis, subcorneal pustular dermatosis

Focal Pustular/Crusting Dermatosis

• Face, footpads: PF

• Face and ears only: PF (early), pemphigus erythematosus (PE), drug eruptions, lupus erythematosus

• Nasal only: discoid lupus erythematosus (DLE), PF (early), PE

Mucocutaneous and Mucosal Ulcerations

• Pemphigus vulgaris (may also have oral lesions)

• Mucous membrane bullous pemphigoid

• Epidermolysis bullosa acquisita

• Erythema multiforme (target lesions, cutaneous lesions)

• Bullous SLE

• Drug reactions

• Linear IgA bullous dermatosis, toxic epidermal necrolysis (rare)

Nonmucosal Ulcerations (Axillae, Inguinae, Pinnae, Other Haired Areas)

• Bullous pemphigoid

• Epidermolysis bullosa acquisita

• Linear IgA bullous dermatosis

• Bullous SLE

• Canine vesicular cutaneous lupus erythematosus (idiopathic ulcerative dermatosis of Collies, Shetland Sheepdogs)

• Erythema multiforme (EM)

• Toxic epidermal necrolysis

• Drug eruptions

• Pemphigus vulgaris

Depigmenting Skin Diseases

• Nasal only: DLE, vitiligo-like syndrome, uveodermatologic syndrome, early PF or PE

• Nose, footpad, lip, eyelid, mucocutaneous area: uveodermatologic syndrome (uveitis also)

• Haircoat or skin: idiopathic leukotrichia or leukoderma

Miscellaneous

• Focal alopecia: alopecia areata, rabies vaccine, focal vasculitis

• Widespread noninflammatory alopecia: alopecia areata, pseudopelade

• Erythematous target lesions: erythema multiforme

• Nodular ulcerative lesions: nodular panniculitis

• Purpura, hemorrhage, punched-out lesions

• Ear margin necrosis, dependent edema: vasculitis, proliferative necrotizing otitis of kittens, cryoglobulinemia and cryofibrinogenemia, proliferative thrombovascular necrosis of the pinnae

Immune-Mediated Disease

Laboratory Diagnosis

Direct Coombs Test

• Immune-mediated hemolytic anemia

• Hemolytic anemia in systemic lupus erythematosus (SLE)

Antiplatelet Antibodies

• Immune-mediated thrombocytopenia

Antineutrophil Antibodies

• Immune-mediated neutropenia

Thyroxin and Thyroglobulin Autoantibodies

• Hypothyroidism

Acetylcholine Receptor Autoantibodies

• Myasthenia gravis

2M Myofiber Autoantibodies

• Masticatory muscle myositis

Antinuclear Antibody

• SLE

• Chronic antigenic stimulation

Rheumatoid Factor

• Rheumatoid arthritis (RA)

Direct Immunofluorescence

• Antibody-complement deposition

Differential Diagnosis for Immune-Mediated Arthritis

Erosive Immune-Mediated Arthritides

• RA (dog, rarely in cat)

• Periosteal proliferative polyarthritis (cat, rarely in dog)

Nonerosive Immune-Mediated Arthritides

• Idiopathic polyarthritis

  • •
    Type I: uncomplicated idiopathic arthritis (most common)
  • •
    Type II: idiopathic arthritis associated with infection remote from joints—respiratory tract, tonsils, conjunctiva (chlamydia in cats), urinary tract, uterus, skin, oral cavity
  • •
    Type III: idiopathic arthritis associated with gastroenteritis
  • •
    Type IV: idiopathic arthritis associated with malignant neoplasia—squamous cell carcinoma, heart base tumor, leiomyoma, mammary carcinoma, myeloproliferative disease (cats)

• SLE

• Drug-induced polyarthritis

  • •
    Sulfas, lincomycin, erythromycin, cephalosporins, penicillins, trimethoprim-sulfa (especially Doberman Pinscher)

• Vaccination reaction

• Polyarthritis/polymyositis syndrome

• Polyarthritis/meningitis syndrome

• Familial renal amyloidosis in Chinese Shar-Peis

• Polyarthritis in adolescent Akitas

• Polyarthritis nodosa (inflammatory condition of small arteries—histopathologic diagnosis)

Immune System Components

Function

Humoral immunity

B Lymphocytes and Plasma Cells

• Production of immunoglobulins

Cellular Immunity

T Lymphocytes

• Production of lymphokines

• Helper T cells

  • •
    Stimulate immune reactivity
• Suppressor T cells

  • •
    Suppress immune reactivity

• Antibody-dependent cell-mediated cytotoxicity

• Natural killer cells

  • •
    Direct cytotoxicity

Phagocytic Cells

Mononuclear Phagocytic Cells

• Antigen presentation

• Phagocytosis of particles

Neutrophils and Eosinophils

• Phagocytosis of particles

• Antibody-dependent cell-mediated cytotoxicity

Mechanisms of Immunopathologic Injury

Type I (immediate)

• •Humoral immune system (T-helper cells and B cells), IgE, mast cells, inflammatory mediators)
• •Skin, respiratory tract, GI tract commonly affected
• •Examples include acute anaphylactic reaction, atopy, allergic bronchitis, feline asthma

Type II (cytotoxic)

• •Humoral immune system (IgG and IgM)
• •Hematologic systems, neuromuscular junctions, and skin commonly affected
• •Examples include immune-mediated hemolytic anemia, immune-mediated thrombocytopenia, myasthenia gravis, pemphigus foliaceous

Type III (immune complex)

• •Soluble immune complexes
• •Kidney, joints, and skin commonly affected
• •Examples include glomerulonephritis, systemic lupus erythematosus, rheumatoid arthritis

Type IV (delayed type)

• •Sensitized T lymphocytes, cytokines, neutrophils, and macrophages
• •Endocrine glands, muscle commonly affected
• •Examples include lymphocytic thyroiditis, myositis

Organ Systems Affected by Autoimmune Disorders in the Dog and Cat

Differential Diagnosis

Hematologic

• •Immune-mediated hemolytic anemia
• •Pure red cell aplasia
• •Immune-mediated thrombocytopenia
• •Idiopathic neutropenia

Joints (seeDifferential Diagnosis for Immune-Mediated Arthritis)

 

Skin (seeAutoimmune Skin Diseases)

 

Eye

• •Uveitis
• •Retinitis

Kidney

• •Glomerulonephritis

Respiratory Tract

• •Allergic rhinitis
• •Allergic bronchitis (asthma)
• •Pulmonary infiltrates with eosinophils

Gastrointestinal Tract

• •Feline stomatitis, gingivitis
• •Lymphocytic, plasmacytic enteritis
• •Anal furunculosis (perianal fistula)

Neurologic System

• •Myasthenia gravis
• •Myositis
• •Polyradiculoneuritis
• •Granulomatous meningoencephalitis
• •Polyarteritis

Endocrine Glands

• •Thyroiditis (hypothyroidism)
• •Adrenalitis (hypoadrenocorticism)
• •Insulitis (diabetes mellitus)

Multisystemic Immune Disease

• •Systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE)

Organs and Tissues Affected

• Red blood cells

  • •
    Immune-mediated hemolytic anemia
  • •
    Pure red cell aplasia
• Platelets

  • •
    Immune-mediated thrombocytopenia
• Glomeruli

  • •
    Glomerulonephritis
• Synovium

  • •
    Nonerosive polyarthritis
• Blood vessels

  • •
    Vasculitis
• Epidermis

  • •
    Dermatitis
• Neutrophils

  • •
    Immune-mediated neutrophilia
• Clotting factors

  • •
    Coagulopathy
• Central nervous system

  • •
    Seizures, focal signs
• Skeletal muscle/nerve end plate

  • •
    Polymyositis
  • •
    Polyneuritis
  • •
    Myasthenia gravis

Criteria for Diagnosis in Dogs and Cats

SLE is diagnosed when three or more of the following criteria are manifested simultaneously or at any time:

• Antinuclear antibodies (ANAs)

  • •
    Abnormal ANA titer in the absence of drugs or infectious or neoplastic conditions known to be associated with abnormal titers
• Cutaneous lesions

  • •
    Depigmentation, erythema, erosions, ulcerations, crusts, scaling, with biopsy findings consistent with SLE
• Oral ulcers

  • •
    Oral or nasopharyngeal ulceration, usually painless
• Arthritis

  • •
    Nonerosive, nonseptic arthritis involving two or more peripheral joints
• Renal disorders

  • •
    Glomerulonephritis or persistent proteinuria in the absence of urinary tract infection
• Anemia/thrombocytopenia

  • •
    Hemolytic anemia/thrombocytopenia in the absence of offending drugs
• Leukopenia

  • •
    Low total white cell count
• Polymyositis or myocarditis

  • •
    Inflammatory disease of skeletal or cardiac muscles
• Serositis

  • •
    Presence of a nonseptic inflammatory cavity effusion (abdominal, pleural, or pericardial)
• Neurologic disorders

  • •
    Seizures or psychosis in the absence of known disorders
• Antiphospholipids

  • •
    Prolongation of activated partial thromboplastin time (APTT) that fails to correct with a 1:1 mixture of patient's and normal plasma, in the absence of heparin or fibrin degradation products (FDPs)

SECTION VII. Infectious Disease

• Anaplasmosis, Canine

• Bacterial Infections, Systemic

• Bartonellosis, Canine

• Bartonellosis, Feline

• Anaplasmosis

• Anaplasma Platys

• Ehrlichiosis, Canine

• Influenza, Canine

• Neorickettsiosis Canine

• Mycoses, Systemic

• Polysystemic Protozoal Diseases

• Rocky Mountain Spotted Fever

• Sepsis and Systemic Inflammatory Response Syndrome (SIRS)

• Vaccines, Recommended Core vs. Noncore

• Viruses, Canine

• Viruses, Feline

Anaplasmosis, Canine

Clinical Signs

• Infection may be subclinical

• Fever

• Depression

• Inappetence

• Scleral injection

• Lameness, stiffness, reluctance to move

• Coughing (soft and nonproductive)

• Lymphadenopathy

• Splenomegaly

• Neutrophilic polyarthritis (rare)

• CNS signs?

• Vomiting/diarrhea

• May be more susceptible to other infections

Laboratory Abnormalities

• Thrombocytopenia

• Lymphopenia

• Eosinopenia

• Mild regenerative anemia

• Hypoalbuminemia

• Mild to moderately elevated hepatic enzymes

Bacterial Infections, Systemic

Differential Diagnosis

Leptospirosis

• Hepatic dysfunction, renal dysfunction, fever, anterior uveitis, icterus

• Coagulation abnormalities, vomiting/diarrhea, icterus, polyuria/polydipsia, anorexia

• Some cases may be subclinical

Borreliosis (Lyme Disease)

• Fever, inappetence/lethargy, lymphadenopathy, polyarthritis

• Glomerulonephritis/acute, progressive renal failure, mild dermatologic lesions

• Meningitis/encephalitis (rare), myocarditis

Mycobacteriosis

• Often asymptomatic, skin lesions, dermal nodules, draining tracts, lymphadenopathy, bronchopneumonia, pulmonary nodules, hilar lymphadenopathy, vomiting, diarrhea secondary to intestinal malabsorption, feline leprosy

Brucellosis (Dogs)

• Clinical signs may be mild to absent

• Fever, lymphadenopathy

• Epididymitis, scrotal enlargement, scrotal dermatitis, infertility in males

• Abortion, early embryonic death, fetal resorption, in pregnant bitches

• Discospondylitis

• Rarely uveitis, glomerulonephritis, meningoencephalitis

Tetanus

• Localized tetanus, especially cats; stiffness in a muscle of limb

• Generalized tetanus stiff gait, outstretched or dorsally curved tails, extreme muscle rigidity, hypersensitivity to touch, light, and sounds

• Ears erect, lips drawn back (sardonic grin), protrusion of globe, enophthalmos

• Trismus (lockjaw), laryngeal spasm, regurgitation, megaesophagus leading to aspiration pneumonia, seizures

Botulism

• Generalized lower motor neuron and parasympathetic dysfunction, cranial nerve signs, mentation is normal

• Quadriplegia, megaesophagus, respiratory paralysis; may lead to death

Feline Plague (Yersinia pestis)

• Spread by fleas

• May show signs of bubonic, septicemic, and pneumonic plague

• Depression

• Cervical swellings, draining tracts

• Dyspnea or cough

Mycoplasmosis/Ureaplasmosis (Cats)

• Conjunctivitis, sneezing, mucopurulent nasal discharge, coughing, dyspnea, fever, lameness, swollen joints, subcutaneous abscessation

Members of the Order Rickettsiales of Clinical Importance in Dogs and Cats

Rickettsioses (Spotted Fever Group Rickettsiae)

• Rickettsia rickettsii

• Species of the following tick genera transmit spotted-fever group agents: Dermacentor, Rhipicephalus, Haemaphysalis, and Amblyomma

Ehrlichiosis (Canine)

• Ehrlichia canis, E. chaffeensis, E. ewingii, E. muris, and E. ruminantium

Anaplasmosis (Canine and Feline)

• Anaplasma phagocytophilium

• Anaplasma platys (canine cyclic thrombocytopenia: mildly pathogenic)

Neorickettsiosis

• Neorickettsia helminthoeca, N. risticii

Bartonellosis, Canine

Clinical Findings

• •Many species of Bartonella are suspected to cause disease in dogs (e.g., B. vinsonii, B. henselae, B. clarridgeae, B. elizabethae)
• •Fever
• •Endocarditis, myocarditis, arrhythmias
• • Epistaxis
• •Intermittent lameness
• •Bone pain
• •Granulomatous lymphadenitis
• •Dermatologic lesions/cutaneous vasculitis
• •Anterior uveitis
• •Polyarthritis
• •Meningoencephalitis
• •Immune-mediated hemolytic anemia
• •Thrombocytopenia
• •Eosinophilia
• •Peliosis hepatitis
• •Granulomatous hepatitis
• •Chronic weight loss

Bartonellosis, Feline

Subclinical Disease in Most Cats

• Uveitis?

• Endocarditis?

Anaplasmosis

• Anaplasma phagocytophilum, formally known as Ehrlichia equi, E. phagocytophila

Cause of Canine Granulocytic Ehrlichiosis

Clinical Signs

• Fever

• Depression

• Inappetence

• Scleral injection

• Lameness/polyarthritis

• Coughing

• Lymphadenopathy

• Splenomegaly

• Vomiting/diarrhea

• Lymphopenia, eosinopenia, mild nonregenerative anemia

• Hypoalbuminemia, elevated hepatic enzymes

Anaplasma Platys

Cause of Canine Thrombocytic Anaplasmosis

• Forms morula that can be visualized in platelets

Clinical Signs

• Majority of cases in United States have been mild or subclinical

• More severe signs in European or South American cases include:

  • •
    Fever
  • •
    Splenomegaly
  • •
    Hemorrhage

Ehrlichiosis, Canine

Clinical Findings

Acute

• Fever

• Anorexia/weight loss

• Depression

• Serous or purulent oculonasal discharge

• Lymphadenopathy/splenomegaly

• Peripheral edema

• Petechial and ecchymotic hemorrhages

• Neurologic signs (ataxia, seizures, vestibular signs, hyperesthesia, cranial nerve defects)

• Dyspnea

• History of recent or present tick bite

• Thrombocytopenia

• Leukopenia followed by leukocytosis and monocytosis

• Low-grade nonregenerative anemia, unless hemorrhage

• Variable Ehrlichia titer, polymerase chain reaction (PCR) positive

Subclinical

• No clinical abnormalities apparent

• Hyperglobulinemia, thrombocytopenia, neutropenia, lymphocytosis, monocytosis

• Positive Ehrlichia titer, PCR positive

Chronic

• Depression

• Pale mucous membranes

• Weight loss

• Abdominal pain

• Splenomegaly

• Epistaxis, retinal hemorrhage, petechia and ecchymoses, melena, hematochezia, hematuria, and other examples of hemorrhage

• Lymphadenopathy

• Stiffness, swollen/painful joints, polymyositis

• Hepatomegaly

• Dyspnea, interstitial or alveolar lung infiltrates

• Perivascular retinitis, hyphema, retinal detachment, anterior uveitis, corneal edema

• Seizures, paresis, meningeal pain, cranial nerve deficits

• Arrhythmias

• Polyuria/polydipsia

• Secondary opportunistic infection (viral papillomatosis, protozoal infections, bacteriuria)

• Monocytosis, lymphocytosis, thrombocytopenia, nonregenerative anemia, hyperglobulinemia, hypoalbuminemia, hypocellular bone marrow, proteinuria, polyclonal or monoclonal gammopathy, nonseptic suppurative polyarthritis, cerebrospinal fluid (CSF) mononuclear pleocytosis

• Increased alanine aminotransferase (ALT) and alkaline phosphatase (ALP)

• Positive Ehrlichia titer, PCR positive

Influenza, Canine

Clinical Features

• •Most outbreaks in group housed dogs (race tracks, animal shelters)
• •Individual pets often had a recent history of exposure to other dogs
• •Mild form may cause a harsh cough similar to cough heard with infectious tracheobronchitis
• •More commonly cough is soft and moist, cough may persist for as long as a month
• •Fever
• •Mucopurulent nasal discharge
• •Increased respiratory rate progressing to respiratory distress
• •May progress to overt pneumonia
• •Mortality rate less than 5%. Very young and very old are most at risk

Neorickettsiosis Canine

• Neorickettsia helminthoeca (salmon poisoning disease)

• Restricted to western slopes of Cascade Mountains from northern California to southern Vancouver Island

• Vector is a fluke Nanophyetus salmincola. Dogs become infected from ingesting parasitized fish.

Clinical Signs

• Fever

• Anorexia/weight loss

• Depression

• Lymphadenopathy

• Vomiting

• Diarrhea

• Hematochezia

• Neutrophilia with left shift, lymphopenia, monocytosis, thrombocytopenia

• Electrolyte derangements, elevated hepatic enzymes, hypoalbuminemia

• Neorickettsia risticii

• Cause of equine Potomac horse fever

• Vector is suspected to be a fluke Acanthatrium oregonense

• Has been identified by culture and PCR in dogs with the following signs:

• Lethargy

• Intermittent vomiting

• Bleeding tendencies

• Polyarthritis

• Neurologic signs

• Dependent edema

• Anemia

• Thrombocytopenia

Mycoses, Systemic

Clinical Findings

Blastomycosis

• Restricted primarily to Mississippi, Ohio, Missouri, Tennessee, and St. Lawrence River valleys plus the southern Great Lakes and the southern Mid-Atlantic states

• Sporting breeds predisposed because of greater exposure, males more than females

• Anorexia, depression, weight loss, cachexia, fever, mild to severe dyspnea, cyanosis, cough, chylothorax, diffuse lymphadenopathy, papules, plaques and ulcerative nodules, paronychia, chorioretinitis, conjunctivitis, keratitis, iridocyclitis, anterior uveitis, subretinal granulomas, retinal detachment, secondary glaucoma, lameness from osteomyelitis, splenomegaly

• Radiographically, infiltrative bronchointerstitial and alveolar disease, hilar lymphadenopathy

Histoplasmosis

• Restricted primarily to Mississippi, Missouri, and Ohio River valleys and Mid-Atlantic states

• Sporting breeds predisposed because of greater exposure

• Common clinical signs include anorexia, fever, depression, weight loss, cough, dyspnea, diarrhea (large bowel diarrhea most often, may see protein-losing enteropathy), hepatosplenomegaly, icterus, ascites, and lymphadenopathy.

• Less common signs include lameness secondary to osteomyelitis or polyarthritis, chorioretinitis, central nervous system (CNS) disease, and cutaneous lesions.

Differential Diagnosis for Gastrointestinal Signs Seen in Dogs and Cats with Histoplasmosis

Large Intestinal Disease

• Diet-Associated Colitis

  • •
    Dietary hypersensitivity
  • •
    Foreign material–induced colitis
• Idiopathic Colitis

  • •
    Lymphocytic-plasmacytic colitis
  • •
    Eosinophilic colitis
  • •
    Granulomatous colitis
  • •
    Histiocytic ulcerative colitis of Boxer dogs
  • •
    Suppurative colitis
• Parasitic and Protozoal Colitis

  • •
    Trichuriasis (whipworm)
  • •
    Ancylostomiasis (hookworm)
  • •
    Entamebiasis
  • •
    Balantidiasis
  • •
    Giardiasis
• Bacterial colitis

  • •
    Salmonellosis
  • •
    Campylobacter jejuni
  • •
    Yersinia enterocolitica, Y. pseudotuberculosis
  • •
    Mycobacteria
  • •
    Clostridium perfringens, C. difficile
• Fungal colitis

  • •
    Candidiasis
  • •
    GI pythiosis
  • •
    Protothecosis

• Cecocolic or ileocolic intussusception

• Pancreatitis-associated colitis

Small Intestinal Disease

• Idiopathic inflammatory bowel disease

  • •
    Lymphocytic-plasmacytic enteritis
  • •
    Eosinophilic enteritis
  • •
    Granulomatous enteritis

• Intestinal lymphosarcoma

• Parasitic enteritis

  • •
    Ancylostomiasis
  • •
    Toxocariasis
  • •
    Chronic giardiasis
• Infectious enteritis

  • •
    Small intestinal bacterial overgrowth
  • •
    GI pythiosis

• Lymphangiectasia

• Exocrine pancreatic insufficiency

• Partial intestinal obstruction

• Chronic enteropathy of Shar-Peis

• Immunoproliferative enteritis of Basenjis

Coccidioidomycosis

• Primarily southwestern United States, California, Mexico, Central and South America

• Common clinical signs include lameness with swollen and painful joints and bones, cough, dyspnea, anorexia, weakness, pleural effusion, and cutaneous lesions over infected bones.

