Clinical Signs Approach to Differential Diagnosis

Abdominal Distension

Organomegaly

• Hepatomegaly (infiltrative, inflammatory, lipidosis, neoplasia)

• Splenomegaly (infiltrative, inflammatory, neoplasia, hematoma)

• Renomegaly (neoplasia, infiltrative)

• Miscellaneous neoplasia (gastrointestinal [GI] tract, ovaries, uterus, pancreas, prostate, adrenal glands)

• Generalized neoplasia (carcinomatosis, lymphosarcoma)

• Granuloma (pythiosis, aspergillosis)

• Pregnancy

• Prostatomegaly

Fluid

Contained in Organs

• Congestion resulting from splenic torsion or volvulus, or hepatic congestion from right-sided heart failure

• Cysts (paraprostatic, perinephric, hepatic)

• Hydronephrosis

• Distended urinary bladder

• Obstruction of intestines or stomach

• Ileus

• Pyometra

Free Fluid in Abdomen

• Transudate (portal hypertension, right-sided heart failure, hypoproteinemia secondary to protein-losing enteropathy, protein-losing nephropathy, or hepatic failure)

• Modified transudate (neoplasia, postsinusoidal portal hypertension, right-sided heart failure, heartworm-related caval syndrome, liver disease)

• Exudate (pancreatitis, feline infectious peritonitis [FIP], urine, bile, neoplasia, bowel perforation, foreign body)

• Chyle (trauma, neoplasia, infection, right-sided heart failure)

• Blood (coagulopathy, trauma, neoplasia)

Gas

Contained in Organs

• Gastric dilatation/volvulus

• Intestines secondary to obstruction

• Parenchymal organs infected with gas-producing bacteria (emphysematous gallbladder or urinary bladder)

Free in Abdomen

• Iatrogenic (after laparoscopy, laparotomy)

• Rupture of GI tract or uterus

Fat

• Obesity/lipoma

Weakened Abdominal Musculature

• Hyperadrenocorticism

Feces

• Obstipation/megacolon

Abdominal Effusions and Ascites

Transudate (< 1000 Cells, < 2.5 Total Solids, < 1.017 Specific Gravity)

Portal Hypertension

• Presinusoidal or sinusoidal liver disease

• Right-sided heart failure

Hypoalbuminemia (see Albumin p. 300)

• Liver failure

• Protein-losing enteropathy

Modified Transudate (> 1000 but < 10,000 Cells, 2.5-5.0 Total Solids, < 1.025 Specific Gravity)

Right-Sided Heart Failure

• Heartworm-related caval syndrome

• Liver disease

Exudate (> 5000 Cells, > 3.0 Total Solids, > 1.025 Specific Gravity)

Nonseptic

• Pancreatitis

• FIP

• Urine

• Bile

• Neoplasia (mesothelioma, lymphoma, carcinomatosis, any mass that causes lymphatic or vascular obstruction)

Septic

• Bowel perforation

• Foreign body

Chyle

• Trauma

• Neoplasia

• Infection

• Right-sided heart failure

Blood

• Coagulopathy

• Trauma

• Neoplasia (hemangiosarcoma, hepatocellular carcinoma)

• Iatrogenic (postsurgical)

Abdominal Pain, Acute

Gastrointestinal System

• Gastrointestinal ulceration

• Foreign body

• Gastric dilation/volvulus

• Gastroenteritis

• Obstipation

• Colitis

• Neoplasia

• Adhesions

• Intestinal ischemia

• Intestinal spasm

• Flatulence

Urogenital System

• Lower urinary tract infection

• Lower urinary tract obstruction

• Nonseptic cystitis (idiopathic cystitis—cats)

• Prostatitis/prostatic neoplasia

• Uroliths/renoliths/ureterolith

• Pyelonephritis

• Neoplasm

• Metritis

• Pyometra/uterine rupture

• Uterine torsion (rare)

• Testicular torsion

• Mastitis

• Dystocia

• Ovarian cyst

Spleen

• Rupture

• Neoplasm

• Infection

• Torsion

Peritoneum

• Peritonitis

  • •
    Septic
  • •
    Nonseptic (e.g., uroabdomen)