• Less common signs include myocarditis, icterus, renomegaly, splenomegaly, hepatomegaly, orchitis, epididymitis, keratitis, iritis, granulomatous uveitis, glaucoma, seizures, ataxia, and central vestibular disease.

Cryptococcosis

• Found worldwide, more common in southern United States, most common in cats

• Common clinical signs include upper respiratory signs, unilateral to bilateral nasal discharge, soft masses in nasal cavity or over bridge of nose, ulcerative skin lesions, lymphadenopathy, granulomatous chorioretinitis, and retinal detachment.

• Less common signs include fever, lung involvement, CNS involvement caused by invasion through cribriform plate, depression, seizures, circling, ataxia, blindness, head pressing, and paresis.

Aspergillosis

• Dogs affected more often than cats

• Nasal turbinate destruction, frontal sinus osteomyelitis, mucoid to hemorrhagic nasal discharge, epistaxis

• May lead to masticatory muscle atrophy and CNS disease by erosion through cribriform plate

• In rare cases, disseminates and causes multiple-organ disease

Pythiosis, Lagenidiosis (Pythium insidiosum, Lagenidium giganteum)

• Severe, often fatal, chronic gastrointestinal and cutaneous diseases

Zygomycosis (Multiple Fungi in Class Zygomycetes)

• Nasopharyngeal involvement, poorly responsive to therapy

Differential Diagnosis for Systemic Manifestations

• Multisystemic granulomatous, neoplastic, and immune-mediated diseases must be differentiated from disseminated systemic mycoses.

Differential Diagnosis for Nodular Skin Disease

Bacteria Skin Disease

• •Actinomycosis
• •Mycobacteriosis
• •Botryomycosis
• •Brucellosis
• • Rhodococcus equi infection
• • Bartonella vinsonii subsp. Berkhoffi infection

Mycotic and Miscellaneous Infectious Skin Disease

• •Cryptococcosis
• •Blastomycosis
• •Coccidioidomycosis
• •Sporotrichosis
• •Basidiobolomycosis
• •Conidiobolomycosis
• •Phaeohyphomycosis
• •Hyalohyphomycosis
• •Eumycotic mycetoma
• •Dermatophytic mycetoma
• •Protothecosis
• •Pythiosis
• •Lagenidiosis
• •Nodular leishmaniasis

Noninfectious Pyogranulomatous Skin Disease

• •Foreign body reaction
• •Idiopathic nodular panniculitis
• •Sebaceous adenitis (nodular form)
• •Canine cutaneous sterile pyogranulomatous/granuloma syndrome

Neoplasia

• •Squamous cell carcinoma
• •Cutaneous lymphoma
• •Mycosis fungoides (cutaneous T-cell lymphoma)
• •Cutaneous histiocytosis

Miscellaneous Diseases

• •Systemic lupus erythematosus
• •Systemic vasculitis
• •Cutaneous embolic disease

Differential Diagnosis for Chorioretinitis, Exudative Retinal Detachment, and Panophthalmitis

Fungal

• •Blastomycosis
• •Cryptococcosis
• •Coccidioidomycosis
• •Geotrichosis
• •Histoplasmosis
• •Aspergillosis

Neoplasia

• •Lymphosarcoma
• •Metastatic neoplasia

Miscellaneous Infectious Causes

• •Protothecosis
• •Brucellosis
• •Toxoplasmosis
• • Neosporum caninum infection
• •
  Leishmaniasis

  • Lymphadenopathy must be differentiated from numerous causes including lymphosarcoma, other fungal infections, rickettsial diseases, brucellosis, mycobacteriosis, protothecosis, and leishmaniasis.
  • Solitary bone lesions must be differentiated from primary or metastatic neoplasia and other fungal or bacterial osteomyelitis.

Polysystemic Protozoal Diseases

Clinical Findings

Feline Toxoplasmosis

• Acute toxoplasmosis: may induce a self-limiting, small bowel diarrhea

• Disseminated toxoplasmosis: overwhelming intracellular replication of tachyzoites after primary infection—depression, anorexia, fever, hypothermia, peritoneal effusion, icterus, dyspnea, death—coinfection with feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), feline infectious peritonitis (FIP), and others may predispose to disseminated toxoplasmosis

• Chronic toxoplasmosis: anterior or posterior uveitis, fever, muscle hyperesthesia, weight loss, anorexia, seizures, ataxia, icterus, diarrhea, pancreatitis

Canine Toxoplasmosis

• Respiratory, gastrointestinal, neuromuscular signs: fever, vomiting, diarrhea, dyspnea, icterus, ataxia, seizures, tremors, cranial nerve deficits, paresis, paralysis, myositis, lower motor neuron disease, myocardial disease, chorioretinitis, anterior uveitis, iridocyclitis, optic neuritis (ocular lesions less common in dogs than cats)

Neosporosis

• Most common in neonates but can be seen at any age

• Ascending paralysis, hyperextension of hind limbs, muscle atrophy, polymyositis, multifocal CNS disease, myocarditis, dysphagia, ulcerative dermatitis, pneumonia, hepatitis

Babesiosis

• Anemia, fever, pale mucous membranes, tachycardia, tachypnea, depression, anorexia, weakness, icterus, petechiae, hepatosplenomegaly, disseminated intravascular coagulation (DIC), metabolic acidosis, renal disease

Cytauxzoonosis

• Fever, anorexia, dyspnea (pneumonitis), depression, icterus, pale mucous membranes, death

Hepatozoonosis (Hepatozoon canis and H. americanum)

• Most common in puppies and immunosuppressed dogs, but H. americanum can be primary

• Fever, weight loss, severe hyperesthesia, anorexia, anemia, depression, oculonasal discharge, bloody diarrhea

Leishmaniasis

• Weight loss, normal to increased appetite, polyuria/polydipsia, muscle wasting, depression, vomiting, diarrhea, cough, epistaxis, sneezing, melena, splenomegaly, facial alopecia, rhinitis, dermatitis, icterus, swollen and painful joints, uveitis, conjunctivitis

• Dermatologic lesions include hyperkeratosis, scaling, mucocutaneous ulcers, and intradermal nodules on muzzle, ears, and footpads.

American Trypanosomiasis (Trypanosoma cruzi)

• Acute infection: myocarditis, heart failure—lymphadenopathy, pale mucous membranes, tachycardia, pulse deficits, hepatomegaly, abdominal distension, anorexia, diarrhea, neurologic signs

• Chronic infection: Those that survive acute infection may present with chronic dilative cardiomyopathy—right-sided heart failure, conductive disturbances, supraventricular arrhythmias.

Rocky Mountain Spotted Fever

Clinical Findings

• Depression/lethargy

• Fever

• Anorexia

• Myalgia/arthralgia

• Lymphadenopathy

• Vestibular deficits

• Conjunctivitis/scleral congestion/hyphema/iridal and retinal hemorrhage

• Pneumonitis/dyspnea/cough

• Abdominal pain

• Edema of face and extremities

• Epistaxis

• Melena

• Hematuria

• Anterior uveitis

• Rash/petechiae

• Nausea/vomiting

• Diarrhea

• Vasculitis/thrombocytopenia/disseminated intravascular coagulation (DIC)

• Hyperesthesia/spinal cord signs

• Seizures

• Cardiac arrhythmias

• Icterus

• Acute renal failure

• Coma/stupor

• Polyuria/polydipsia

Sepsis and Systemic Inflammatory Response Syndrome (SIRS)

Definitions

• Bacteremia: the presence of viable bacteria in the bloodstream

• Sepsis: infection-induced systemic inflammation

• Severe sepsis: organ dysfunction and manifestations of hypoperfusion or hypotension secondary to sepsis

• Septic shock: hypotension secondary to sepsis, not responsive to intravenous (IV) fluid therapy

• SIRS: systemic inflammation caused by either infectious or noninfectious processes. Diagnosis of SIRS is based on fulfillment of at least two of four criteria (tachycardia, tachypnea, hypothermia, or hyperthermia and either leucocytosis, leucopenia, or bands)

• Multiple organ dysfunction syndrome (MODS): altered function of two or more organs secondary to SIRS such that homeostasis cannot be maintained without intervention

• Acute respiratory distress syndrome (ARDS): a pulmonary inflammatory disorder characterized by noncardiogenic pulmonary edema, neutrophilic inflammation, and hypoxemia

Noninfectious Causes of SIRS

• Pancreatitis

• Tissue trauma

• Heat stroke

• Ischemia

• Burns

• Pansystemic neoplasia

Infectious Causes of SIRS (Sepsis)

• Peritonitis

• Pyometra

• Prostatitis

• Prostatic abscess

• Pyelonephritis

• Pneumonia

• Pyothorax

• Gastroenteritis

• Endocarditis

• Nosocomial infections (IV catheters, urinary catheters, etc.)

Clinical Findings of Sepsis and SIRS

• Fever or hypothermia

• Tachycardia, tachypnea

• Neutrophilia with left shift or leukopenia

• Anemia

• Depression

• Bounding or diminished pulses

• Brick-red mucus membranes or pallor

• Hypothermia

• Thrombocytopenia

• Hypoalbuminemia, hypoglycemia

• Disseminated intravascular coagulation (DIC)

• Bilirubinemia

• Elevated hepatic enzymes

• Azotemia

• Oliguria

• Lactic acidosis

• Hypoxemia

• Signs related to underlying condition

Vaccines, Recommended Core vs. Noncore

Core Vaccines for Dogs

• •Distemper
• •Parvovirus
• •Adenovirus-2
• •Rabies

Core Vaccines for Cats

• •Parvovirus (panleukopenia)
• •Herpesvirus-1
• •Calicivirus
• •Rabies

Noncore Vaccines for Dogs

• Need determined by individual clinician after assessment of patient risk

  • •
    Bordetellosis
  • •
    Parainfluenza
  • •
    Canine influenza
  • •
    Leptospirosis
  • •
    Lyme borreliosis
  • •
    Crotalus atrax
  • •
    Porphyromonas spp.

Noncore Vaccines for Cats

• Need determined by individual clinician after assessment of patient risk

  • •
    Feline leukemia virus (FeLV)
  • •
    Feline immunodeficiency virus (FIV)
  • •
    Chlamydophila felis (formally, Chlamydia psittaci)
  • •
    Bordetellosis

Viruses, Canine

Common Viral Agents of Diseases of Dogs

Parvovirus

• May be asymptomatic or fulminant disease

• Anorexia, lethargy, fever, vomiting, hemorrhagic diarrhea, myocarditis (rare)

• Worse in very young and parasitized puppies

• Neutropenia, hypoalbuminemia, severe dehydration, secondary septicemia

Coronavirus

• Diarrhea (infrequently blood in feces), vomiting, anorexia, lethargy, often self-limiting

• Canine respiratory coronavirus, part of “kennel cough” complex

• Coughing, sneezing, nasal discharge

• Canine pancytotropic coronavirus

• Severe clinical disease in puppies and juvenile dogs

• Fever, lethargy, anorexia, vomiting, hemorrhagic diarrhea, ataxia, seizures

Rotavirus

• Vomiting, diarrhea (rarely bloody), anorexia, typically recover after 5–7 days

Adenovirus Type 1 (Infectious Canine Hepatitis)

• Fever, anorexia, lethargy, depression, abdominal pain, pale mucous membranes, tonsillitis, pharyngitis, coughing, hepatomegaly

• Severe cases: coagulation abnormalities, petechiae, ecchymosis, DIC, rarely icterus, hepatic encephalopathy

• Anterior uveitis and glomerulonephritis secondary to immune complex deposition

Canine Distemper Virus (See the next section)

 

Canine Influenza A Subtype H3N8 Virus

• Acute onset of coughing, sneezing, nasal discharge, ocular discharge

• Lowgrade fever

• Secondary commensal bacterial infections leading to mucopurulent discharge and productive cough

• May lead to pneumonia with high fever, inappetence, productive cough, and increased respiratory effort

Rabies Virus

• Variable incubation period, prodromal phase: nervousness, anxiety, paresthesia

• Progress to forebrain signs (“furious” form of rabies): irritability, restlessness, pica, photophobia, increased saliva production with decreasing ability to swallow, hyperesthesia progressing to incoordination, seizures, and death

• May also progress to “dumb” form: paralysis, lower motor disease, leading to coma, respiratory paralysis, and death

Pseudorabies

• Suspected to be result from ingestion of infected raw pork

• Neurologic dysfunction: ataxia, abnormal papillary light response, restlessness, trismus, cervical rigidity, ptyalism, tachypnea, excoriation from pruritus of head and neck; vomiting, diarrhea; most dogs die within 48 hours

Parainfluenza and Adenovirus Type 2

• Hacking cough with gagging, easily elicited with tracheal palpation; cough may be paroxysmal, usually subsides within 7–10 days, and may lead to secondary bacterial or mycoplasmal infection

Canine Herpesvirus

• Abortion, stillbirths; puppies born live progress to crying, hypothermia, soft stools, petechiae, cessation of nursing, and death

• Older puppies develop mild respiratory signs that may emerge later as neurologic disease (ataxia, blindness, central vestibular disease).

• Adult dogs: usually asymptomatic, rhinitis, pharyngitis, vaginal or preputial hyperemia, hyperplasia of vaginal mucosal lymphoid follicles, submucosal hemorrhage

Canine Oral Papillomavirus

• Oral papilloma (warts), may be quite extensive, spontaneously regress

West Nile Virus

• Clinical disease is uncommon.

Bornavirus

• Seropositivity in the absence of clinical signs appears possible.

• Tremors, salivation, mydriasis, circling

Canine Distemper Virus Infection, Clinical Findings

General Signs

• Fever

• Lethargy

• Depression

• Anorexia

• Dehydration

Respiratory Tract

• Mucoid to mucopurulent discharge

• Bronchopneumonia

  • •
    Coughing
  • •
    Crackles on auscultation
  • •
    Increased bronchovesicular sounds
  • •
    Dyspnea

• Sneezing

Gastrointestinal Tract

• Vomiting

• Small bowel diarrhea

Ocular Disease

• Mucopurulent ocular discharge

• Chorioretinitis, medallion lesions, optic neuritis, retinal detachment

• Keratoconjunctivitis sicca

• Anterior uveitis

Neurologic Disease

• Spinal cord lesion: paresis and ataxia

• Central vestibular disease: head tilt, nystagmus, other cranial nerve and conscious proprioception deficits

• Cerebellar disease: ataxia, head bobbing, hypermetria

• Cerebral disease: seizures, blindness

• Chorea myoclonus: rhythmic jerking of single muscles or muscle groups

Miscellaneous

• Tonsillar enlargement

• Pustular dermatosis

• Hyperkeratosis of nose and footpads

• Enamel hypoplasia

In Utero Infection

• Stillbirth

• Abortion

• “Fading puppy” syndrome in neonatal period

• Central nervous system signs at birth

Viruses, Feline

American Association of Feline Practitioners Guidelines for Retroviral Testing in Cats

• •Sick cats should be tested even if they have tested negative before.
• •Cats and kittens should be tested when they are first acquired.
• •Even cats not expected to live with other cats should be tested. This provides a health assessment of the individual, other cats may join the household, indoor cats may escape and expose other cats.
• •Tests should be performed at adoption and negative cats should be retested a minimum of 60 days later.
• • Cats with known recent exposure to a retrovirus-infected cat or a cat with unknown status, particularly via a bite wound, should be tested regardless of previous test results. Testing should be done immediately and, if negative, should be repeated after a minimum of 30 days for FeLV and after a minimum of 60 days for FIV (when the type of potential viral exposure is unknown, retesting for both viruses after 60 days is most practical).
• •Cats living in households with other cats infected with FIV or FeLV should be tested annually.
• •High-risk cats (cats in cat-dense neighborhoods or cats that fight and get cat-bite wounds and abscesses) should be tested regularly.
• •Cats should be tested before initial vaccination against FeLV or FIV.
• •Cats used for blood or tissue donation should have negative screening tests for FeLV and FIV and should be negative for real-time PCR tests.
• •Intermittent retesting is not necessary for cats with confirmed negative infection status unless there is opportunity for exposure to infected cats or if they become ill.
• •Each cat should be individually tested. Testing of one cat as a proxy for another or pooling samples from multiple cats for testing is inappropriate.

Clinical Signs of Rabies Virus Infection in Cats

• •Initially signs are nonspecific: lethargy, inappetence, vomiting, diarrhea
• •Rapid and continual deterioration of clinical conditions, no waxing and waning
• •Behavioral changes: more reclusive or attention-seeking, may unpredictably attack animate, inanimate, or unseen objects
• •Irrevocable progression to classic signs, ptyalism with decreased ability to swallow leads to contamination of oral cavity, chin, and forelegs with potentially infectious saliva. Cranial nerve signs such as anisocoria, pupil dysfunction, facial or tongue paresis, and changes in phonation may occur.
• •Auditory, visual, or tactile stimulation may elicit profound aggression to self-mutilation.
• •Become profoundly moribund to comatose to death. 100% fatal

Feline Infectious Peritonitis (FIP, Feline Coronavirus Infection), Clinical Findings

Signalment and History

• Purebred cats from cattery

• Multicat households

• Younger than 5 years or older than 10 years of age

• Previous history of mild, self-limiting gastrointestinal or respiratory disease

• Anorexia, weight loss, depression

• Seizures, nystagmus, ataxia

• Acute, fulminant course in cats with effusive FIP

• Chronic, intermittent course in cats with noneffusive FIP

Physical Examination Findings

• Fever

• Weight loss

• Abdominal distension/fluid wave

• Abdominal mass (focal intestinal granuloma, lymphadenopathy)

• Icterus

• Muffled heart or lung sounds

• Dyspnea secondary to pleural effusion

• Hepatomegaly

• Chorioretinitis, iridocyclitis

• Splenomegaly

• Pale mucous membranes with or without petechiae

• Multifocal neurologic abnormalities

• Irregularly marginated kidneys

• Renomegaly

Clinicopathologic Abnormalities

• Complete blood count (CBC): nonregenerative anemia, neutrophilia with or without left shift, lymphopenia

• Serum chemistry: elevated alkaline phosphatase (ALP) and alanine aminotransferase (ALT), hyperbilirubinemia, hyperglobulinemia (polyclonal, rarely monoclonal gammopathy), azotemia (prerenal or renal)

• Urinalysis: proteinuria

• Nonseptic, pyogranulomatous exudate in peritoneal cavity, pleural space, and pericardium

• Positive coronavirus antibody titer (especially in noneffusive cases)

• Cerebrospinal fluid (CSF) tap: increased protein concentration, neutrophilic pleocytosis, coronavirus antibodies

• Histopathology: pyogranulomatous inflammation in perivascular locations of tissues

• Positive for coronavirus on immunofluorescence or reverse-transcriptase polymerase chain reaction (RT-PCR) testing of abdominal or pleural effusions (although these tests do not differentiate between FIP-causing viruses and “harmless” feline enteric coronavirus)

Feline Immunodeficiency Virus (FIV) Infection, Clinical Findings

Primary Phase of Infection

• Low-grade fever

• Lymphadenopathy

• Neutropenia

Latent Phase

• No clinical signs for months to years

Immunodeficiency Phase

Primary Viral Effects

• Weight loss

• Nonregenerative anemia, neutropenia, thrombocytopenia

• Small bowel diarrhea

• Glomerulonephritis

• Myeloproliferative disorders

• Lymphoma

• Renal failure

• Anterior uveitis, pars planitis

• Behavioral abnormalities

Opportunistic Infectious Agents

• Cutaneous: atypical mycobacteriosis, demodicosis, Notoedres and Otodectes infestation, dermatophytosis, cryptococcosis, cowpox

• Gastrointestinal: cryptosporidiosis, coccidiosis, giardiasis, salmonellosis, campylobacteriosis, others

• Renal: bacterial infections, FIP, feline leukemia virus (FeLV)

• Urinary tract: bacterial infections

• Neoplasia: FeLV

• Hematologic: Mycoplasma haemofelis, FeLV, bartonellosis

• Neurologic: toxoplasmosis, cryptococcosis, FIP, FeLV

• Ophthalmologic: toxoplasmosis, FIP, cryptococcosis, herpesvirus, bartonellosis

• Pneumonia/pneumonitis: bacterial, toxoplasmosis, cryptococcosis

• Pyothorax: bacterial

• Stomatitis: calicivirus, bacterial, candidiasis, bartonellosis

• Upper respiratory: herpesvirus, calicivirus, bacterial, cryptococcosis

Feline Leukemia Virus (FeLV), Clinical Findings

Acute Phase

• Fever

• Malaise

• Diarrhea

• Leukopenia

General Signs

• Anorexia

• Weight loss

• Depression

• Many FeLV positive cats are asymptomatic at diagnosis

Neoplastic

• Lymphoma: mediastinal, multicentric, alimentary, renal

• Leukemia: lymphocytic, myelogenous, erythroid, megakaryocytic

• Myeloproliferative disorders

• Fibrosarcoma

Icterus

• Prehepatic: immune-mediated red blood cell (RBC) destruction induced by FeLV or secondary infection with Mycoplasma haemofelis

• Hepatic: hepatic lymphoma, focal liver necrosis, hepatic lipidosis

• Posthepatic: alimentary lymphoma

Bone marrow

• Pure red cell aplasia

• Regenerative anemia (less common and often associated with coinfection with Mycoplasma haemofelis)

• Myeloproliferative disease (anemia, leukopenia, thrombocytopenia)

Stomatitis

• Bacterial infection

• Calicivirus infection

Rhinitis/Pneumonia

• Bacteria

• Herpesvirus and calicivirus

Renal

• Glomerulonephritis

• Renal failure

• Urinary incontinence: sphincter incompetence or detrusor hyperactivity

Ocular Lymphoma

• Aqueous flare, mass lesions, keratitic precipitates, lens luxations, glaucoma, anterior uveitis

Neurologic Polyneuropathy or lymphoma

• Anisocoria, ataxia, weakness, tetraparesis, paraparesis, behavioral changes, urinary incontinence

• Secondary infection with FIP, Toxoplasma gondii, Cryptococcus neoformans

In Utero Infection

• Abortion, stillbirth, infertility, kitten mortality complex (“fading kitten” syndrome)

Lameness

• Neutrophilic polyarthritis secondary to immune complex deposition

• Multiple cartilaginous exostoses

Feline Leukemia Virus, Possible Outcomes Following Exposure

Progressive Infection

• Viral replication in lymphoid tissue and bone marrow, spread to mucosal and glandular tissues, leading to shedding of virus. Most cats become persistently infected and frequently die of an FeLV-associated disease within a few years.

Regressive Infection

• Effective immune response limits viral replication. FeLV antigen detectable in peripheral blood within 2–3 weeks after exposure but disappears 2–8 weeks later. May not ever develop antigenemia. Clinical relevance of regressive infection is not clear. May have persistent integration of FeLV DNA in their genome but are unlikely to develop FeLV-associated diseases. Do not shed virus.

Abortive Exposure

• Seen infrequently following experimental FeLV inoculation characterized by negative results for culturable virus, antigen, viral RNA, and proviral DNA

Focal Infections

• Rare events in which cats have FeLV infection restricted to certain tissues such as spleen, lymph nodes, small intestine, or mammary glands.

Other Feline Viral Diseases

Upper Respiratory Tract Viruses

• Herpesvirus type 1: ocular and nasal disease

• Calicivirus: ocular, nasal, and oral disease; rarely joint disease

• Reovirus: Conjunctivitis, respiratory lesions, diarrhea experimentally, no evidence of importance in the field

Enteric Viruses

• Feline parvovirus (panleukopenia virus): enteritis, panleukopenia, cerebellar hypoplasia, fetal death

• Feline coronavirus: mild enteritis, FIP

• Rotavirus: rare cause of mild diarrhea

• Astrovirus: uncommon cause of persistent watery diarrhea

• Torovirus: may be associated with protruding nictitating membrane and diarrhea syndrome

Miscellaneous

• Cowpox virus: mainly see skin lesions; sporadic disease in cats Hantavirus: zoonotic disease of wild rodents; clinical significance in cats not known

• Rabies virus

• Pseudorabies virus: cats are a rare host, severe behavioral changes, pruritus, paralysis, coma, death

• Feline herpesvirus type 2: possible association with feline idiopathic lower urinary tract disease

SECTION VIII. Joint and Bone Disorders

• Arthritis

• Bone Disorders

Arthritis

Differential Diagnosis: Infectious Arthritis

Septic Arthritis

Bacterial Suppurative Arthritis

• Penetrating wounds

  • •
    Animal bites
• Iatrogenic

  • •
    Infection during surgery, arthrocentesis

• Trauma (e.g., hit by car)

• Hematogenous

  • •
    Endocarditis
  • •
    Omphalophlebitis
  • •
    Pyoderma
  • •
    Other foci of infection

Lyme Arthritis

• Borrelia burgdorferi

• Transmitted by Ixodes ticks

Bacterial l-Form Arthritis

• Cell wall–deficient bacteria

• Causes suppurative arthritis and subcutaneous abscesses in cats

Mycoplasma Arthritis

• Debilitated and immunosuppressed animals

• M. gatae, M. felis in cats

Fungal Arthritis (Rare)

• Coccidioides immitis

• Blastomyces dermatitidis

• Cryptococcusneoformans

• Sporothrix schenckii

• Aspergillus terreus

Rickettsial Arthritis

• Rocky Mountain spotted fever (Rickettsia rickettsii)

• Ehrlichia canis

• Anaplasma phagocytophilium

Protozoal Arthritis

• Leishmaniasis (Leishmania spp.)

• Toxoplasmosis (rare)

• Neosporosis (Neospora caninum): polyarthritis, polymyositis, neurologic disease

• Hepatozoonosis: polyarthritis and polymyositis in dog and cat

• Babesiosis (rare, more often causes severe anemia)

Viral Arthritis

• Calicivirus infection in cats

Differential Diagnosis of Noninfectious Arthritis

Nonerosive

• Immune-mediated polyarthritis

• Systemic lupus erythematosus

• Reactive polyarthritis (bacterial, fungal, parasitic, neoplastic, enterohepatic, drug reaction, vaccine induced)

• Breed-associated syndromes

  • Polyarthritis (Akita, Newfoundland, Weimaraner)
  • Polyarthritis/meningitis (Akita, Beagle, Bernese Mountain Dog, Boxer, German Shorthair Pointer)
  • Polyarthritis/polymyositis (spaniels)
  • Familial Shar-Pei fever

• Lymphoplasmacytic synovitis

Erosive

• Rheumatoid-like arthritis

• Erosive polyarthritis of Greyhounds

• Feline chronic progressive polyarthritis

Bone Disorders

Differential Diagnosis: Congenital, Developmental, Genetic

Congenital

• Hemimelia, phocomelia, amelia: absence of portions or entire limb (amelia)

• Syndactyly: fusion of two or more digits; rarely clinically significant

• Polydactyly: extra digits

• Ectrodactyly: third metacarpal and digit missing forming a cleft (split or “lobster” claw)

• Segmented hemiatrophy: limb hypoplasia

Developmental and Genetic

• Osteopetrosis: rare; diaphysis remains filled with bone, marrow does not form, fragile bones

• Osteogenesis imperfecta: heritable diseases—fragile bones

• Mucopolysaccharidosis: rare lysosomal storage disease—Siamese cats—causes dwarfism, facial dysmorphism

• Dwarfism

  • •
    Osteochondrodysplasias
  • •
    Pituitary dwarfism
  • •
    Congenital hypothyroidism

• Retained cartilage cores

• Craniomandibular osteopathy (West Highland White Terrier, Scottish Terrier, Cairn Terrier, Boston Terrier, other terriers)

• Multiple cartilaginous exostoses

Differential Diagnosis: Metabolic, Nutritional, Endocrine, Idiopathic

Metabolic

• Nutritional secondary hyperparathyroidism

• Lead poisoning

Nutritional

• Rickets (hypovitaminosis D)

• Renal osteodystrophy

• Hypervitaminosis A: causes osteopathy

• Hypovitaminosis A: deformed bones secondary to impedance of bone remodeling

• Hypervitaminosis D: skeletal demineralization

• Zinc-responsive chondrodysplasia

• Copper deficiency

• Overnutrition of growing dogs

Endocrine

• Primary hyperparathyroidism

• Humoral hypercalcemia of malignancy

• Hyperadrenocorticism

• Hypogonadism: delay in physis closure after early gonadectomy

• Hepatic osteodystrophy

• Anticonvulsant osteodystrophy

Idiopathic

• Enostosis (panosteitis)

• Metaphyseal osteopathy (hypertrophic osteodystrophy)

• Avascular necrosis of femoral head (Legg-Calvé-Perthes disease)

• Secondary hypertrophic osteopathy (usually in response to thoracic neoplasia)

• Medullary bone infarction

• Bone cyst

• Aneurysmal bone cyst

• Subchondral bone cyst

• Fibrous dysplasia

• Central giant cell granuloma

SECTION IX. Liver and Exocrine Pancreatic Disorders

• Cholangitis and Cholangiohepatitis, Feline

• Exocrine Pancreatic Disease

• Gallbladder and Extrahepatic Biliary Disease

• Hepatic Encephalopathy

• Hepatic Lipidosis, Feline

• Hepatobiliary Disease

• Hepatomegaly and Microhepatica

• Hyperlipidemia

• Pancreatitis

• Portosystemic Shunt, Congenital

• Vacuolar Hepatopathy, Canine

Cholangitis and Cholangiohepatitis, Feline

Comparative Clinical Findings

Suppurative (Neutrophilic) Cholangitis and Cholangiohepatitis

• Middle-aged to older cats

• Often depressed and ill

• Anorexia (usually)

• Jaundice

• Neutrophilia

• Increased alanine aminotransferase (ALT)

• Increased alkaline phosphatase (ALP)

• Increased bilirubin (±)

• Increased serum and urine bile acids (±)

• Hyperechoic liver and bile stasis

• Primarily neutrophilic infiltrate

• Lesions surround bile ducts

• May be associated with pancreatitis and/or inflammatory bowel disease

• Respond to antibiotics and supportive nonspecific treatments

Lymphocytic Cholangitis

• Younger cats

• Persians

• Bright and alert

• Polyphagia (±)

• Ascites (±)

• Icterus (±)

• Lymphadenopathy (±)

• Hepatomegaly (±)

• Neutrophilia (±)

• Lymphopenia (±)

• Bile acids (±)

• Increased ALT

• Increased ALP

• Bilirubinemia/bilirubinuria (±)

• Hyperglobulinemia

• Hyperechoic liver (±)

• Primarily lymphocytic infiltrate

• Lesions found in portal areas

• Variable fibrosis

• Pancreatitis (may be present)

• Positive response to immunosuppressive corticosteroids

Exocrine Pancreatic Disease

Differential Diagnosis

• Pancreatitis

  • •
    Acute
  • •
    Chronic

• Exocrine pancreatic insufficiency

• Pancreatic pseudocyst

• Pancreatic abscess

• Exocrine pancreatic neoplasia

  • •
    Pancreatic adenoma
  • •
    Pancreatic adenocarcinoma
  • •
    Pancreatic sarcoma (spindle cell sarcoma, lymphosarcoma) rare

• Nodular hyperplasia

• Pancreatic parasites (cats)

  • •
    Eurytrema procyonis (pancreatic fluke)
  • •
    Amphimerus pseudofelineus (hepatic fluke)
• Pancreatic bladder

  • •
    Abnormal extension of pancreatic duct (rare finding in cat)

Clinical Findings of Exocrine Pancreatic Insufficiency

• Most often seen in young to middle-aged dogs; German Shepherds are predisposed

• Chronic weight loss

• Ravenous appetite

• Coprophagia

• Pica

• Change in fecal character

  • •
    Voluminous
  • •
    Soft
  • •
    Watery
  • •
    May be normal

• Poor haircoat quality

• Borborygmus, flatulence

• Coagulation disorder (caused by malabsorption of vitamin K, rare)

Gallbladder and Extrahepatic Biliary Disease

Differential Diagnosis

Obstructive Disease

• Extrahepatic biliary obstruction

  • •
    Pancreatitis (most common etiology in dog)
  • •
    Biliary neoplasia
  • •
    Cholangitis
  • •
    Pancreatic neoplasia

• Cholelithiasis/choledocholithiasis

• Gallbladder mucocele

Nonobstructive Disease

• Cholecystitis

  • •
    Bacterial cholecystitis (ascending infection—Escherichia coli most common)
  • •
    Necrotizing cholecystitis
  • •
    Emphysematous cholecystitis (E. coli, Clostridium perfringens)

• Cholelithiasis/choledocholithiasis (does not always cause obstruction)

• Parasites (mainly seen in cats) Tropical climates (seen in cats that eat lizards or toads)

  • •
    Platynosomum fastosum (a fluke)
  • •
    Amphimerus pseudofelineus
  • •
    Metorchis conjunctus
  • •
    Eurytrema procyonis

• Gallbladder infarct

Neoplasia

• Biliary cystadenoma

• Bile duct carcinoma

Caroli Disease

• Dilatation of intrahepatic and extrahepatic bile ducts

Gallbladder Rupture

• Necrotizing cholecystitis

• Obstruction

• Iatrogenic

• Blunt abdominal trauma

• Gallbladder torsion

Clinical Findings of Gallbladder and Biliary Disease

Clinical Signs

• Vomiting

• Icterus

• Anorexia

• Fever

• Abdominal pain

• Depression

• Weight loss

• Ascites/bile peritonitis

Clinicopathologic Findings

• Hyperbilirubinemia

• Elevated alkaline phosphatase (ALP) levels

• Elevated gamma glutamyltransferase (GGT) levels

• Elevated serum bile acids

• Elevated alanine aminotransferase (ALT) levels

• Hypercholesterolemia

• Stress leukogram

• Nonregenerative anemia

Radiographic Findings

• Hepatomegaly

• Mass effect in area of gallbladder

• Gas shadow in area of gallbladder

• Choleliths radiopaque if they contain calcium (50% may not be seen on radiographs)

Ultrasonographic Signs

• Dilated and tortuous bile ducts

• Gallbladder distension

• Thickened gallbladder wall

• Cholelith visible

• Pancreatic mass identified

• Stellate appearance to contents of gallbladder (characteristic of a gallbladder mucocele)

Hepatic Encephalopathy

Clinical Findings

General Systemic Clinical Signs

• Anorexia

• Depression

• Weight loss

• Lethargy

• Nausea

• Fever

• Ptyalism

• Intermittent vomiting

• Diarrhea

Central Nervous System Clinical Signs

• Tremors

• Ataxia

• Personality change (often toward aggression)

• Dementia

• Head pressing

• Pacing

• Circling

• Hysteria

• Cortical blindness

• Seizures

• Coma

Hepatic Lipidosis, Feline

Clinical Findings

Historical Findings

• Obesity

• Recent anorexia and rapid weight loss

  • •
    Concurrent disease that causes anorexia (pancreatitis, diabetes mellitus, inflammatory hepatobiliary disease, inflammatory bowel disease, feline infectious peritonitis, chronic renal failure, neoplasia, cardiomyopathy, neurologic disease, etc.)
  • •
    Stressful event
  • •
    Abrupt diet change

• Typically indoor cats

Physical Findings

• Jaundice

• Vomiting

• Dehydration

• Hepatic encephalopathy

  • •
    Depression
  • •
    Ptyalism

• Hepatomegaly

Clinicopathologic Findings

• Typical findings of cholestasis

  • •
    Moderate increase in alanine aminotransferase (ALT)
  • •
    Marked increase in alkaline phosphatase (ALP)
  • •
    Mild increase in gamma glutamyltransferase (GGT); disproportionately low compared with other feline cholestatic hepatopathies
  • •
    Elevated serum bile acids typical

• Coagulation test abnormalities (especially in conjunction with acute pancreatitis)

Cytology (Ultrasound-Guided Needle Aspirates) and Histopathology

• Reveal clear vacuolation of most hepatocytes, nonzonal in distribution; typically with absence of inflammatory cells

Hepatobiliary Disease

Clinical and Physical Findings

General Clinical Features

• Depression

• Anorexia

• Lethargy

• Weight loss

• Poor haircoat, insufficient grooming

• Nausea, vomiting

• Diarrhea

• Dehydration

• Small body stature

• Polydipsia, polyuria

Signs Specific but Not Pathognomonic for Hepatic Disease

• Icterus

• Bilirubinuria

• Acholic feces

• Organomegaly

• Ascites

• Hepatic encephalopathy

  • •
    Behavioral changes (aggression, dementia, hysteria)
  • •
    Circling
  • •
    Ataxia
  • •
    Staggering
  • •
    Pacing
  • •
    Head pressing
  • •
    Cortical blindness
  • •
    Ptyalism
  • •
    Tremors/seizures
  • •
    Coma

• Coagulopathies

• Polydipsia/polyuria

Causes of Elevated Serum Hepatobiliary Enzymes

Primary Hepatic Disease

 

Drug Induction

• Corticosteroids (dogs)

• Anticonvulsants (phenobarbital, phenytoin, primidone)

Endocrinopathies

• Hyperadrenocorticism (dogs)

• Hypothyroidism (dogs)

• Hyperthyroidism (cats)

• Diabetes mellitus

Bone Disorders

• Growing animals

• Osteosarcoma

• Osteomyelitis

Neoplasia

• Adenocarcinomas (pancreatic, intestinal, adrenocortical, mammary)

• Sarcomas (hemangiosarcoma, leiomyosarcoma)

• Hepatic metastasis

Muscle Injury

• Acute muscle necrosis/trauma

• Myopathies

• Malignant hyperthermia

Hypoxia/Hypotension

• Septic shock

• Surgery

• Congestive heart failure

• Hypoadrenocorticism

• Circulatory shock

• Severe acute blood loss

• Hypotensive crisis

• Status epilepticus

Gastrointestinal Disease

• Pancreatitis

• Inflammatory bowel disease

Miscellaneous Causes

• Systemic infections

• Pregnancy (cats—increased placental alkaline phosphatase)

• Colostrum-fed neonates (dogs)

• Breed related (Scottish terrier)

Differential Diagnosis, Dogs

Inflammation

• Chronic hepatitis complex

  • •
    Copper accumulation—Bedlington Terrier, Airedale Terrier, Bull Terrier, Bulldog, Cocker Spaniel, Collie, Dachshund, Dalmatian, Doberman Pinscher, German Shepherd, Golden Retriever, Keeshond, Kerry Blue Terrier, Labrador Retriever, Norwich Terrier, Old English Sheepdog, Pekingese, Poodle, Samoyed, Schnauzer, Skye Terrier, West Highland White Terrier, Wire Fox Terrier
  • •
    Drug induced: trimethoprim-sulfa, phenobarbital, diethylcarbamazine, oxibendazole, many others
  • •
    Familial hepatitis—Doberman Pinscher, West Highland White Terrier, Dalmatian, Skye Terrier, Cocker Spaniel

• Fibrosis and cirrhosis (results from any severe or chronic hepatic insult)

• Infectious agents: leptospirosis, canine adenovirus type 1 infection, bacterial hepatitis, histoplasmosis, Rocky Mountain spotted fever, ehrlichiosis, babesiosis, leishmaniasis

• Cholangiohepatitis

• Granulomatous hepatitis

  • •
    Rhodococcus, Borrelia, Bartonella, Histoplasma, Coccidioidomyces, Hepatozoon, Heterobilharzia Nocardia, Mycobacterium spp.

• Acidophil cell hepatitis

• Lobular dissecting hepatitis

• Hepatic abscess

Acute Toxic or Drug-Induced Hepatopathy

 

Vacuolar Hepatopathy

 

Metabolic Liver Disease

• Amyloidosis

• Hyperlipidemia

• Lysosomal storage disease

Vascular Hepatic Disease

• Congenital portosystemic venous anomaly

• Intrahepatic portal vein hypoplasia

• Intrahepatic arteriovenous fistula

Biliary Tract Disease

 

Neoplasia

• Primary: hepatocellular carcinoma, hepatocellular adenoma, hepatic hemangiosarcoma, biliary carcinoma

• Other hepatic tumors: leiomyosarcoma, liposarcoma, myxosarcoma, fibrosarcoma, biliary adenoma, hepatic carcinoid

• Hemolymphatic: lymphosarcoma, mast cell tumor, plasma cell tumor

• Metastatic neoplasia

Hepatic or Biliary Cysts

 

Differential Diagnosis, Cats

Hepatic Lipidosis

 

Inflammatory Hepatobiliary Disease

• Cholangitis/cholangiohepatitis complex

  • •
    Suppurative (neutrophilic) cholangitis, cholangiohepatitis
  • •
    Lymphocytic cholangitis

• Chronic cholangiohepatitis (later stage of acute cholangiohepatitis)

• Sclerosing cholangitis

• Lymphocytic portal hepatitis

• Feline infectious peritonitis (FIP)

Toxic Hepatopathy

• Antimicrobials (trimethoprim-sulfa, tetracycline)

• Anticonvulsants (phenobarbital)

• Diazepam

• Methimazole

• Griseofulvin

• Ketoconazole

• Pine oils (cleaning agents)

• Amanita phalloides (death cap mushroom)

• Natural or herbal remedies

• Many others

Portosystemic Venous Anomaly

 

Lipoprotein Lipase Deficiency

 

Neoplasia

Primary Hepatic Neoplasia

• Biliary carcinoma

• Hepatocellular carcinoma

• Hepatic hemangiosarcoma

• Bilary cystadenoma

• Myelolipoma

• Hepatic carcinoid

Hemolymphatic Neoplasia

• Lymphosarcoma

• Mast cell tumor

• Plasma cell tumor

Metastatic Neoplasia

 

Hepatomegaly and Microhepatica

Differential Diagnosis

Generalized Hepatomegaly

• Acute toxic hepatopathy

• Infiltrative hepatic disease

  • •
    Neoplasia: primary or metastatic
  • •
    Chronic hepatitis complex (dog)
  • •
    Cholangiohepatitis (cat)
  • •
    Extramedullary hematopoiesis
  • •
    Mononuclear-phagocytic cell hyperplasia
  • •
    Amyloidosis (rare)
• Passive congestion

  • •
    Right-sided heart failure
  • •
    Pericardial disease (dog)
  • •
    Caval syndrome (dog)
  • •
    Caudal vena cava obstruction (dog)
  • •
    Budd-Chiari syndrome (rare)
• Hepatocellular hypertrophy

  • •
    Hepatic lipidosis
  • •
    Steroid hepatopathy
  • •
    Anticonvulsant drug therapy

• Acute extrahepatic bile duct obstruction

Focal Hepatomegaly

• Neoplasia: primary or metastatic

• Nodular hyperplasia

• Chronic hepatic disease with fibrosis and nodular regeneration

• Hepatic abscess

• Hepatic cyst

Microhepatica

• Decreased hepatic mass

  • •
    Chronic hepatic disease with progressive loss of hepatocytes
• Decreased portal blood flow with hepatocellular atrophy

  • •
    Congenital portosystemic shunt
  • •
    Intrahepatic portal vein hypoplasia
  • •
    Chronic portal vein thrombosis
• Hypovolemia

  • •
    Hypoadrenocorticism
  • •
    Shock

Hyperlipidemia

Differential Diagnosis

Postprandial Hyperlipidemia

 

Primary

• Idiopathic hyperlipoproteinemia of Miniature Schnauzers

• Feline familial hyperchylomicronemia

• Idiopathic hypercholesterolemia (rare—Doberman Pinscher, Rottweiler)

• Idiopathic hypercholesterolemia

Secondary

• Endocrine

  • •
    Hypothyroidism
  • •
    Diabetes mellitus
  • •
    Hyperadrenocorticism

• Pancreatitis

• Nephrotic syndrome

• Hepatic insufficiency

• Cholestasis

• Drug induced

  • •
    Glucocorticoids
  • •
    Megesterol acetate

Clinical Findings

Severe Hyperlipidemia

• Intermittent gastrointestinal signs

  • •
    Vomiting
  • •
    Diarrhea
  • •
    Abdominal discomfort

• Seizures

• Pancreatitis

• Lipemia retinalis

• Cutaneous xanthomas

• Peripheral nerve paralysis

• Behavioral changes

Severe Hypercholesterolemia

• Arcus lipoides corneae

• Lipemia retinalis

• Atherosclerosis

Pancreatitis

Clinical Findings of Acute Pancreatitis

Dogs

Mild Acute Pancreatitis

• Depression

• Anorexia

• Nausea, vomiting, diarrhea

• Ptyalism

• Mild right cranial abdominal pain

• Fever, dehydration, weakness

Moderate to Severe Acute Pancreatitis

• Depression

• Anorexia

• Vomiting

• Right cranial abdominal pain

• Hematemesis, hematochezia, melena

• Jaundice

• Respiratory distress

• Shock, fever, dehydration

• Hyperemic mucous membranes

• Tachycardia, tachypnea

• Abdominal effusion

• Mass effect in region of pancreas

• Petechiae, ecchymoses

• Cardiac arrhythmia

• Glossitis, glossal slough

• Extrahepatic biliary obstruction

Cats

• Signs tend to be more subclinical and nonspecific.

• May be associated with inflammatory bowel disease

• May be component of multisystemic disease such as toxoplasmosis

• Lethargy, anorexia, vomiting, dehydration, weight loss, jaundice, hypothermia

• May present as acute necrotizing or acute suppurative form

Predisposing Factors

Nutritional

• Obesity

• High-fat diet

• After ingestion of large, fatty meal

Hypertriglyceridemia

• Hyperlipoproteinemia (Idiopathic in Miniature Schnauzers)

• Endocrine (diabetes mellitus, hyperadrenocorticism, hypothyroidism)

Drugs

• Chemotherapeutic agents

  • •
    l-Asparaginase
  • •
    Azathioprine
  • •
    Others

• Organophosphates

• Asparaginase

• Thiazides

• Furosemide

• Estrogens

• Sulfa drugs

• Procainamide

• Potassium bromide

• Tetracyclines

Ischemia

• Hypovolemia

• Associated with disseminated intravascular coagulation (DIC)

• Vasoactive amine–induced vasoconstriction

• Surgery

• Gastric dilatation/volvulus

• Severe immune-mediated hemolytic anemia

Duodenal Reflex

• Increased intraluminal pressure during severe vomiting

Other

• Cholangitis

• Infection (toxoplasmosis, feline infectious peritonitis)

• Abdominal trauma

• Hypercalcemia

• Trauma

Clinicopathologic Findings in Dogs and Cats with Acute Pancreatitis

• •BUN/creatinine—increased in 50 to 65% of dogs and in 33% (Cr) and 57% (BUN) in cats. Usually prerenal due to dehydration and hypotension. May be secondary to intrinsic renal failure (sepsis and immune-complex)
• •Potassium—decreased in 20% of cases in dogs and 56% in cats. Increased loss in vomiting and due to renal loss with fluid therapy plus reduced intake and aldosterone release caused by hypovolemia
• •Sodium—can be increased, decreased or normal. Increase usually caused by dehydration, decrease caused by losses secondary to vomiting
• •Calcium—Commonly decreased in cats, rarely in dogs, rarely increased in both dogs and cats. Reduction is a poor prognostic indicator in cats but no prognostic significance in dogs. May be caused by saponification in peripancreatic fat and glucagon release stimulating calcitonin
• •Chloride—Very commonly decreased in dogs. Loss in gastrointestinal secretions in vomiting
• •Phosphate—Often increased in dogs, uncommonly increased or decreased in cats. Increase usually due to reduced renal excretion secondary to renal compromise. Decrease (in cats) due to treatment for diabetes mellitus
• •Glucose—increased in 40–88% of dogs and decreased in up to 40%. Increased in 64% of cats, rarely decreased. Increase due to decreased insulin and increased glucagon, cortisol, and catecholamines. Decrease caused by sepsis or anorexia
• •Albumin—Increased in 39–50% and decreased in 17% of dogs. Increased in 8–30% and decreased in 40% of cats. Increase due to dehydration. Decrease due to gut loss, malnutrition, concurrent hepatic disease, or renal loss
• •Hepatocellular enzymes (ALT, AST)—increased in 61% of dogs and 68% of cats. Hepatic necrosis and vacuolation due to sepsis, local effects of pancreatitis +/− concurrent hepatic disease in cats
• •Cholestatic enzymes (ALP and GGT)—Increased in 79% of dogs and 50% of cats. Biliary obstruction due to acute or chronic pancreatitis +/− concurrent cholangitis +/− lipidosis in cats; steroid-induced ALP in dogs
• •Bilirubin—Increased in 53% of dogs and 64% of cats (same causes as GGT and ALP)
• • Cholesterol—Increased in 48–80% of dogs and 64% of cats. Can be due to cholestasis; unclear if cause or effect
• •Triglycerides—Commonly increased in dogs. Unclear if cause or effect
• •Neutrophils—Increased in 55–60% of dogs, increased in 30% and decreased in 15% of cats. Increased due to inflammatory response. Decreased in some cats due to consumption, may be a poor prognostic indicator
• •Hematocrit—Increased in about 20% and decreased in 20% of both dogs and cats. Increased due to dehydration and decreased due to anemia of chronic disease or gastric ulceration
• •Platelets—Commonly decreased in severe cases in dogs. Decreased due to circulating proteases +/− disseminated intravascular coagulation

Portosystemic Shunt, Congenital

Clinical Findings

Signalment

• Young animal, male or female, often purebred

History

• Neurologic signs (dementia, circling, central blindness, personality change, head pressing, wall hugging, seizures)

• Vomiting

• Diarrhea

• Ptyalism (especially cats)

• Worsening of signs after eating

• Improvement of signs with antimicrobial therapy

• Prolonged recovery from anesthesia

• Polydipsia/polyuria

• Recurrent urate urolithiasis in breeds other than Dalmatian and English Bulldog

Physical Examination

• Poor haircoat

• Small stature

• Cystic calculi

• Cryptorchidism

• Bilateral renomegaly

• Copper-colored irises in non-Asian cat breeds

• Other congenital anomalies

Clinicopathologic Findings

• Microcytosis

• Hypoalbuminemia

• Mild increases in hepatic enzymes

• Hypocholesterolemia

• Low BUN

• Normal to high resting bile acids/elevated postprandial bile acids

• Hyposthenuria

• Urate crystalluria and urolithiasis

Vacuolar Hepatopathy, Canine

Differential Diagnosis

• Hyperadrenocorticism

  • •
    Pituitary dependent
  • •
    Adrenal dependent
  • •
    Iatrogenic (glucocorticoid therapy)
• Pancreatitis

  • •
    Chronic

• Severe hypothyroidism

• Chronic stress

  • •
    Illness of more than 4 months

• Chronic infection or inflammation (e.g., pyelonephritis, chronic dermatitis)

• Severe dental disease

  • •
    Oral infection
• Disorders affecting lipid metabolism

  • •
    Diabetes mellitus
  • •
    Idiopathic hyperlipidemia
• Neoplasia

  • •
    Lymphoma

• Congestive heart failure

• Abnormal sex hormone production

• Inflammatory bowel disease

  • •
    Chronic, lymphoplasmacytic, eosinophilic

• Hepatocutaneous syndrome

SECTION X. Neoplasia

• Chemotherapeutic Agent Toxicity

• Corticosteroid Therapy

• Histiocytic Disease

• Humoral Hypercalcemia

• Lymphoma

• Paraneoplastic Syndromes

• Sarcomas

• Thyroid Neoplasms

• Tumors

Chemotherapeutic Agent Toxicity

• Most severely affects tissues with a growth fraction that approaches that of tumor cells

Clinical Findings

Myelosuppression

• Neutropenia: short-lived cells; nadir is 5–10 days postchemotherapy

• Thrombocytopenia: nadir is 7–14 days postchemotherapy

• Anemia: erythrocytes live longer; rarely clinically significant

Gastrointestinal Toxicity

• Nausea, vomiting

• Diarrhea

• Inappetence

• Anorexia

Cardiotoxicity

• Doxorubicin therapy

• Breeds susceptible to dilated cardiomyopathy (e.g., Doberman) most sensitive

• Most likely after cumulative dose of 180 mg/m²

Nephrotoxicity

• Cisplatin, streptozotocin

• Limit use of cisplatin in cases of preexisting renal disease.

Hepatopathy

• Irreversible hepatic toxicity may result if lomustine (CCNU) given in face of elevated ALT

Urothelial Toxicity

• Sterile hemorrhagic cystitis

• Cyclophosphamide, ifosfamide

Extravasation

• Doxorubicin: severe local reaction leading to slough

• Vincristine: usually minor tissue damage

Hypersensitivity

• Doxorubicin: caused by histamine release from mast cells; prevented by slow administration

• l-Asparaginase: less likely if given subcutaneously rather than intravenously

• Etoposide, paclitaxel: caused by carrier solutions for these agents

Alopecia

• Less of a problem in dogs and cats than in people

• Worse in breeds that have hair (e.g., Poodles, Terriers, Old English Sheepdogs) than in dogs with fur

• Loss of “feathers” (e.g., Golden Retrievers)

• Loss of whiskers in cats

Neurologic Toxicity

• Fatal neurotoxicity in cats with topical or systemic administration of 5-fluorouracil

Respiratory Toxicity

• Fatal, acute pulmonary edema in cats with cisplatin therapy

Corticosteroid Therapy

Adverse Effects Associated with Glucocorticoid Administration

• Polyuria/polydipsia

• Polyphagia

• Increased alkaline phosphatase (ALP) levels

• Increased gamma glutamyltransferase (GGT) levels

• Panting

• Insomnia, agitation, behavioral changes

• Immunosuppression

  • •
    Secondary infection
  • •
    Recrudescence of latent infection
  • •
    Worsening of existing infection
  • •
    Demodicosis

• Vacuolar hepatopathy

• Iatrogenic hyperadrenocorticism

• Adrenocorticoid deficiency with rapid withdrawal after sustained use

• Alopecia

• Calcinosis cutis

• Comedones

• Skin thinning

• Proteinuria

• Muscle atrophy/muscle wasting

• Myotonia/myopathy

• Delayed wound healing

• Colonic perforation

• Gastrointestinal ulceration

• Insulin resistance

• Diabetes mellitus

• Hyperlipidemia

• Abortion

• Growth suppression

• Hypercoagulable state

• Ligament and tendon rupture

• Psychosis/behavior change

• Lowered seizure threshold

• Osteopenia

Histiocytic Disease

Classification, Dogs

May be difficult to differentiate from lymphoproliferative, granulomatous, or reactive inflammatory disease by histopathology alone

Cutaneous Histiocytoma

• Benign, usually solitary lesion

• Typically young dogs

• Often spontaneously regress

Langerhans Cell Histiocytoma

• Rare, rapidly metastatic, cutaneous infiltration by histiocytes, may be limited to multiple cutaneous sites or may affect lymph nodes and internal organs

Cutaneous Histiocytosis

• Single or multiple lesions

• May spontaneously regress

• May respond to immunosuppressive drugs

Systemic Histiocytosis

• Familial disease of Bernese Mountain Dogs, rarely other breeds

• Similar lesions to cutaneous histiocytosis but may also affect mucous membranes, lymphoid organs, lung, bone marrow, and other organ systems

• Progressive, requires immunosuppressive therapy

Histiocytic Sarcoma

• Bernese Mountain Dog, Rottweiler, Flat-Coated Retriever, Golden Retriever, rarely other breeds

• Histiocytic sarcoma usually begins as a localized lesion in spleen, lymph nodes, lung, bone marrow, skin and subcutis, brain, and periarticular tissue of appendicular joints.

  • •
    Rapidly disseminates to multiple organs

Malignant Histiocytosis

• Bernese Mountain Dog, Rottweiler, Flat-Coated Retriever, Golden Retriever, rarely other breeds

• Multisystemic, rapidly progressive disease of multiple organs

Classification, Cats

Feline Progressive Histiocytosis

• Rare, usually see multiple skin nodules, papules, plaques

• Head, lower extremities, trunk

• Poor long-term prognosis

Feline Histiocytic Sarcoma

• Poorly demarcated tumors of subcutis or spleen

• Poor prognosis

Humoral Hypercalcemia

Differential Diagnosis

Hematologic Cancers

• •Lymphosarcoma
• •Lymphocytic leukemia
• •Myeloproliferative disease
• •Myeloma

Solid Tumors with Bone Metastasis

• •Mammary adenocarcinoma
• •Nasal adenocarcinoma
• •Epithelial-derived tumors
• •Pancreatic adenocarcinoma
• •Lung carcinoma

Solid Tumors without Bone Metastasis

• •Apocrine gland adenocarcinoma of the anal sac
• •Interstitial cell tumor
• •Squamous cell carcinoma
• •Thyroid adenocarcinoma
• • Lung carcinoma
• •Pancreatic adenocarcinoma
• •Fibrosarcoma

Lymphoma

Common Differential Diagnoses

Generalized Lymphadenopathy

• Disseminated infections

  • •
    Bacterial, fungal, rickettsial, parasitic, viral
• Immune-mediated disease

  • •
    Systemic lupus erythematosus (SLE), polyarthritis vasculitis, dermatopathy
• Other hematopoietic tumors

  • •
    Leukemia, multiple myeloma, malignant or systemic histiocytosis

• Neoplasia metastatic to lymph nodes

• Benign reactive hyperplastic syndromes in cats

Alimentary Disease

• Inflammatory bowel diseases

  • •
    Lymphocytic/plasmacytic, eosinophilic enteritis

• Nonlymphoid intestinal neoplasia

• Granulomatous enteritis

• Granulated round cell tumors in cats

• Gastrointestinal mast cell neoplasia in cats

Cutaneous Disease

• Infectious dermatitis (deep pyoderma, fungal dermatitis)

• Immune-mediated dermatitis (e.g., pemphigus foliaceus)

• Other cutaneous neoplasms

Mediastinal Disease

• Thymoma

• Chemodectoma (heart base tumor)

• Ectopic thyroid neoplasia

• Pulmonary lymphomatoid granulomatosis

• Granulomatous disease (e.g., hilar lymphadenopathy with blastomycosis)

Paraneoplastic Syndromes

Classification

General

• Cancer anorexia, cachexia

• Fever

Hematologic

• Anemia

  • •
    Anemia of chronic disease
  • •
    Immune-mediated hemolytic anemia
  • •
    Bone marrow infiltration
  • •
    Blood loss anemia
  • •
    Hyperestrogenism
  • •
    Microangiopathic hemolytic anemia
• Polycythemia (rare)

  • •
    Associated with renal neoplasia, nasal fibrosarcoma, lymphoma, bronchial carcinoma, cecal leiomyosarcoma, transmissible venereal tumor, schwannoma
• Leukocytosis

  • •
    Neutrophilic
  • •
    Eosinophilic
• Thrombocytopenia

  • •
    Increased consumption
  • •
    Decreased production (bone marrow neoplasia)
  • •
    Increased destruction (immune-mediated thrombocytopenia)

• Thrombocytosis

• Thrombocyte hyperaggregability/hypercoagulability

• Pancytopenia

• Coagulation disorders

  • •
    Disseminated intravascular coagulation (DIC)
  • •
    Coagulation-activating substances produced by tumor

• Hyperproteinemia/hyperglobulinemia

Endocrine

• Hypercalcemia of malignancy

• Hypoglycemia

• Syndrome of inappropriate antidiuretic hormone (ADH) secretion

  • •
    Hyponatremia, serum
  • •
    Hypoosmolality, urine
  • •
    Hyperosmolality

• Hyperestrogenism (Sertoli cell tumor)

Gastrointestinal

• Gastroduodenal ulceration

  • •
    Mast cell tumors, gastrinoma

• Cancer cachexia

Renal

• Glomerulonephritis

• Hypercalcemic nephropathy

Cutaneous

• Superficial necrolytic dermatitis

• Nodular dermatofibrosis

• Feline paraneoplastic alopecia

Neuromuscular

• Myasthenia gravis

  • •
    Dogs with thymoma
• Peripheral neuropathy

  • •
    Multiple myeloma, lymphoma, various carcinomas and sarcomas

Hypertrophic Osteodystrophy

• Space-occupying mass in thorax or rarely abdomen

Sarcomas

Classification of Soft Tissue Sarcomas

• Fibrosarcoma

• Mast cell tumor

• Undifferentiated sarcoma

• Hemangiosarcoma

• Hemangiopericytoma (peripheral nerve-sheath tumor)

• Myxosarcoma

• Leiomyosarcoma

• Malignant fibrous histiocytoma

• Schwannoma

• Neurofibrosarcoma

• Synovial cell sarcoma

• Rhabdomyosarcoma

• Liposarcoma

• Vaccine-associated fibrosarcoma (cats)

Clinical Findings for Hemangiosarcoma

• Older dogs and cats

• Many potential sites of origin

  • •
    Spleen
  • •
    Right atrium
  • •
    Subcutis
  • •
    Pericardium
  • •
    Liver
  • •
    Muscle
  • •
    Lung
  • •
    Skin
  • •
    Bone
  • •
    Kidney
  • •
    Central nervous system
  • •
    Peritoneum
  • •
    Oral cavity
  • •
    Nasal cavity
  • •
    Eye
  • •
    Retroperitoneum

• Hemoabdomen

• Pericardial effusion

• Cardiac tamponade

• Sudden death

• Anorexia, vomiting

• Lethargy

• Right-sided heart failure

• Muffled heart sounds

• Arrhythmias

• Neurologic signs (may metastasize to brain)

Thyroid Neoplasms

Classification and Clinical Findings

Cats

• Hyperthyroidism: functional thyroid tumors

  • •
    Thyroid adenoma
  • •
    Thyroid adenocarcinoma

Dogs

Nonfunctional Tumors (90%)

• Thyroid adenoma

• Thyroid adenocarcinoma

  • •
    Swelling or mass in neck
  • •
    Dyspnea
  • •
    Cough
  • •
    Lethargy
  • •
    Dysphagia
  • •
    Regurgitation
  • •
    Anorexia
  • •
    Weight loss
  • •
    Horner syndrome
  • •
    Change in bark
  • •
    Facial edema

Functional Tumors (10%)

• Thyroid adenoma

• Thyroid adenocarcinoma

  • •
    Swelling or mass in neck
  • •
    Polyphagia/weight
  • •
    Hyperactivity
  • •
    Polyuria/polydipsia
  • •
    Panting
  • •
    Change in behavior (aggression)

Tumors

Bone and Joint Tumors, Classification

• Canine osteosarcoma

  • Appendicular
  • Skull
  • Scapular
  • Pelvic
  • Ribs
  • Vertebral
  • Nasal and paranasal

• Chondrosarcoma

• Fibrosarcoma

• Hemangiosarcoma

• Multilobular osteochondrosarcoma

• Osteoma

• Canine multiple cartilaginous exostoses

• Feline osteosarcoma

• Feline multiple cartilaginous exostoses

• Metastatic bone tumors

  • Transitional cell carcinoma
  • Prostatic adenocarcinoma
  • Mammary carcinoma
  • Thyroid carcinoma
  • Pulmonary carcinoma
  • Nasal carcinoma
  • Apocrine gland, anal sac adenocarcinoma
  • Renal tumors
  • Others
• Primary joint tumors

  • Synovial cell sarcoma
  • Histiocytic sarcoma
  • Malignant fibrous histiocytoma
  • Synovial myxoma
  • Myxosarcoma
  • Osteosarcoma
  • Fibrosarcoma
  • Chondrosarcoma
  • Hemangiosarcoma
  • Liposarcoma
  • Rhabdomyosarcoma
  • Undifferentiated sarcoma

Hematopoietic Tumors, Classification

Lymphoma

Feline

• Alimentary

• Multicentric

• Mediastinal/thymic

• Nasal

• Renal

• Other

• Feline leukemia virus (FeLV) associated

Canine

• Multicentric

• Others (alimentary, mediastinal, cutaneous)

Lymphoid Leukemia

• Acute lymphoblastic leukemia (in cats, often associated with FeLV infection)

• Chronic lymphocytic leukemia

Nonlymphoid Leukemias and Myeloproliferative Disorders

• Acute myelogenous leukemia (myeloblastic)

• Acute myelomonocytic leukemia (myeloblasts/monoblasts)

• Acute monocytic leukemia (monoblasts)

• Acute megakaryoblastic leukemia (megakaryoblasts)

• Erythroleukemia (erythroblasts)

Chronic Myeloproliferative Disorders

• Chronic myelogenous leukemia (neutrophils, late precursors)

• Primary thrombocythemia (platelets)

• Basophilic leukemia (basophils and precursors)

• Eosinophic leukemia (eosinophils and precursors)

• Polycythemia vera (erythrocytes)

Plasma Cell Neoplasms

• Multiple myeloma

• Solitary plasmacytoma

• IgM (Waldenström macroglobulinemia)

Mast Cell Tumor (MCT) Disease, Clinical Findings

Clinical Appearance and Location of MCTs

• Extremely variable in appearance

• Soft, fluctuant, firm, discrete, diffuse, small, large, solitary, multiple, haired, hairless, dermal, or subcutaneous

• Erythema, bruising, ulceration

• On trunk most often; also perineum, extremities, head, neck

• Rarely oral cavity, nasal cavity, larynx, conjunctiva

Systemic Signs of Disseminated Mastocytosis

• Gastrointestinal ulceration

• Abdominal discomfort

• Vomiting

• Melena

• Hypotension

• Coagulation abnormalities

• Acute or chronic blood loss anemia

Oral Cavity Tumors, Differential Diagnosis

Malignant Neoplasms

• Melanoma

• Squamous cell carcinoma

• Fibrosarcoma

• Osteosarcoma

• Lingual carcinoma or sarcoma

• Histiocytic sarcoma

• Lymphoma

• Mast cell tumor

Benign Neoplasms

• Epulides (acanthomatous ameloblastoma)

  • •
    Fibromatous
  • •
    Ossifying
  • •
    Acanthomatous (squamous): may be invasive but does not metastasize

• Papillomas: self-limiting

• Fibroma

• Lipoma

• Chondroma

• Osteoma

• Odontoma

• Cementoma

• Plasmacytoma

• Hemangioma

• Hemangiopericytoma

• Histiocytoma

• Eosinophilic granuloma

Skin and Subcutaneous Tumors

Epithelial Tumors

• Sebaceous gland adenoma/adenocarcinoma

• Squamous cell carcinoma

  • •
    Canine cutaneous squamous cell carcinoma
  • •
    Canine nasal planum squamous cell carcinoma
  • •
    Canine digital squamous cell carcinoma
  • •
    Feline cutaneous squamous cell carcinoma
  • •
    Feline multicentric squamous cell carcinoma in situ (Bowen disease)

• Trichoepithelioma

• Intracutaneous cornifying epithelioma

• Basal cell tumors

  • •
    Benign tumors
  • •
    Basal carcinoma

• Trichoblastoma

• Pilomatricoma

• Papilloma

• Perianal gland tumors (hepatoid gland tumors)

• Sweat gland tumors (apocrine gland tumors)

• Ceruminous gland tumors

• Anal sac, apocrine gland tumors

• Follicular stem cell carcinoma

Round Cell Tumors

• Lymphoma

• Mast cell tumor

• Histiocytoma

• Transmissible venereal tumor (TVT)

• Plasmacytoma

Melanocytic Tumors

• Melanoma

  • •
    Benign (typically melanomas of haired skin and eyelids)
  • •
    Malignant (typically those of digit or mucocutaneous junctions)

Urogenital Tumors, Classification

Kidney

• Lymphoma (most common renal tumor in cats)

• Primary renal carcinoma, adenoma/adenocarcinoma

• Cystadenocarcinoma with concurrent nodular dermatofibrosis in German Shepherds

• Tumors of embryonic origin (e.g., Wilm tumor)

• Nephroblastoma

• Transitional cell carcinoma

Urinary Bladder

• Older female dogs, West Highland White Terrier, Scottish Terriers, Beagles, Dachshunds, Shetland Sheepdogs

• Transitional cell carcinoma

• Squamous cell carcinoma

• Leiomyosarcoma

• Leiomyoma

• Rhabdomyosarcoma

• Metastatic neoplasia

  • •
    Hemangiosarcoma
  • •
    Lymphoma
  • •
    Extension of prostate neoplasia

Prostate

• Prostatic adenocarcinoma

• Transitional cell carcinoma

Penis and Prepuce

• Prepuce affected by tumors of haired skin seen elsewhere

• Penile

  • •
    Transmissible venereal tumor
  • •
    Others

Testicular Neoplasia

• Cryptorchid dogs are 13.6 times more likely to develop Sertoli cell tumor or seminoma

• Sertoli cell tumor (25–50% are functional and cause hyperestrogenemia)

• Leydig cell (interstitial) tumor

• Seminoma

Vagina and Vulva

• Leiomyoma

• Fibroleiomyoma

• Fibroma

• Polyps

• Lipoma

• Leiomyosarcoma (rare)

• Transmissible venereal tumor (TVT)

Uterus

• Leiomyoma

• Leiomyosarcoma

• Uterine adenocarcinoma

Ovary

Epithelial Tumors (50% of ovarian tumors)

• Papillary adenoma

• Cystadenoma

• Papillary adenocarcinoma

• Undifferentiated adenocarcinoma

Germ Cell Tumors (10% of ovarian tumors)

• Dysgerminoma

• Teratoma

• Teratocarcinoma

Sex-Cord Stromal Tumors (40% of ovarian tumors)

• Granulosa cell tumor

• Benign thecoma

• Benign luteoma

Mammary Gland

• Fibroadenoma (mixed mammary tumor)

• Solid carcinomas

• Tubular adenocarcinoma

• Sarcoma

• Inflammatory carcinomas

• Feline mammary adenocarcinomas

SECTION XI. Neurologic and Neuromuscular Disorders

• Brain Disease, Congenital or Hereditary

• Cognitive Dysfunction

• Cranial Nerve (CN) Deficits

• Head Tilt

• Inflammatory Disease of the Nervous System

• Intracranial Neoplasms

• Myasthenia Gravis

• Myositis and Myopathies

• Neurologic Examination

• Paroxysmal Disorders Confused with Epileptic Seizures

• Peripheral Neuropathies

• Spinal Cord Disease

• Spinal Cord Lesions

• Systemic Disease

• Vestibular Disease

Brain Disease, Congenital or Hereditary

Differential Diagnosis

Congenital Malformations

• Failure of normal closure of neural tube: vary in severity from clinically inapparent (agenesis of corpus callosum) to severe (anencephaly)

• Lissencephaly: failure of normal migration of neurons in development of cerebral cortex; leads to abnormal appearance of sulci and gyri (most often seen in Lhasa Apso)

• Cerebellar hypoplasia: seen most often in cats after in utero panleukopenia infection; rarely seen with parvovirus infection of developing cerebellum in dogs; may be isolated malformation without infection

• Chiari-like malformations: protrusion of cerebellar vermis through foramen magnum (Cavalier King Charles Spaniel, other dog breeds)

• Hydrocephalus: congenital hydrocephalus seen most often in toy and brachycephalic breeds; suggests hereditary basis; often congenital stenosis or aplasia of mesencephalic aqueducts

• Inborn errors of metabolism (hereditary): young, purebred animals with diffuse, symmetric signs of brain disease

  • •
    Organic acidurias
  • •
    Spongiform encephalopathies: may be hereditary or acquired (transmissible) disease
  • •
    Polioencephalopathies: metabolic defects that affect gray matter
  • •
    Neuroaxonal dystrophy: spheroids causing swelling within axons
  • •
    Leukoencephalopathies: disorders of myelin; affect white matter; often affect cerebellum and long tracts leading to tremors and dysmetria
  • •
    Lysosomal storage diseases: accumulation of metabolic products in lysosomes
  • •
    Ceroid lipofuscinosis: accumulation of proteins in lysosomes
  • •
    Neonatal encephalopathy: hereditary disease of Standard Poodles

Movement Disorders

• Hereditary cerebellar hypoplasia

• Multisystem degeneration: diseases of cerebellum and basal ganglia—progressive neuronal abiotrophy of Kerry Blue Terriers and Chinese Crested dogs

• Dyskinesis and dystonias

• Paroxysmal dyskinesias (“Scotty cramp” or idiopathic cerebellitis)—Scottish Terriers

Cognitive Dysfunction

Clinical Findings

• Disorientation

• Sleep/wake cycle alterations

• House soiling problems

• Change in activity levels

  • •
    Increased
  • •
    Stereotypic
  • •
    Decreased

• Agitation

• Anxiety

• Altered responsiveness to stimuli

  • •
    Heightened
  • •
    Reduced
• Changes in appetite

  • •
    Increased
  • •
    Decreased

• Decreased ability to perform learned tasks

• Changes in interaction with owners

Cranial Nerve (CN) Deficits

Clinical Findings

CN I (Olfactory)

• Loss of ability to smell

CN II (Optic)

• Loss of vision, loss of menace response, dilated pupil, loss of papillary light reflex (direct and consensual)

CN III (Oculomotor)

• Loss of papillary light reflex on affected side (even if light shone in opposite eye), dilated pupil, ptosis, ventrolateral strabismus

CN IV (Trochlear)

• Slight dorsomedial eye rotation

CN V (Trigeminal)

• Atrophy of temporalis and masseter muscles, loss of jaw tone and strength, dropped jaw (if bilateral), analgesia of innervated areas

CN VI (Abducens)

• Medial strabismus, impaired lateral gaze, poor retraction of globe

CN VII (Facial)

• Lip, eyelid, and ear droop; loss of ability to blink; loss of ability to retract lip; possibly decreased tear production

CN VIII (Vestibulocochlear)

• Ataxia, head tilt, nystagmus, deafness, positional strabismus

CN IX (Glossopharyngeal)

• Loss of gag reflex, dysphagia

CN X (Vagus)

• Loss of gag reflex, laryngeal paralysis, dysphagia, megaesophagus

CN XI (Accessory)

• Atrophy of trapezius, sternocephalicus, and brachiocephalicus muscles

CN XII (Hypoglossal)

• Loss of tongue strength, inability to retract tongue if bilateral, atrophy of tongue

Head Tilt

Differential Diagnosis

Peripheral Vestibular Disease

• Otitis media/interna

• Feline idiopathic vestibular disease

• Geriatric canine vestibular disease

• Feline nasopharyngeal polyps

• Middle ear tumor

  • •
    Ceruminous gland adenocarcinoma
  • •
    Squamous cell carcinoma

• Trauma

• Aminoglycoside ototoxicity/chemical ototoxicity

• Hypothyroidism (possibly)

Central Vestibular Disease

• Trauma/hemorrhage

• Infectious inflammatory disease

  • •
    Rocky Mountain spotted fever
  • •
    Feline infectious peritonitis (FIP)
  • •
    Others

• Granulomatous meningoencephalitis

• Neoplasia

• Vascular infarct

• Thiamine deficiency

• Metronidazole toxicity

Inflammatory Disease of the Nervous System

Differential Diagnosis

• Steroid-responsive meningitis-arteritis (steroid-responsive suppurative meningitis) (juvenile to young adult large breed dogs: Bernese Mountain Dogs, Boxers, German Shorthaired Pointers, Nova Scotia Duck Tolling Retrievers)

• Granulomatous meningoencephalitis

  • •
    Idiopathic inflammatory brain disease of dogs
  • •
    Most commonly in small breed dogs
• Pug meningoencephalitis

  • •
    Necrotizing meningoencephalitis of cerebral cortex
  • •
    Maltese and Yorkshire terrier also
• Feline polioencephalomyelitis

  • •
    Young cats, progressive course

• Feline immunodeficiency virus (FIV) encephalopathy

• Bacterial meningitis and myelitis

  • •
    Staphylococcus aureus
  • •
    Staphylococcus epidermidis
  • •
    Staphylococcus albus
  • •
    Pasteurella multocida
  • •
    Actinomyces
  • •
    Nocardia
  • •
    Others

• Canine distemper virus

• Rabies

• Feline infectious peritonitis (FIP)

• Toxoplasmosis

• Neosporosis

• Borreliosis

• Mycotic infections

  • •
    Cryptococcus neoformans, C. gattii
  • •
    Other disseminated systemic mycoses
• Rickettsial diseases

  • •
    Rocky Mountain spotted fever
  • •
    Ehrlichiosis
  • •
    Ehrlichia ewingii, Anaplasma phagocytophilia
• Parasitic meningitis, myelitis, encephalitis

  • •
    Aberrant parasite migration

Intracranial Neoplasms

Differential Diagnosis

Meningioma

• Benign tumor of cells of meninges

Neuroepithelial Tumors (Gliomas)

• Astrocytomas

• Oligodendrogliomas

• Choroid plexus tumors (choroid plexus papilloma, ependymal tumor)

Central Nervous System (CNS) Lymphoma

• Primary: neoplasia of native CNS lymphocytes

• Secondary: metastasis of systemic lymphoma

Metastatic Neoplasia to CNS

• Local invasion: nasal adenocarcinoma

• Hematogenous spread: melanoma, hemangiosarcoma, lymphosarcoma

• Many other neoplasms may metastasize to CNS.

Pituitary Tumors

• Functional tumors of pars distalis or pars intermedius: cause pituitary-dependent hyperadrenocorticism; generally cause little damage to surrounding tissue

• Pituitary macrotumor

Myasthenia Gravis

• Congenital myasthenia gravis: inherited deficiency of acetylcholine receptors at presynaptic membranes of skeletal muscle.

• Acquired myasthenia gravis: antibodies made against nicotinic acetylcholine receptors of skeletal muscle.

Clinical Findings

• Appendicular muscle weakness

  • •
    Worsens with exercise
  • •
    Improves with rest
  • •
    Tetraplegia

• Mentation, postural reactions, reflexes normal

• Megaesophagus

  • •
    Salivation
  • •
    Regurgitation

• Dysphagia

• Ventroflexion

• Urinary bladder distension

• Hoarse bark or meow

• Persistently dilated pupils

• Facial muscle weakness

• Aspiration pneumonia

• Respiratory weakness

Myositis and Myopathies

Differential Diagnosis

Inflammatory Myopathies

• Masticatory myositis

  • •
    Immunoglobulin G (IgG) antibodies to type 2M myofibers
  • •
    German Shepherd, retrievers, and Doberman Pinscher predisposed
  • •
    Young to middle-aged dogs
• Canine idiopathic polymyositis

  • •
    Large-breed dogs predisposed

• Feline idiopathic polymyositis

• Dermatomyositis

  • •
    Herding breeds, especially Shetland Sheepdog and Collie
• Protozoal myositis

  • •
    Toxoplasma gondii
  • •
    Neospora caninum Hepatozoon, Babesia, Leishmania, or Trypanosoma infection

• Bacterial myositis Clostridium, Leptospira, Ehrlichia, Rocky Mountain spotted fever

• Extraocular myositis (dogs)

• Feline immunodeficiency virus

Metabolic Myopathies

• Glucocorticoid excess

  • •
    Hyperadrenocorticism
  • •
    Exogenous corticosteroids

• Hypothyroidism

• Hypoadrenocorticism

• Hypokalemic polymyopathy (cat)

  • •
    Increased urinary excretion
  • •
    Decreased dietary intake

• Mitochondrial myopathies

• Lipid storage myopathies

• Glycogen storage disorders

• Malignant hyperthermia

• Hyperkalemic periodic paralysis (American Pit Bull Terrier)

Inherited Myopathies

• Muscular dystrophy

  • •
    Hereditary Labrador Retriever muscular dystrophy
  • •
    Also German Shorthaired Pointer, Rottweiler, others
  • •
    Maine Coon, Siamese, Devon Rex, Sphynx, others
• Myotonia

  • •
    Chow Chow, Staffordshire Bull Terrier, Labrador Retriever, Rhodesian Ridgeback, Great Dane, others
• Malignant hyperthermia

  • •
    Hypermetabolic disorder of skeletal muscle
  • •
    Genetic defect in intracellular calcium homeostasis

• Inherited myopathy of Great Danes

• Centronuclear myopathy

  • •
    Labrador Retriever
• Episodic/Exercise-induced collapse

  • •
    Labrador Retriever

• Exertional rhabdomyolysis

Neurologic Examination

Components

Mental State

• Normal

• Depression

• Stupor

• Coma

• Agitation

• Delirium

Posture

• Normal, upright

• Head tilt

• Wide-based stance

• Recumbent

• Extensor posturing

• Opisthotonus

• Pleurothotonus

Gait

• Proprioceptive deficits

• Paresis

• Circling

• Ataxia

• Dysmetria

• Lameness

Postural Reactions

• Conscious proprioception

• Hopping

• Wheelbarrowing

• Hemiwalking

• Extensor postural thrust

Muscle Tone

• Atrophy

• Decreased muscle tone (lesions of lower motor neurons)

• Increased muscle tone (lesions of upper motor neurons)

• Schiff-Sherrington posture (increased muscle tone and hyperextension of thoracic limbs)

Spinal Reflexes

• Absent, depressed, normal, or exaggerated

• Thoracic limb withdrawal (sixth cervical [C6], C7, C8, first thoracic [T1])

• Biceps (C6-C8) and Triceps (C7-T2) reflexes

• Patellar (fourth lumbar [L4], L5, L6)

• Pelvic limb withdrawal (L6, L7, first sacral [S1])

• Sciatic (L6, L7, S1)

• Cranial tibial (L6, L7)

• Perineal (S1, S2, S3, pudendal nerve)

• Bulbourethral (S1, S2, S3, pudendal nerve)

• Panniculus (response absent caudal to spinal cord lesion, used at T3-L3)

• Crossed extensor reflex (indicative of UMN disease)

• Cutaneous trunci reflex

Sensation and Pain

• Superficial pain

• Deep pain

• Hyperesthesia

Urinary Tract Function

 

Cranial Nerves

 

Paroxysmal Disorders Confused with Epileptic Seizures

Differential Diagnosis

Syncope (reduced cerebral blood flow)

• Cardiac arrhythmias

• Hypotension

Episodic Weakness

• Hypoglycemia

• Low blood cortisol

• Electrolyte disturbances

Myasthenia Gravis

 

Acute Vestibular “Attacks”

 

Movement Disorders

• Episodic falling

• Scotty cramp

• Head bobbing

• Dyskinesias

Sleep Disorders

• Narcolepsy

• Cataplexy

Obsessive Compulsive Disorder

 

Peripheral Neuropathies

• Clinical signs depend on the nerve affected and the severity of the lesion.

Differential Diagnosis

Focal Disease

Trauma

• Mechanical blows

• Fractures

• Pressure

• Stretching

• Laceration

• Injection of agents into nerves

Peripheral Nerve Tumors

• Schwannoma

• Neurofibroma

• Neurofibrosarcoma

• Lymphoma

Facial Nerve Paralysis

• Otitis media

• Trauma

• Neoplasia

• Foreign body (e.g., grass awn)

• Nasopharyngeal polyp in cats

• Hypothyroidism

• Idiopathic

Trigeminal Nerve Paralysis

• Bilateral, idiopathic disorder, often self-limiting

• Middle-aged to older dogs, rarely cats

Idiopathic Peripheral Vestibular Disease

 

Hyperchylomicronemia

• Leads to xanthomas in skin

• May compress peripheral nerves

Ischemic Neuromyopathy

• Caudal aortic thromboembolism

Generalized Chronic Polyneuropathies

• Idiopathic

• Metabolic disorders

  • •
    Diabetes mellitus
  • •
    Hypothyroidism
• Paraneoplastic syndromes

  • •
    Insulinoma
  • •
    Other tumors

• Systemic lupus erythematosus (SLE) or other immune-mediated disease

• Chronic organophosphate toxicity

• Ehrlichiosis

Generalized Acute Neuropathies

• Acute polyradiculoneuritis (“coonhound paralysis”)

• Neospora polyradiculoneuritis (puppies)

• Disorders of neuromuscular junction

  • •
    Botulism
  • •
    Tick paralysis
  • •
    Myasthenia gravis

• Protozoal polyradiculoneuritis

• Dysautonomia

Developmental/Congenital Neuropathies

• Loss of motor neurons—Cairn Terrier, German Shepherd, English Pointer, Rottweiler, Swedish Lapland, Brittany Spaniel

• Loss of peripheral axons—German Shepherd, Alaskan Malamute, Birman cat, Rottweiler, Boxer, Dalmatian

• Schwann cell dysfunction—Golden Retriever, Tibetan Mastiff

• Loss of sensory neuron of axon and laryngeal nerves—Dachshund, English Pointer, Shorthaired Pointer, Bouvier des Flandres, Siberian Husky

• Inborn errors of metabolism

  • •
    Hyperchylomicronemia (cat)
  • •
    Hyperoxaluria type 2 (shorthaired cat)
  • •
    α-l-Fucosidosis (English Springer Spaniel)
  • •
    Atypical GM2 gangliosidosis (cat)
  • •
    Globoid cell leukodystrophy
  • •
    Niemann-Pick disease (Siamese)
  • •
    Glycogen storage disease (Norwegian forest cat)

Spinal Cord Disease

Differential Diagnosis

Acute

• Trauma

• Hemorrhage/coagulopathy

• Infarction

• Type I intervertebral disk herniation

• Fibrocartilaginous embolism

• Atlantoaxial subluxation

Subacute/Progressive

• Discospondylitis

• Noninfectious inflammatory diseases

  • •
    Corticosteroid-responsive meningitis/arteritis
  • •
    Granulomatous meningoencephalitis
  • •
    Feline polioencephalomyelitis
• Infectious inflammatory diseases

  • •
    Bacterial, fungal, rickettsial, protothecal, protozoal, nematodiasis

• Distemper myelitis

• Feline infectious peritonitis (FIP) meningitis/myelitis

Chronic Progressive

• Neoplasia

• Type II intervertebral disk protrusion

• Degenerative myelopathy

• Cauda equina syndrome

• Cervical vertebral malformation/malarticulation (wobbler syndrome)

• Lumbosacral vertebral canal stenosis

• Spondylosis deformans

• Hypervitaminosis A (cats)

• Dural ossification

• Diffuse idiopathic skeletal hyperostosis

• Synovial cyst

Progressive in Young Animals

• Neuronal abiotrophies and degenerations

• Metabolic storage diseases

• Atlantoaxial luxation

• Congenital vertebral anomalies

Congenital (Constant)

• Spinal bifida

• Congenital dysgenesis of Manx cats

• Spinal dysraphism

• Hereditary ataxia

• Pilonidal, epidermoid, and dermoid cysts

• Syringomyelia/hydromyelia

Spinal Cord Lesions

Localization

Cranial Cervical Lesion (C1-C5)

• Upper motor neuron (UMN) signs in rear limbs

• UMN signs in forelimbs

Caudal Cervical Lesion (C6-T2)

• UMN signs in rear limbs

• Lower motor neuron (LMN) signs in forelimbs

Thoracolumbar Lesion (T3-L3)

• UMN signs in rear limbs

• Normal forelimbs

Lumbosacral Lesion (L4-S3)

• LMN signs in rear limbs

• Loss of perineal sensation and reflexes

• Normal forelimbs

Sacral Lesion (S1-S3)

• Normal forelimbs

• Normal patellar reflexes

• Loss of sciatic function

• Loss of perineal sensation and reflexes

Systemic Disease

Neurologic Manifestations

Oxygen Deprivation

Vascular Disease

Ischemia

• Thromboembolic disease

• Shock

• Cardiac disease

Hemorrhage (anemia)

• Vessel rupture secondary to hypertension

• Coagulopathy

• Vasculitis

Anesthetic Accidents

• Hypotension

• Cardiac arrhythmia

• Extensive blood loss

• Hypercapnia

• Hypoxemia

Hypoxia

• Pulmonary disease

• Decreased oxygen transport

• Heart failure

Hypertension

 

Hypoglycemia

Decreased Output or Metabolism

• Primary liver disease

• Malnutrition

• Thiamine deficiency

Increased Uptake

Hyperinsulinemia

• Islet cell tumors

• Insulin overdose

Non–Islet Cell Neoplasia

• Hepatoma

• Leiomyoma

Excessive Metabolism

• Sepsis

• Breed or activity-related

Increased Uptake of Amino Acids by Extrahepatic Tissues

 

Water and Ionic Imbalances

Water

Hypoosmolar States (Retention of Free Water)

• Hyponatremia

Hyperosmolar States (Loss of Free Water)

• Hypernatremia (diabetes insipidus)

• Hyperglycemia (diabetes mellitus)

Ions (Excess or Deficiency)

• Calcium

• Potassium

Endogenous Neurotoxins

Renal Toxins

 

Hepatoencephalopathy

 

Endocrine Disease

Adrenal

• Hyperadrenocorticism

• Hypoadrenocorticism

Adrenergic Dysregulation

• Pheochromocytoma

Thyroid

• Hypothyroidism

  • •
    Myxedema
  • •
    Neuromyopathy
• Thyrotoxicosis

  • •
    Hyperthyroidism
  • •
    Iatrogenic

Exogenous Neurotoxins

• Plant toxins

• Sedative depressant drugs (e.g., antiepileptic drugs)

• Heat stroke

Remote Neurologic Manifestations of Cancer

• Metastasis to the nervous system

• Vascular accidents and infection

• Adverse effects of therapy

• Paraneoplastic syndromes

Vestibular Disease

Clinical Findings

Central and Peripheral Vestibular Disease

• Head tilt to side of lesion

• Circling/falling/rolling to side of lesion

• Vomiting, salivation

• Incoordination

• Ventral strabismus on side of lesion (±)

• Nystagmus, fast phase away from lesion

• Nystagmus may intensify with changes in body position.

Peripheral Vestibular Disease

• Nystagmus is horizontal or rotatory.

• No change in nystagmus direction with changes in head position

• Postural reactions and proprioception normal

• Concurrent Horner syndrome, cranial nerve VII paralysis with middle/inner ear involvement; other cranial nerves normal

Central Vestibular Disease

• Nystagmus horizontal, rotatory, or vertical

• Nystagmus direction may change direction with change in head position.

• Abnormal postural reactions and proprioception may be seen on side of lesion.

• Multiple cranial nerve deficits may be seen.

Paradoxical Vestibular Syndrome (Cerebellar Lesion)

• Head tilt and circling away from side of lesion

• Fast phase nystagmus toward the lesion

• May exhibit vertical nystagmus

• Abnormal postural reactions on side of lesion

• ± Multiple cranial nerve deficits on side of lesion

• ± Hypermetria, truncal sway, and head tremor

SECTION XII. Ocular Disorders

• Anisocoria

• Blindness, Acute

• Corneal Color Changes

• Eyelids and Periocular Skin

• Nonhealing Corneal Erosions (Ulcers) in Dogs

• Ocular Manifestations of Systemic Diseases

• Ocular Neoplasia

• Red Eye

• Retinal Detachment

• Uveitis

Anisocoria

Differential Diagonosis

Nonneurologic Causes of Anisocoria

Conditions That Cause Miosis

• •Anterior uveitis
• •Corneal ulcers and lacerations (reflex miosis mediated by trigeminal nerve)

Conditions That Cause Mydriasis

• •Iris atrophy
• •Iris hypoplasia
• •Glaucoma
• •Iridal tumors (e.g., melanoma) that infiltrate iridal musculature
• •Unilateral retinal disease (e.g., retinal detachment)
• •Severe chorioretinitis that affects a larger area on one eye than the other
• •Unilateral optic neuritis or optic nerve neoplasia
• •Orbital neoplasia, retrobulbar abscess, cellulitis

Pharmacologic Causes of Anisocoria

Drugs That Cause Miosis (usually agents used for management of glaucoma)

• •Pilocarpine
• •Demecarium bromide
• •Synthetic prostaglandins such as latanoprost

Drugs That Cause Mydriasis

• •Tropicamide, atropine
• • Ocular contact with toxins like jimsonweed (Datura stramonium)
• •Ocular decongestants like phenylephrine

Neurologic Causes of Anisocoria

Afferent Lesions

• Anisocoria is reduced or abolished in darkness as both pupils dilate. This is because the stimulus producing the anisocoria, light causing constriction of the normal pupil, is eliminated.

  • •
    Unilateral retinal or prechiasmal optic nerve lesion
  • •
    Unilateral optic tract lesion
  • •
    Optic chiasm lesion

Efferent Lesions

• Parasympathetic efferent lesions (In dogs, preganglionic efferent nerves are purely parasympathetic and postganglionic nerves are mixed. In cats both nerves are purely parasympathetic.)

  • •
    Lesions of the nucleus of CN III, the preganglionic fibers, or the ganglion itself
• Sympathetic efferent lesions (Loss of sympathetic tone to the eye is known as Horner syndrome, is always ipsilateral to lesion, and features miosis, ptosis, protrusion of the third eyelid, and enophthalmos.)

  • •
    Head, neck, or chest trauma
  • •
    Brachial plexus avulsion
  • •
    Intracranial, mediastinal, or intrathoracic neoplasia
  • •
    Otitis media/interna
  • •
    Injury to the ear during ear flushing
  • •
    Idiopathic (Golden Retriever and Collie may be predisposed.)

Blindness, Acute

Differential Diagnosis, Dogs and Cats

Cornea

• Edema (glaucoma, trauma, endothelial dystrophy, immune-mediated keratitis, neurotropic keratitis, anterior uveitis)

• Melanin (entropion, ectropion, lagophthalmos, facial nerve paralysis, keratoconjunctivitis sicca, pannus)

• Cellular infiltrate (bacterial, viral, fungal)

• Vascular invasion (exposure keratitis)

• Fibrosis (scar formation)

• Dystrophy (lipid, genetic)

• Symblepharon (conjunctiva adhered to cornea)

Aqueous Humor

• Fibrin (anterior uveitis: many etiologies)

• Hyphema (trauma, coagulopathies, neoplasia, systemic hypertension, retinal detachment)

• Hypopyon (immune-mediated, lymphoma, systemic fungal infection, toxoplasmosis, FIP, protothecosis, brucellosis, bacterial septicemia)

• Lipemic (hyperlipidemia with concurrent blood-aqueous barrier disruption [uveitis])

Lens

• Cataracts (genetic, diabetes, retinal degeneration, hypocalcemia, electric shock, chronic uveitis, lens luxation, metabolic, toxic, traumatic, nutritional)

Vitreous

• Hemorrhage (trauma, systemic hypertension, retinal detachment, neoplasia, coagulopathy)

• Hyalitis (numerous infectious agents, penetrating injury)

Retina

• Retinopathy (glaucoma, sudden acquired retinal degeneration [SARD], progressive retinal atrophy, central progressive retinal atrophy, feline central retinal atrophy, toxicity, taurine deficiency in cats, vitamin E deficiency in dogs, enrofloxacin toxicity in cats)

• Chorioretinitis (systemic mycoses, ehrlichiosis, RMSF, canine distemper, toxoplasmosis, FIP, protothecosis, brucellosis, bacterial septicemia, intraocular larval migrans, neoplasia)

• Retinal detachment (neoplasia, retinal dysplasia, hereditary/congenital, exudative/transudative disorders such as systemic hypertension or infection-induced inflammatory disease)

Lesions that Prevent Transmission of the Image (optic nerve disease)

• Viruses (canine distemper, feline infectious peritonitis [FIP])

• Systemic diseases (neoplasia, traumatic avulsion of optic nerve, granulomatous meningoencephalitis, hydrocephalus, optic nerve hypoplasia, immune-mediated optic neuritis, systemic mycoses)

Lesions that Prevent Interpretation of the Visual Message

• Canine distemper, FIP, toxoplasmosis, granulomatous meningoencephalitis, systemic mycoses, trauma, heat stroke, hypoxia, hydrocephalus, hepatoencephalopathy, neoplasia, storage diseases, postictal, meningitis

Corneal Color Changes

Diagnostic Tests

Red (blood vessels)

• •Mechanism is chronic irritation
• •Fluorescein stain, Schirmer tear test (STT), palpebral and corneal reflexes

“Fluffy” Blue (stromal edema)

• •Mechanisms are endothelial or epithelial dysfunction
• •Fluorescein stain, intraocular pressure (IOP), flare, check for lens luxation

“Wispy” Gray (stromal scar)

• •Mechanism is previous (inactive) inflammation
• •Fluorescein stain

“Sparkly” White (lipid/mineral accumulation)

• •Mechanisms are dystrophy, degeneration, or hyperlipidemia
• •Flourescein stain, systemic lipid analysis

Black (pigmentation)

• •Mechanism is chronic irritation
• •Fluorescein stain, STT

“Punctate” Tan (keratinic precipitates or staphyloma)

• •Mechanism is uveitis
• •IOP, flare, systemic disease testing

Yellow-Green (inflammatory cell infiltration)

• •Inflammation (usually septic)
• •Fluorescein stain, cytology, culture and sensitivity testing, polymerase chain reaction (PCR)

Eyelids and Periocular Skin

Differential Diagnosis

Infectious Blepharitis

Bacterial Blepharitis

• •Usually Staphylococcus spp.
• •External hordeolum or stye—infection of the glands of Zeis or Moll
• •Internal hordeolum—infection of the meibomian glands
• •Chalazion—meibomian secretions thicken and obstruct the duct, leading to glandular rupture and lipogranuloma formation

Fungal Blepharitis

• •Dermatophytes (Microsporum canis, Microsporum gypseum, Trichophyton mentagrophytes)
• • Malassezia pachydermatitis—most dogs with Malassezia dermatitis have concurrent dermatoses, in cats Malassezia infection is linked to systemic disease like diabetes, retroviral infection, internal neoplasia

Parasitic Blepharitis

• •Demodecosis
• •Feline herpetic ulcerative dermatitis

Allergic Blepharitis

• •Atopic dermatitis
• •Cutaneous adverse food reaction (food allergy)

Metabolic/Nutritional Blepharitis

• •Zinc-responsive dermatosis
• •Superficial necrolytic dermatitis (hepatocutaneous disease)

Immune-Mediated Blepharitis

• •Pemphigus foliaceus
• •Pemphigus erythematosus
• •Systemic lupus erythematosus
• •Erythema multiforme

Iatrogenic Blepharitis

• •Adverse reactions to topical medications

Pigmentary Changes Involving the Eyelid

• •Lentigo simplex of orange cats (black macules, not pathogenic)
• •Vitiligo (hypopigmentation)
• •Uveodermatologic (Vogt-Koyanagi-Harada-like) syndrome (leukoderma)

Neoplastic Blepharitis

• •Meibomian gland adenoma
• •Papillomas
• •Squamous cell carcinoma
• •Lymphosarcoma
• •Mast cell tumor

Miscellaneous Eyelid Diseases

• •Juvenile sterile granulomatous dermatitis and lymphadenitis/juvenile cellulitis (puppy strangles)
• •Canine reactive histiocytosis
• • Entropion
• •Ectropion
• •Distichiasis
• •Trichiasis

Nonhealing Corneal Erosions (Ulcers) in Dogs

Causes

Establish underlying cause of impaired wound healing.

• •Mechanical trauma from lid masses
• •Entropion
• •Foreign bodies
• •Secondary infection
• •Corneal exposure caused by lid paralysis
• •Exophthalmos
• •Buphthalmos
• •Tear film abnormalities
• •Conformational abnormalities resulting in lagophthalmos
• •Corneal edema
• •Distichiasis
• •Facial fold irritation of cornea

Spontaneous Chronic Corneal Epithelial Defects (SCCEDs)—also called indolent erosions/ulcers or boxer erosions/ulcers

• •Middle-aged dogs
• •Boxers predisposed
• •Likely instigated by superficial trauma
• •Dogs with diabetes mellitus predisposed
• •Rim of loose epithelium surrounds corneal defect
• •No loss of stromal substance (stromal loss indicates more severe process, typically infection)
• •Blepharospasm/epiphora
• •Neovascularization may be delayed compared with healing corneal ulcers.

Bullous Keratopathy

 

Ocular Manifestations of Systemic Diseases

Surface Ocular Disease

Eyelids

• Immunosuppressive disorders may predispose to meibomian gland infection with Demodex or Staphylococcus spp.

• Eyelids have mucocutaneous junction; affected by autoimmune disorders such as systemic lupus erythematosus (SLE) and pemphigoid diseases; also may be affected by uveodermatologic syndrome and vasculitis

• Altered lid position, cranial nerve III or VII dysfunction

• Horner syndrome: decreased sympathetic tone causing enophthalmos with third eyelid protrusion, ptosis, and miosis; often idiopathic; may be seen with disease of brain, spinal cord, brachial plexus, thorax, mediastinum, neck, temporal bone, tympanic bulla, or orbit

Conjunctivitis

• May reflect disease of deeper ocular structures

• Good location to detect pallor, cyanosis, icterus

• Feline herpesvirus type 1 (FHV-1) and Chlamydophila felis are primary pathogens of the conjunctiva.

Cornea/Sclera

• Creamy pink discoloration of cornea may be seen with lymphoma.

• Corneal lipidosis appears similar; it may be secondary to hyperlipidemia from hypothyroidism, hyperadrenocorticism, diabetes mellitus, and familial hypertriglyceridemia.

Keratoconjunctivitis Sicca

• Most cases are caused by lymphoplasmacytic dacryoadenitis.

• Rarely seen with xerostomia (Sjögren-like syndrome)

• Possible causes include drug therapy, atropine, sulfa drugs, etodolac, and anesthetic agents.

• Others causes include canine distemper, FHV-1, and dysautonomia.

Uveal Tract, Lens, Fundus

Uveal Tract

Hyphema or Hemorrhage

• Hypertension, rickettsial disease, trauma, coagulopathy, lymphoma, metastatic neoplasia

Protein or Fibrin Deposition

• Trauma, feline infectious peritonitis (FIP), uveodermatologic syndrome, lens capsule rupture, rickettsial disease

Cellular (Hypopyon) or Granulomatous Infiltrates

• Trauma, lymphoma, metastatic neoplasia, uveodermatologic syndrome, algae or yeast, lens capsule rupture, FIP, systemic mycoses, toxoplasmosis

• Other infectious agents associated with uveal tract disease include feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), mycobacteria, FHV-1, Bartonella spp., Ehrlichia spp., Leishmania donovani, Rickettsia rickettsii, Brucella canis, Leptospira spp., and canine adenovirus.

Iris Abnormalities (Papillary Changes)

• Anisocoria with FeLV

• Miosis with Horner syndrome

• Mydriasis with dysautonomia

Lens

Cataracts

• Most common cause in dogs is hereditary.

• Cataracts are frequent complication of diabetes mellitus.

• Uveitis may also cause cataracts (most common cause in cats).

• Other causes include hypocalcemia (hypoparathyroidism), electric shock, lightning strike, altered nutrition (e.g., puppies fed milk replacer).

Lens Luxation/Subluxation

• Most often secondary to severe intraocular disease (uveitis)

• May be primary in terriers

Fundus

• Usually affected by diseases that extend from the uveal tract (see previous section) or from central nervous system (immune-mediated diseases such as granulomatous meningoencephalitis or neoplasia of CNS).

Papilledema

• Optic nerve edema without hemorrhage, exudates, or blindness

• Seen with increased intracranial pressure

Taurine Deficiency

• Retinal degeneration

• May also cause dilated cardiomyopathy

Retinal Visualization

• Allows assessment of systemic condition including anemia (attenuated, pale vessels), hyperlipidemia (creamy orange hue to vessels), hyperviscosity (increased vessel tortuosity)

Systemic Hypertension

• Causes extravasation of blood into retina, choroid, or subretinal space

Ocular Neoplasia

Orbital Neoplasia (presents as exophthalmos, strabismus, protrusion of the third eyelid, epiphora, and exposure keratitis)

• •Osteosarcoma
• •Multilobular osteosarcoma
• •Fibrosarcoma
• •Invasion of orbit by neoplasms of surrounding structures such as nose, sinuses, oral cavity, and orbital glands (nasal adenocarcinoma most commonly)
• •Cats are more likely to have invasion of orbit from surrounding structures (fibrosarcoma, undifferentiated sarcoma, adenocarcinoma, lymphoma). Rarely see primary orbital neoplasia (squamous cell carcinoma, melanoma)

Adnexal Neoplasia (eyelid neoplasia common in dogs and rare in cats)

• •90% of eyelid tumors are benign (meibomian adenomas, melanomas, papillomas most commonly).
• •Less common adnexal tumors include histiocytoma, malignant melanoma, adenocarcinoma, basal cell carcinoma, mast cell tumor, squamous cell carcinoma, hemangiosarcoma.
• •Squamous cell carcinoma is the most common eyelid tumor in cats. Associated with sun exposure in cats that lack periocular pigmentation.

Surface Ocular Neoplasia (tumors of the conjunctiva, third eyelid, cornea)

• •Dermoid
• •Epibulbar or limbal melanocytoma
• •Conjunctival neoplasia: hemangioma, hemangiosarcoma, mast cell tumor, lymphoma, squamous cell carcinoma, papilloma
• •Third eyelid neoplasia: adenocarcinoma (most common), hemangiosarcoma, lobular adenoma, squamous cell carcinoma, melanoma

Intraocular Neoplasia (present with glaucoma, hyphema, corneal edema, buphthalmos, dyscoria, uveitis, retinal detachment, blindness)

• •Anterior uveal melanoma (most common), 82% are benign in dogs, poorer prognosis in cats
• •Other primary tumors of dogs include ciliary body adenocarcinoma and medulloepithelioma.
• •Other primary tumors of cats include posttraumatic sarcoma and lymphoma.

Red Eye

Differential Diagnosis

Erythema of Primarily Conjunctival Vessels

• •Corneal ulceration
• •Eyelid abnormalities
• •Dacryocystitis
• •Cilia abnormalities
• •Keratoconjunctivitis sicca
• •Allergic conjunctivitis
• •Bacterial or fungal keratitis
• •Orbital disease

Erythema of Primarily Episcleral Vessels

• •Anterior uveitis (low intraocular pressure)
• •Glaucoma (high intraocular pressure)

Focal Erythema

Masses

• •Prolapse of the gland of the third eyelid
• •Neoplasia
• •Episcleritis
• •Nodular granulomatous episcleritis
• •Granulation tissue

Hemorrhage

• •Trauma
• •Systemic disease (vasculitis, coagulopathy)

Retinal Detachment

Differential Diagnosis

Three Main Mechanisms—exudative, associated with retinal tears (rhegmatogenous), or traction pulling on retina

• •Trauma—penetrating injuries such as animal bites, projectiles, or foreign bodies may result in retinal tears or induce intraocular hemorrhage, inflammation, or vitreous infection with subsequent traction retinal detachment. Typically unilateral, although strangulation can lead to bilateral retinal detachment
• •Ocular anomalies such as severe retinal dysplasia, optic nerve colobomas, vitreous abnormalities, and retinal nonattachment (developmental failure of the two retinal layers to unite)
• •Later-onset ocular anomalies such as cataracts and vitreous degeneration may lead to rhegmatogenous RD, especially with rapid-forming or hypermature cataracts that lead to lens-induced uveitis.
• •Hypertension is most often related to renal disease but may also be seen with hyperthyroidism and pheochromocytoma.
• •Hyperviscosity—severe hyperlipidemia, hyperglobulinemia, polycythemia
• •Neoplasia—most commonly due to multiple myeloma (hyperproteinemia and hyperviscosity) and lymphoma (infiltration of retina and choroid). Large intraocular tumors may induce traction retinal detachment.
• •
  Chorioretinitis, retinochoroiditis

  • •
    Bacteria (leptospirosis, brucellosis, bartonellosis
  • •
    Rickettsia (ehrlichiosis, Rocky Mountain spotted fever)
  • •
    Fungal (aspergillosis, blastomycosis, coccidioidomycosis, histoplasmosis, cryptococcosis)
  • •
    Algae (geotrichosis, protothecosis)
  • •
    Viral (canine distemper virus, FIP)
  • •
    Secondary to retroviral infection (FeLV, FIV by predisposing to lymphosarcoma or an opportunistic infection like toxoplasmosis)
  • •
    Parasitic (causes smaller areas of detachment—larval migrans of strongyles, ascarids, or Baylisascaris larvae. Toxoplasmosis, leishmaniasis, neospora, babesiosis.
• •
  Immune-mediated disease—causes vasculitis with or without chorioretinitis

  • •
    Systemic lupus erythematosus
  • •
    Uveodermatologic syndrome
  • •
    Granulomatous meningoencephalitis
• •Toxic—trimethoprim/sulfa or ethylene glycol in dogs, griseofulvin in cats
• •Idiopathic

Uveitis

Differential Diagnosis in the Dog(d) and Cat(c)

Systemic Infection

Bacterial

• •Bacteremia or septicemia (d, c)
• •Bartonellosis (d, c)
• •Leptospirosis (d)
• •Borreliosis (d)
• •Brucellosis (d)

Rickettsial

• •Ehrlichiosis (d, c)
• •Rocky Mountain spotted fever (d)

Viral

• •Canine adenovirus-1 (d)
• •Feline leukemia virus (c)
• •Feline immunodeficiency virus (c)
• •Feline infectious peritonitis (c)

Mycotic

• •Blastomycosis (d, c)
• •Histoplasmosis (d, c)
• •Coccidiomycosis (d, c)
• •Cryptomycosis (d, c)
• •Aspergillosis (d)

Algal

• •Protothecosis

Parasitic

• •Aberrant nematode larval migration
• • Toxocara (ocular larval migrans) (d, c)
• • Dirofilaria larvae (d)

Protozoan

• •Toxoplasmosis (d, c)
• •Leishmaniasis (d, c)

Immune-Mediated uveitis

• •Idiopathic anterior uveitis (d, c)
• •Lens-induced uveitis (d, c)
• •Canine adenovirus vaccine reaction (d)
• •Uveodermatologic syndrome (d) (primarily Akita and Arctic breeds)
• •Pigmentary uveitis (d) (primarily Golden Retrievers)

Neoplasia

• •Primary (d, c)
• •Metastatic (most commonly lymphoma) (d, c)

Metabolic

• •Diabetes mellitus (lens-induced uveitis) (d)
• •Hyperlipidemia (d)

Trauma

• •Blunt or sharp (d, c)

Miscellaneous Causes of Blood/Eye Barrier Disruption

• •Hyperviscosity syndrome (d, c)
• •Hypertension (d, c)
• •Scleritis (d)
• •Ulcerative keratitis (d, c)

SECTION XIII. Toxicology

• Chemical Toxicoses

• Plant Toxicoses

• Venomous Bites and Stings

Chemical Toxicoses

Toxicants

Kerosene, Gasoline, Mineral Seal Oil, Turpentine, Others

• Pulmonary, central nervous system (CNS), and gastrointestinal (GI) signs: may lead to hepatotoxicity, renal toxicity, and cardiac arrhythmias

Naphthalene (Mothballs)

• Vomiting, lethargy, seizures, acute Heinz body hemolytic anemia, methemoglobinemia, hemoglobinuria, renal failure

Ethanol, Methanol (Wood Alcohol)

• CNS depression, behavioral changes, ataxia, hypothermia, respiratory and cardiac arrest

Ethylene Glycol

• Early intoxication: ataxia, progresses to oliguric renal failure with renomegaly, vomiting, hypothermia, coma, and death

Soaps and Detergents

• GI irritants

Household Corrosives

• Toilet bowl cleansers, calcium/lime/rust removers, drain cleaners, oven cleaners, bleaches

Propylene Glycol

• Ataxia, CNS depression

Phenol Products (Household Cleaners)

• Cats particularly sensitive; hepatic and renal damage, ataxia, weakness, tremors, coma, seizures, respiratory alkalosis

Anticoagulant Rodenticides

• Petechiae, ecchymosis, weakness, pallor, respiratory distress, CNS depression, hematemesis, epistaxis, melena, ataxia, paresis, seizures, sudden death

Zinc Phosphate

• Anorexia, lethargy, weakness, abdominal pain, vomiting early after ingestion, progresses to recumbency, tremors, seizures, cardiopulmonary collapse, death

Cholecalciferol (Vitamin D) Rodenticides and Medications

• Anorexia, CNS depression, vomiting, muscle weakness, constipation, bloody diarrhea, polyuria/polydipsia

Bromethalin Rodenticides

• High-dose exposure: muscle tremors, hyperexcitability, vocalization, seizures, hyperesthesia, vomiting, dyspnea

Pyrethrin and Pyrethroid Insecticides

• CNS depression, hypersalivation, muscle tremors, vomiting, ataxia, dyspnea, anorexia, hypothermia, hyperthermia, seizures, rarely death

Organophosphate and Carbamate Insecticides

• Muscarinic signs (salivation, lacrimation, bronchial secretion, vomiting, diarrhea) and nicotinic signs (muscle tremors, respiratory paralysis), mixed signs (CNS depression, seizures, miosis, hyperactivity)

2,4-Dichlorophenoxyacetic Acid

• Vomiting, diarrhea; greater exposure may cause CNS depression, ataxia, and hindlimb myotonia.

Lead (Paints, Batteries, Linoleum, Solder, Plumbing Supplies, Fishing Weights)

• High-level exposure: vomiting, abdominal pain, anorexia, diarrhea, megaesophagus

• CNS signs, behavioral changes, hysteria, ataxia, tremors, opisthotonos, blindness, seizures

Zinc

• Acute ingestion: vomiting, CNS depression, lethargy, diarrhea

• Chronic exposure: anorexia, vomiting, diarrhea, CNS depression, pica, hemolysis, regenerative anemia, spherocytosis, inflammatory leukogram, icterus, renal failure

Iron

• Vomiting, diarrhea, abdominal pain, hematemesis, melena; rarely, progresses to multisystemic failure

Plant Toxicoses

Plants That Cause Hemolysis

• Onion

Plants That Affect the Cardiovascular System

• Cardiac glycoside toxicity: bradycardia with first-, second-, or third-degree atrioventricular (AV) block, ventricular arrhythmias, asystole, and sudden death; also see gastrointestinal (GI) signs

  • Common oleander (Nerium oleander)
  • Yellow oleander (Thevetia peruviana)
  • Foxglove (Digitalis purpurea)
  • Lily of the valley (Convallaria majalis)
  • Kalanchoe (Bryophyllum spp.)

• Azalea (Rhododendron spp.): weakness, hypotension, dyspnea, respiratory failure, GI signs

• Yew (Taxus spp.): conduction disturbances, bradycardia, GI signs, weakness, seizures; poor prognosis once signs are seen

Plants Affecting the Gastrointestinal System

• Oxalate-containing plants: gastric and ocular irritants

• Dumbcane (Dieffenbachia spp.)

• Philodendron (Philodendron spp.)

• Peace lily (Spathiphyllum spp.)

• Devil's ivy (Epiprennum aureum)

• Rhubarb leaves (Rheum spp.)

• Philodendron may cause renal and central nervous system (CNS) signs in cats.

• Chinaberry tree (Melia azedarach): vomiting, diarrhea, abdominal pain, hypersalivation, may progress to CNS signs and death

• Cycad palms (Cycas spp.) or sago palms (Macrozamia spp.): vomiting, diarrhea, followed by lethargy, depression, liver failure, and death (dogs)

• English ivy (Hedera helix): GI irritation, profuse salivation, abdominal pain, vomiting, diarrhea

• Castor bean plant (Ricinus communis): ricin is among the most deadly poisons in the world; severe abdominal pain, vomiting, diarrhea, seizures, cerebral edema; prognosis for recovery is poor once clinical signs develop.

• Holly (Ilex spp.), poinsettia (Euphorbia pulcherrima), mistletoe (Phoradendron flavescens): mild GI irritation, occasionally diarrhea, more serious effects with mistletoe

• Amaryllis, jonquil, daffodil (family Amaryllidaceae), tulip (family Liliaceae), iris (family Iridaceae): ingestion of bulb associated with mild to moderate gastroenteritis

• Autumn crocus (Colchinum autumnale), glory lily (Gloriosa spp.): colchicine, vomiting, diarrhea, abdominal pain, hypersalivation progressing to depression, multiple organ system collapse and death

• Solanaceae family: tomato, eggplant, deadly or black nightshade, Jerusalem cherry-solanine, gastric irritant; may cause CNS depression and cardiac arrhythmias; nightshade can also contain belladonna.

• Mushrooms: amanitine poisoning (Amanita virosa, Amanita phalloides, Conocybe filaris), orellanine poisoning (Cortinarius orellanus, Cortinarius rainierensis), monomethylhydrazine (Gyromitra esculenta)—severe hepatic disease; survivors of hepatic phase may succumb to renal tubular necrosis.

Plants Affecting the Neurologic System

• Tobacco (Nicotiana tabacum): vomiting, CNS involvement, cardiac involvement

• Hallucinogenic plants: psilocybins or “magic mushrooms,” marijuana (Cannabis sativa), jimsonweed (Datura stramonium), thorn apple (Datura metaliodyl), blue morning glory (Ipomoea violacea), nutmeg (Myristica fragrans), peyote (family Cactaceae)

• Nettle toxicity (family Urticaceae): hunting dogs, toxins contained in needles (histamine, acetylcholine, serotonin, formic acid), salivation, vomiting, pawing at mouth, tremors, dyspnea, slow and irregular heartbeat

• Macadamia nuts: locomotor disturbances, tremors, ataxia, weakness

• Yesterday, today, tomorrow (Brunfelsia spp.)

Plants Affecting the Renal System

• Easter lily (Lilium longiflorum) and daylily (Hemerocallis spp.), possibly other lilies: toxic to cats, vomiting, depression, anorexia, leading to acute renal failure, poor prognosis without early treatment

• Raisins/grapes: acute renal failure

Plants Causing Sudden Death

• Seeds of many fruit trees (apple, apricot, cherry, peach, plum), contain cyanogenic glycosides

Venomous Bites and Stings

Snakes, Spiders, Others

Crotalids (Pit Vipers, Rattlesnakes, Copperheads, Water Moccasins)

• Enzymatic and nonenzymatic proteins, local tissue damage: localized pain, salivation, weakness, fasciculations, hypotension, alterations in respiratory pattern, regional lymphadenopathy, mucosal bleeding, obtundation, convulsions, anemia, echinocytosis, stress leukogram

Elapids (Coral Snakes)

• Rare envenomation, signs delayed 10–18 hours, emesis, salivation, agitation, central depression, quadriplegia, hyporeflexia, intravascular hemolysis, respiratory paralysis

Latrodectus spp. (Widow Spiders)

• Hyperesthesia, muscle fasciculations, cramping, somatic abdominal pain (characteristic sign), respiratory compromise, hypertension, tachycardia, seizures, agitation, ataxia, cardiopulmonary collapse

Loxoscelidae (Recluse or Brown Spiders)

• Cutaneous form: bull's-eye lesion, pale center with localized thrombosis, surrounded by erythema, develops into a hemorrhagic bulla with underlying eschar

• Viscerocutaneous form: Coombs-negative hemolytic anemia, thrombocytopenia, disseminated intravascular coagulation (DIC)

Tick Paralysis

• Dermacentor and Haemaphysalis ticks, ascending paralysis, lower motor neuron signs, megaesophagus and aspiration pneumonia in severe cases, spontaneous recovery a few days after tick removal

Hymenopteran Stings

• Bites and stings of winged insects and fire ants

• Toxic and allergic reactions (localized angioedema, urticaria, emesis, diarrhea, hematochezia, respiratory depression, death)

Helodermatidae Lizard (Gila Monster)

• Salivation, lacrimation, emesis, tachypnea, respiratory distress, tachycardia, hypotension, shock

SECTION XIV. Urogenital Disorders

• Differentiating between Urine Marking and Inappropriate Elimination in Cats

• Glomerular Disease

• Indications for Cystoscopy

• Mammary Masses

• Prostatic Disease

• Proteinuria in Dogs and Cats

• Pyelonephritis, Bacterial

• Renal Disease

• Reproductive Disorders

• Ureteral Diseases

• Urinary Tract Infection (UTI)

• Uroliths, Canine

• Vaginal Discharge

Differentiating between Urine Marking and Inappropriate Elimination in Cats

Urine Marking

• •Generally vertical surfaces (can be horizontal)
• •Marking behavior (may be territorial signaling or an anxiety- or conflict-induced response)
• •Most common in intact males, females in estrous
• •Adults
• •Urine (rarely stool)
• •Doors, windows, new objects, owner's possessions, frequently used furniture

Inappropriate Elimination

• •Horizontal surfaces (rarely vertical)
• •Elimination behavior
• •Males or females, intact or neutered
• •Any age
• •Urine and/or stool
• •Elimination in a variety of areas

Glomerular Disease

Types, Dogs and Cats

• Glomerulonephritis

  • Membranoproliferative form

    • •
      Type I (mesangiocapillary)
    • •
      Type II (dense deposit disease)
  • Proliferative glomerulonephritis (mesangial and endocapillary)
  • Crescentic type (rare)

• Amyloidosis

• Glomerulosclerosis

• Focal segmental glomerulosclerosis

• Hereditary nephritis

• Immunoglobulin A (IgA) nephropathy

• Lupus nephritis

• Membranous glomerulopathy (most common in cats)

• Minimal change glomerulopathy

Differential Diagnosis for Diseases Associated with Glomerular Disease, Dogs

Infection

Bacterial

• Pyelonephritis

• Pyoderma

• Pyometra

• Endocarditis

• Bartonellosis

• Brucellosis

• Borreliosis

• Other chronic bacterial infections

Parasitic

• Dirofilariasis

Rickettsial

• Ehrlichiosis

Fungal

• Blastomycosis

• Coccidioidomycosis

Protozoal

• Babesiosis

• Hepatozoonosis

• Leishmaniasis

• Trypanosomiasis

Viral

• Canine adenovirus (type I) infection

Inflammation

• Periodontal disease

• Chronic dermatitis

• Pancreatitis

• Inflammatory bowel disease

• Polyarthritis

• Systemic lupus erythematosus (SLE)

• Other immune-mediated diseases

Neoplasia

• Lymphosarcoma

• Mastocytosis

• Leukemia

• Systemic histiocytosis

• Primary erythrocytosis

• Other neoplasms

Miscellaneous

• Corticosteroid excess

• Trimethoprim-sulfa therapy

• Hyperlipidemia

• Chronic insulin infusion

• Congenital C3 deficiency

• Cyclic hematopoiesis in gray Collies

Familial

• Amyloidosis (Beagle, English Foxhound)

• Hereditary nephritis (Bull Terrier, English Cocker Spaniel, Dalmatian, Samoyed)

• Glomerulosclerosis (Doberman Pinscher, Newfoundland)

• Glomerular vasculopathy and necrosis (Greyhound)

• Mesangiocapillary glomerulonephritis (Bernese Mountain Dog)

• Atrophic glomerulopathy (Rottweiler)

• Proliferative and sclerosing glomerulonephritis (Soft-Coated Wheaten Terrier)

Idiopathic

 

Differential Diagnosis for Diseases Associated with Glomerular Disease, Cats

Infection

Bacterial

• Pyelonephritis

• Chronic bacterial infections

• Mycoplasmal polyarthritis

Viral

• Feline immunodeficiency virus (FIV)

• Feline infectious peritonitis (FIP)

• Feline leukemia virus (FeLV)

Inflammation

• Pancreatitis

• Cholangiohepatitis

• Chronic progressive polyarthritis

• SLE

• Other immune-mediated diseases

Neoplasia

• Lymphosarcoma

• Leukemia

• Mastocytosis

• Other neoplasms

Miscellaneous

• Acromegaly

• Mercury toxicity

Familial

 

Idiopathic

 

Indications for Cystoscopy

• •Localization of source of hematuria
• •
  Urinary tract neoplasia

  • •
    Determine extent and location of tumors
  • •
    Obtain samples for cytology or histopathology
• •
  Recurrent urinary tract infections

  • •
    Examine for anatomic abnormalities or uroliths
  • •
    Obtain samples for cytology, histopathology, or culture
• •
  Urinary tract trauma

  • •
    Examine for perforations, ruptures, and patency of urinary tract
• •
  Urinary incontinence

  • •
    Examine for ectopic ureters and/or urethral anomalies
  • •
    Laser ablation of intramural ectopic ureters
  • •
    Periurethral collagen injections for treatment of refractory urethral incompetence
• •
  Urolithiasis

  • •
    Confirm and remove small uroliths from bladder or urethra
  • •
    Obtain uroliths for quantitative analysis and culture
  • •
    Retrieve uroliths from bladder or urethra using stone forceps or stone basket
  • •
    Fragment uroliths with laser lithotripsy
  • •
    Fill bladder before and after voiding urohydropropulsion to remove small uroliths

Mammary Masses

Differential Diagnosis

• •
  Benign mammary tumors

  • •
    Mixed tumors (fibroadenomas)
  • •
    Adenomas
  • •
    Mesenchymal tumors
• •
  Malignant mammary tumors

  • •
    Solid carcinomas
  • •
    Tubular adenocarcinomas
  • •
    Papillary adenocarcinomas
  • •
    Anaplastic carcinomas
  • •
    Sarcomas (rare)
  • •
    Most feline mammary tumors are adenocarcinomas
• •Mammary hyperplasia
• •Mastitis
• •Granulomas
• •Duct ectasia
• •Skin tumors
• •Lipomas
• •Foreign bodies (e.g., BB pellets or shot may be confused with small mammary masses)

Prostatic Disease

Differential Diagnosis

• Benign prostatic hyperplasia

• Acute prostatitis

• Chronic prostatitis

• Abscess

• Cyst

• Prostatic neoplasia

  • •
    Adenocarcinoma most common
  • •
    Transitional cell carcinoma second most common
  • •
    Sarcomatoid carcinoma
  • •
    Primary and metastatic hemangiosarcoma
  • •
    Lymphoma

Diagnostic Evaluation

• •History of lower urinary tract signs, penile discharge, hematuria, dysuria, tenesmus, obstipation, ribbon stools, stiff gait. Severe systemic signs suggest sepsis or systemic inflammation raises suspicion of acute prostatitis. Intact males are more predisposed to BPH and prostatitis.
• •Digital rectal examination along with caudal abdominal palpation is a noninvasive initial screening test. The rectum should be bilaterally symmetric, have a smooth and regular surface, have soft parenchyma, and not be painful to touch.
• •Radiography of limited value for providing an actual diagnosis but may provide information about size, shape, contour, and location of the prostate. Prostatomegaly may cause dorsal displacement of the colon and cranial displacement of the urinary bladder. Mineralization with neoplasia, bacterial prostatitis, and abscessation may be apparent.
• •Prostatic ultrasound is the most useful and practical imaging method. Normal prostate should have smooth borders and homogenous parenchymal pattern of moderate echogenicity. Ultrasound also offers the opportunity for guided aspirates and core biopsy sampling for culture, cytology, and histopathology.
• •CT and MRI can evaluate size, shape, homogeneity of prostate and allow evaluation of intrapelvic lesions, metastatic spread, and ureteral obstruction.
• •Definitive diagnosis requires cytologic, histologic, or bacteriologic evaluation of a prostate sample. Samples can be obtained using procedures such as semen collection, prostatic massage and wash, brush technique, fine needle aspiration, and biopsy.

Proteinuria in Dogs and Cats

Diagnostic Approach

• •Stop use of nephrotoxic drugs.
• •If proteinuria is insignificant (trace to 1+ dipstick reading and urine specific gravity > 1.035), there is no need for further workup.
• •Perform urinalysis to exclude hemorrhage, infection, or inflammation as cause of proteinuria. If these conditions present, do urine culture. If these conditions are not present, do urine protein/creatinine ratio.
• •
  Perform serum chemistry and CBC. Evaluate serum albumin and globulin.

  • •
    Marked proteinuria ratio (UP/UC > 3) with quiet sediment and normal globulins or a polyclonal gammopathy is consistent with renal glomerular disease (glomerulonephritis, amyloidosis). Rule out causes of glomerulonephropathy such as heartworm disease, hepatozoonosis, immune-mediated diseases such as SLE, chronic infectious diseases such as borreliosis, feline leukemia virus, feline immunodeficiency virus, ehrlichiosis, other chronic inflammatory diseases, neoplasia, and hyperadrenocorticism).
  • •
    If no underlying disease found, may need renal biopsy to assess for glomerulonephritis or amyloidosis
• •Proteinuria detected by precipitation testing but not dipstick or proteinuria associated with a monoclonal gammopathy may be caused by Bence Jones proteins. This requires a search for osteolytic or lymphoproliferative lesions. Ehrlichiosis may mimic myeloma. If Ehrlichia negative, protein electrophoresis in indicated. A monoclonal gammopathy suggests myeloma.

Pyelonephritis, Bacterial

Clinical Findings, Dogs and Cats

• Fever

• Renal pain

• Leukocytosis

• Anorexia

• Lethargy

• Cellular casts in urine sediment

• Azotemia

• Inability to concentrate urine

• Polyuria/polydipsia

• Ultrasonographic or excretory urographic abnormalities

  • •
    Renal pelvis dilatation
  • •
    Asymmetric filling of diverticula
  • •
    Dilated ureters

• Bacteria in inflammatory lesions on histopathologic examination

• Positive culture of ureteral urine collected by cystoscopy

• Positive culture of urine obtained after rinsing bladder with sterile saline

• Positive culture of urine obtained by ultrasound-guided pyelocentesis

Renal Disease

• See Glomerular Disease.

Familial—Dogs And Cats

• Amyloidosis—Beagle, English Foxhound, Shar-Pei, Abyssinian cat, Oriental shorthaired cat, Siamese cat

• Renal Dysplasia—Lhasa Apso, Shih Tzu, Standard Poodle, Soft Coated Wheaten Terrier, Chow Chow, Alaskan Malamute, Miniature Schnauzer, Dutch Kooiker (Dutch decoy dog)

• Fanconi syndrome (tubular dysfunction)—Basenji

• Tubular dysfunction (renal glucosuria)—Norwegian Elkhound

• Basement membrane disorder—Bull Terrier, Doberman Pinscher, English Cocker Spaniel, Samoyed

• Membranoproliferative glomerulonephritis—Bernese Mountain Dog, Brittany Spaniel, Soft-Coated Wheaten Terrier

• Primary glomerular disease—Rottweiler, Beagle, Pembroke Welsh Corgi, Newfoundland, Bullmastiff, Doberman Pinscher, Dalmatian, Bull Terrier, English Cocker Spaniel, Samoyed

• Periglomerular fibrosis—Norwegian Elkhound

• Polycystic kidney disease—Cairn Terrier, West Highland White Terrier, Bull Terrier, Persian cat

• Multifocal cystadenocarcinoma—German Shepherd

Differential Diagnosis, Renal Tubular Disease

Cystinuria

• Inherited proximal tubular defect

• Many breeds of dogs including mixed breeds

• Often leads to cystine calculi formation

Carnitinuria

• Reported in dogs with cystinuria

• May lead to carnitine deficiency and cardiomyopathy

Hyperuricosuria

• Abnormal purine metabolism

  • •
    Dalmatian
  • •
    Dogs with primary hepatic disease

• May lead to urate urolithiasis

Hyperxanthinuria (rare)

• Seen in dogs receiving allopurinol to prevent urate uroliths

• Congenital hyperxanthinuria seen in a family of Cavalier King Charles Spaniels

Renal Glucosuria

• Primary renal glucouria (rare)

  • •
    Scottish Terrier, Basenji, Norwegian Elkhound, mixed breeds

Fanconi Syndrome

• Inherited proximal tubular defect

• Basenji most common

• May lead to renal failure

Renal Tubular Acidosis

• Rare tubular disorders that lead to hyperchloremic metabolic acidosis

  • •
    Proximal renal tubular acidosis
  • •
    Distal renal tubular acidosis

Nephrogenic Diabetes Insipidus

• Any renal disorder that suppresses the kidneys’ response to antidiuretic hormone (ADH)

• Congenital (rare)

• Acquired

  • •
    Toxic (Escherichia coli endotoxin)
  • •
    Drugs (glucocorticoids, chemotherapeutics)
  • •
    Metabolic disease (hypokalemia, hypercalcemia)
  • •
    Tubular injury or loss (polycystic renal disease, bacterial pyelonephritis)
  • •
    Medullary washout

Differentiating Acute from Chronic Renal Failure

Acute Renal Failure

• •History of ischemia
• •History of exposure to toxin
• •Active urine sediment
• •Good body condition
• •Hyperkalemia (if oliguric)
• •Normal to increased hematocrit
• •Enlarged kidneys
• •Potentially severe metabolic acidosis
• •Severe clinical signs for level of dysfunction

Chronic Renal Failure

• •History of previous renal disease
• •History of polyuria/polydipsia
• •Small irregular kidneys
• •Nonregenerative anemia
• •Normal to hypokalemia
• •Normal to mild metabolic acidosis
• •Inactive urine sediment
• •Weight loss/cachexia
• •Mild clinical signs for level of dysfunction

Renal Toxins in Dogs and Cats

Therapeutic Agents

Antibacterial Agents

• Aminoglycosides

• Sulfonamides

• Nafcillin

• Penicillins

• Cephalosporins

• Fluoroquinolones

• Carbapenems

• Rifampin

• Tetracyclines

• Vancomycin

Antifungal Agents

• Amphotericin B

Antiviral Agents

• Acyclovir

• Foscarnet

Antiprotozoal Agents

• Pentamidine

• Sulfadiazine

• Trimethoprim-sulfamethoxazole

• Dapsone

Anthelmintics

• Thiacetarsamide

Cancer Chemotherapeutics

• Cisplatin/carboplatin

• Methotrexate

• Doxorubicin

• Azathioprine

Immunosuppressive Drugs

• Cyclosporine

• Interleukin-2

Nonsteroidal Antiinflammatory Drugs (NSAIDs)

 

Angiotensin-Converting Enzyme (ACE) Inhibitors

 

Diuretics

 

Miscellaneous Agents

• Dextran 40

• Allopurinol

• Cimetidine

• Apomorphine

• Deferoxamine

• Streptokinase

• Methoxyflurane

• Penicillamine

• Acetaminophen

• Tricyclic antidepressants

Radiocontrast Agents

 

Nontherapeutic Agents

Heavy Metals

• Lead

• Mercury

• Cadmium

• Chromium

Organic Compounds

• Ethylene glycol

• Carbon tetrachloride

• Chloroform

• Pesticides

• Herbicides

• Solvents

Miscellaneous Agents

• Mushrooms

• Snake venom

• Grapes/raisins

• Bee venom

• Lily

Pigments

• Hemoglobin/myoglobin

Hypercalcemia

 

Causes of Acute Renal Failure in Dogs and Cats

Primary Renal Disease

Infection

• Pyelonephritis

• Leptospirosis

• Infectious canine hepatitis

Immune-Mediated Disease

• Acute glomerulonephritis

• Systemic lupus erythematosus (SLE)

• Renal transplant rejection

Renal Neoplasia

• Lymphoma

Nephrotoxicity

• Exogenous toxins

• Endogenous toxins

• Drugs

Renal Ischemia

Prerenal Azotemia

• Dehydration/hypovolemia

• Deep anesthesia

• Sepsis

• Shock/vasodilation

• Decreased oncotic pressure

• Hyperthermia

• Hypothermia

• Hemorrhage

• Burns

• Transfusion reaction

Renal Vascular Disease

• Avulsion

• Thrombosis

• Stenosis

Systemic Diseases with Renal Manifestations

• Infection

  • •
    Bacterial endocarditis
  • •
    Feline infectious peritonitis (FIP)
  • •
    Borreliosis
  • •
    Babesiosis
  • •
    Leishmaniasis

• Pancreatitis

• Diabetes mellitus

• Hyperadrenocorticism

• Hypoadrenocorticism

• Hypocalcemia

• Hypokalemia

• Hypomagnesemia

• Hyponatremia

• Systemic inflammatory response syndrome (SIRS)

• Sepsis

• Multiple organ failure

• Disseminated intravascular coagulation (DIC)

• Heart failure

• SLE

• Hepatorenal syndrome

• Malignant hypertension

• Hyperviscosity syndrome

  • •
    Polycythemia
  • •
    Multiple myeloma

• Urinary outflow obstruction

• Envenomation

Causes of Chronic Renal Failure in Dogs and Cats

• Inflammatory/infectious

  • •
    Pyelonephritis
  • •
    Leptospirosis
  • •
    Blastomycosis
  • •
    Leishmaniasis
  • •
    FIP

• Familial/congenital (see p. 265)

• Amyloidosis

• Neoplasia

  • •
    Lymphosarcoma
  • •
    Renal cell carcinoma
  • •
    Nephroblastoma
  • •
    Tumor lysis syndrome
  • •
    Others

• Nephrotoxicants (see p. 267)

• Renal ischemia

• Sequela of acute renal failure

• Glomerulopathies (see p. 259)

• Nephrolithiasis

• Bilateral hydronephrosis

  • •
    Spay granulomas
  • •
    Transitional cell carcinoma at trigone obstructing both ureters
  • •
    Nephrolithiasis

• Polycystic kidney disease

• Urinary outflow obstruction

• Idiopathic

Reproductive Disorders

Infertility—Differential Diagnosis, Canine Female

Normal Cycles

• Improper breeding management

• Failure to determine optimal breeding time

• Female behavior

• Infertile male

• Elevated diestrual progesterone

  • •
    Early embryonic death
  • •
    Lesions in tubular system (vagina, uterus, uterine tubes)
  • •
    Placental lesions (brucellosis, herpes)
• Normal diestrual progesterone

  • •
    Cystic follicles (ovulation failure)

Abnormal Cycles

Abnormal Estrus

Will Not Copulate

• Not in estrus

• Inexperience

• Partner preference

• Vaginal anomaly

• Hypothyroidism (possibly)

Prolonged Estrus

• Cystic follicles

• Ovarian neoplasia

• Exogenous estrogens

• Prolonged proestrus

Short Estrus

• Observation error

• Geriatric

• Ovulation failure

• Split estrus

Abnormal Interestrual Interval

Prolonged Interval

• Photoperiod (queen)

• Pseudopregnant/pregnant (queen)

• Normal breed variation

• Glucocorticoids (bitch)

• Old age

• Luteal cysts

Short Interval

• Normal (especially queen)

• Ovulation failure (especially queen)

• Corpus luteum failure

• “Split heat” (bitch)

• Exogenous drugs

Not Cycling

• Prepubertal

• Ovariohysterectomy

• Estrus suppressants

• Silent heat

• Unobserved heat

• Photoperiod (queen)

• Intersex (bitch)

• Ovarian dysgenesis

• Hypothyroidism (possibly)

• Glucocorticoid excess

• Hypothalamic-pituitary disorder

• Geriatric

Infertility—Differential Diagnosis, Canine Male

Inflammatory Ejaculate

• Prostatitis

• Orchitis

• Epididymitis

Azoospermia

• Sperm-rich fraction not collected

• Sperm not ejaculated

  • •
    Incomplete ejaculation
  • •
    Obstruction
  • •
    Prostate swelling
• Sperm not produced

  • •
    Endocrine
  • •
    Testicular
  • •
    Metabolic disorders

Abnormal Motility/Abnormal Morphology

• Iatrogenic

• Prepubertal

• Poor ejaculation

• Long abstinence

Abnormal Libido

• Female not in estrus

• Behavioral

• Pain

• Geriatric

Normal Libido

• Improper stud management

• Infertile female

Normal Libido/Abnormal Mating Ability

• Orthopedic

• Neurologic

• Prostatic disease

• Penile problem

• Prepuce problem

Penis, Prepuce, and Testes Disorders—Differential Diagnosis

Acquired Penile Disorders

• Penile trauma

  • •
    Hematoma
  • •
    Laceration
  • •
    Fracture of os penis

• Priapism (abnormal, persistent erection)

• Neoplasia

• Vesicles

• Warts

• Ulcers

Congenital Penile Disorders

• Persistent penile frenulum

• Penile hypoplasia

• Hypospadias (defect in closure of urethra)

• Diphallia (duplication of penis)

Preputial Disorders

• Balanoposthitis

  • •
    Bacteria infection
  • •
    Blastomycosis
  • •
    Canine herpesvirus

• Phimosis

• Paraphimosis

Testicular Disorders

• Cryptorchidism

• Orchitis/epididymitis

  • •
    Mycoplasma spp.
  • •
    Brucella canis
  • •
    Blastomyces spp.
  • •
    Ehrlichia spp.
  • •
    Rocky Mountain spotted fever
  • •
    Feline infectious peritonitis (FIP)

• Testicular torsion

• Testicular neoplasia

  • •
    Sertoli cell tumor
  • •
    Leydig cell tumor
  • •
    Seminoma

Drugs and Metabolic Disorders Affecting Male Reproduction

• Glucocorticoids (hyperadrenocorticism, exogenous glucocorticoids)

• Decreased luteinizing hormone (LH), testosterone, sperm output, seminal volume, and libido; increased sperm abnormalities

• Estrogens, androgens, anabolic steroids

• Decreased LH, testosterone, and spermatogenesis

• Cimetidine

• Decreased testosterone, libido, and sperm count

• Spironolactone, anticholinergics, propranolol, digoxin, verapamil, thiazide diuretics, chlorpromazine, barbiturates, diazepam, phenytoin, primidone

• Decreased testosterone and libido

• Progestagens, ketoconazole

• Decreased testosterone

• Amphoterin B, many anticancer drugs

• Decreased spermatogenesis

• Diabetes mellitus

• Decreased libido and sperm count, abnormal semen

• Renal failure, stress

• Decreased libido and sperm count

Ureteral Diseases

Differential Diagnosis

Vesicoureteral Reflux

• Primary: 7–12 weeks old—intrinsic maldevelopment of ureterovesical junction, self-limiting

• Secondary to lower urinary tract obstruction, urinary tract infection, surgical damage, neurologic disease of bladder, ectopic ureters

Congenital Anomalies

• Ectopic ureters

• Ureterocele

• Ureter agenesis

• Ureter duplication

Acquired Ureteral Disease

• Ureteral trauma

  • •
    Blunt trauma
  • •
    Penetrating trauma
  • •
    Iatrogenic damage during surgery

• Inadvertent ligation and transection during ovariohysterectomy

• Urinoma (paraureteral pseudocyst)

• Ureteral obstruction

  • •
    Intraluminal (blood clot, calculus)
  • •
    Intramural (fibrosis, stricture, neoplasia)
  • •
    Extramural (retroperitoneal mass, bladder neoplasia, inadvertent ligature)
• Calculi (nephroliths or nephrolith fragments that have migrated into the ureter)

  • •
    Calcium oxalate (most common in cat)
  • •
    Struvite (both struvite and calcium oxalate are most common in dog)
• Neoplasia

  • •
    Transitional cell carcinoma
  • •
    Leiomyoma
  • •
    Leiomyosarcoma
  • •
    Sarcoma
  • •
    Mast cell tumor
  • •
    Fibroepithelial polyp
  • •
    Benign papilloma
  • •
    Metastatic neoplasia

Urinary Tract Infection (UTI)

Clinical Findings

Lower UTI

• Dysuria

• Pollakiuria

• Urge incontinence

• Gross hematuria at end of micturition

• Cloudy urine

• Foul odor to urine

• Small, painful, thickened bladder

• Palpable urocystoliths

• Pyuria

• Hematuria

• Proteinuria

• Bacteruria

• Normal CBC

Upper UTI

• Polyuria/polydipsia

• Signs of systemic illness or infection

• Possible renal failure

• Fever

• Abdominal pain

• Kidneys normal to enlarged

• Leukocytosis

• Pyuria

• Hematuria

• Proteinuria

• Bacteruria

• Cellular or granular casts

• Decreased urine specific gravity

Acute Prostatitis or Prostatic Abscess

• Urethral discharge independent of micturition

• Signs of systemic illness/infection

• Fever

• Painful prostate or abdomen

• Prostatomegaly/asymmetry

• Leukocytosis (±)

• Pyuria

• Hematuria

• Proteinuria

• Bacteruria

• Inflammatory prostatic cytology

Chronic Prostatitis

• Recurrent UTIs

• Urethral discharge independent of urination

• Possible dysuria

• Normal complete blood count (CBC)

• Pyuria

• Hematuria

• Proteinuria

• Bacteruria

• Prostatomegaly/asymmetry

Canine Lower Urinary Tract Disease—Differential Diagnosis

Urocystoliths

• Struvite (magnesium ammonium phosphate)

• Calcium oxalate

• Purine (urate/xanthine)

• Cystine

• Calcium phosphate

• Silica

• Compound uroliths

Urethral Obstruction

• Urethroliths (see Urocystoliths)

• Blood clots

• Urethral stricture

• Neoplasia

  • •
    Transitional cell carcinoma
  • •
    Prostatic adenocarcinoma
  • •
    Leiomyoma
  • •
    Leiomyosarcoma
  • •
    Prostatic adenocarcinoma
  • •
    Squamous cell carcinoma
  • •
    Myxosarcoma
  • •
    Lymphoma
  • •
    Mast cell tumor

• Proliferative urethritis

• Urinary bladder entrapment in perineal hernia

• Trauma

  • •
    Penile fracture

Urinary Tract Trauma

• Contusion (bladder or urethra)

• Urethral tears

• Rupture of bladder (blunt trauma, secondary to pelvic fracture, penetrating wound)

• Avulsion of bladder or urethra

• Penile fracture

Inflammation (Bladder or Urethra)

• Bacterial UTI

• Fungal UTI

• Polypoid cystitis

• Emphysematous cystitis

• Cyclophosphamide-induced cystitis

• Parasitic cystitis (Capillaria plica)

Feline Lower Urinary Tract Disease—Differential Diagnosis

• Feline idiopathic cystitis

• Urethral plug (obstructive feline idiopathic cystitis)

• Urolithiasis

  • •
    Struvite
  • •
    Calcium oxalate
  • •
    Urate
  • •
    Cystine

• Bacterial cystitis (less common in cats than in dogs)

• Stricture

• Neoplasia

Uroliths, Canine

Characteristics

Calcium Oxalate Monohydrate or Dihydrate

• Radiopaque

• Acidic to neutral pH

• Sharp projections or smooth uroliths; calcium oxalate dihydrate uroliths may be jackstone shaped

• Not associated with urinary tract infection

• Calcium oxalate dihydrate crystals: square envelope shape

• Calcium oxalate monohydrate crystals: dumbbell shaped

Struvite (Magnesium-Ammonium-Phosphate)

• Radiopaque

• Alkaline pH

• Smooth to speculated if single; smooth and pyramidal in shape if multiple

• Associated with infection with urease-producing bacteria (Staphylococcus, Proteus, Ureaplasma spp., Klebsiella, Corynebacterium)

• “Coffin lid”–shaped crystals

Urate/Xanthine

• Radiolucent to faintly radiopaque

• Acidic pH

• Smooth uroliths

• Not associated with infection

• Yellow-brown “thorn apple” (spherical) or amorphous crystals

Cystine

• Faintly to moderately radiopaque

• Acidic pH

• Smooth, round uroliths; staghorn-shaped uroliths if nephroliths present

• Not associated with infection

• Hexagonal-shaped crystals

Calcium Phosphate

• Radiopaque

• Alkaline to normal pH for hydroxyapatite, acidic for brushite

• Small, variably shaped uroliths for hydroxyapatite

• Smooth, round or pyramidal for brushite

• Not associated with infection

• Amorphous phosphate crystals or thin prisms (calcium phosphate)

Silica

• Radiopaque

• Acidic to neutral pH

• Jackstone-shaped uroliths

• Not associated with infection

• No crystals

Vaginal Discharge

Differential Diagnosis

Cornified Epithelial Cells

• Normal proestrus

• Normal estrus

• Contamination of skin or epithelium

• Ovarian remnant syndrome

• Abnormal source of estrogen

  • •
    Exogenous
  • •
    Ovarian follicular cyst
  • •
    Ovarian neoplasia

• Contamination of squamous epithelium

Mucus

• Normal late diestrus or late pregnancy

• Normal lochia

• Mucometra

• Androgenic stimulation

Neutrophils

Nonseptic (no microorganisms seen)

• Vaginitis

• Normal first day of diestrus

• Metritis or pyometra

Septic

• Vaginitis

• Metritis

• Pyometra

• Abortion

Peripheral Blood

• Subinvolution of placental sites

• Uterine or vaginal neoplasia

• Trauma to reproductive tract

• Uterine torsion

• Coagulopathies

Cellular Debris

• Normal lochia

• Abortion

SECTION XV. Pain Diagnosis

• Acute Pain Assessment

• Acute Pain Preemptive Scoring System (examples in each category)

• Chronic Pain Assessment

Acute Pain Assessment

• Subjective evaluation of pain in animals relies on observation and interpretation of animal behavior. Pain may be indicated by loss of normal behaviors or appearance of abnormal behaviors.

Dogs

• •Restless, agitated, delirious
• •Lethargic, withdrawn, dull, obtunded
• •May ignore environmental stimuli
• •Abnormal sleep-wake cycle, inability to sleep
• •May bite, lick, or chew painful area
• •Adopt abnormal body positions to cope with pain
• •Ears held back, eyes wide open with dilated pupils or closed with a dull appearance
• •Disuse or guarding of painful area
• •Vocalization (whimper, yelp, whine, groan, yowl)
• •May become more aggressive and resist handling or palpation or may become more timid and seek increased contact with caregivers

Cats

• •Hide, stay to back of cage
• •Behavior may be mistaken for fear or anxiety
• •May sit very quietly and pain may be missed by those looking for more active signs of pain
• •May continue to purr while in pain
• •May growl with ears flattened
• •May attempt escape
• •Lack of grooming
• •Hunched posture, statue-like appearance
• •Reduced or absent appetite
• •Tail flicking

Acute Pain Preemptive Scoring System (examples in each category)

Minor Procedures: No Pain

• •Physical examination, restraint
• •Radiography
• •Suture removal, cast application, bandage change
• •Grooming
• •Nail trim

Minor Surgeries: Minor Pain

• •Suturing, debridement
• •Urinary catheterization
• •Dental cleaning
• •Ear examination and cleaning
• •Abscess lancing
• •Removing cutaneous foreign bodies

Moderate Surgeries: Moderate Pain

• •Ovariohysterectomy, castration, caesarean section
• •Feline onychectomy
• •Cystotomy
• •Anal sacculectomy
• •Dental extraction
• •Cutaneous mass removal
• •Severe laceration repair

Major Surgeries: Severe Pain

• •Fracture repair, cruciate ligament repair
• •Thoracotomy, laminectomy, exploratory laparotomy
• •Limb amputation
• •Ear canal ablation

Chronic Pain Assessment

• •Clinical signs of chronic pain depend on underlying cause and pathologic state.
• •Range from subtle to obvious
• •May see acute flareups that require changes in treatment (e.g., osteoarthritic dog that experiences acute pain after excessive strenuous activity
• •Decreased activity
• •Reluctance to rise or play
• •Changes in sleep patterns
• •Changes in appetite
• •Changes in social interaction and grooming habits
• •Withdrawal, aggression
• •Owner observations are extremely important