• Adhesions

• Mesenteric neoplasia, volvulus, inflammation

Hepatobiliary

• Hepatitis

• Hepatic abscess

• Hepatic trauma, rupture

• Hepatobiliary neoplasia

• Cholelithiasis or cholecystitis

• Cholangiohepatitis

Musculoskeletal

• Fractures

• Intervertebral disk disease

• Diskospondylitis

• Abscess

• Strangulated hernia

Miscellaneous

• Adrenalitis (associated with hypoadrenocorticism)

• Heavy metal intoxication

• Vasculopathy

  • •
    Rocky Mountain spotted fever
  • •
    Infarct

• Autonomic (abdominal) epilepsy

• Iatrogenic

  • •
    Misoprostol
  • •
    Bethanechol
  • •
    Postoperative pain

Aggressive Behavior

Cats

Pathophysiologic Causes of Feline Aggression

• Rabies

• Hyperthyroidism

• Seizures (epilepsy, central nervous system inflammation)

• Paradoxical effects of therapeutic drugs (e.g., benzodiazepines)

• Toxins (side effects)

• Cognitive dysfunction

• Brain neoplasia

Species-Typical Patterns of Feline Aggression Toward Humans

• Defensive response when threatened (may freeze, retreat, climb, or hide but aggression eventually becomes an option)

• Play/predatory/attention-seeking response

• Aggression as a response to frustration (also known as redirected aggression)

• Aggression that arises as a result of disease processes (see Pathophysiologic Causes of Feline Aggression earlier)

• Interspecies aggression (either fear induced or territorial/resource guarding)

Dogs

Pathophysiologic Causes of Canine Aggression

• Rabies

• Seizure activity

• Intracranial neoplasia

• Cerebral hypoxia

• Neuroendocrine disturbances

Species-Typical Patterns of Canine Aggression

• Fear related

• Conflict related

• Resource guarding

• Territorial/protective

• Intraspecific (intradog)

• Redirected

• Predatory

• Pain/medical/irritable

• Play

• Maternal/hormonal

• Idiopathic

Alopecia

Inflammatory Alopecia

Traumatic

• Allergy (flea, atopy, food)

• Parasitic dermatitis (flea, scabies, Cheyletiella spp., lice, chiggers, etc.)

Infectious

• Pyoderma

• Demodicosis

• Dermatophytosis

• Viral

• Leishmaniasis

• Malassezia spp.

Immune Mediated

• Sebaceous adenitis

• Superficial pemphigus

• Alopecia areata

• Erythema multiforme

• Systemic lupus erythematosus (SLE), discoid lupus erythematosus (DLE)

• Epitheliotropic lymphoma

• Vasculitis

Atrophic

• Dermatomyositis

• Cutaneous vasculitis

• Postvaccinal alopecia

• Lymphocytic mural folliculitis

• Paraneoplastic exfoliative dermatitis

• Pseudopelade

Noninflammatory Alopecia

Hormonal

• Hyperadrenocorticism

• Iatrogenic Cushing syndrome

• Hypothyroidism

• Sex hormone imbalance

• Alopecia X

• Hyperthyroidism (cat)

Canine Follicular Dysplasia

• Trichorrhexis nodosa

• Pili torti

• Color mutant alopecia

• Black hair follicular dysplasia

• Canine flank alopecia

• Anagen and telogen effluvium

Feline Congenital/Hereditary

• Alopecia universalis (Sphinx)

• Congenital hypotrichosis

• Hair shaft dysplasia (Abyssinian)

• Follicular dysplasia (Cornish Rex)

• Pili torti

Other

• Anagen effluvium

• Telogen defluxion

• Paraneoplastic alopecia

• Cyclic follicular dysplasia (seasonal flank alopecia)

• Postclipping alopecia

• Cicatricial alopecia

• Feline preauricular alopecia

• Feline acquired symmetric alopecia

• Psychogenic alopecia

Anaphylaxis

Venoms

• Insects of Hymenoptera order (bees, hornets, ants)

• Spiders (brown recluse, black widow)

• Snakes (rattlesnakes, copperheads, water moccasins)

• Lizards (Gila monster, Mexican beaded lizard)

Drugs

• Antibiotics (penicillins, sulfonamides, lincomycin, cephalosporins, aminoglycosides, tetracyclines, chloramphenicol, polymyxin B)

• Vaccines

• Allergen extracts

• Blood products

• Parasiticides (dichlorophen, levamisole, piperazine, dichlorvos, diethylcarbamazine, thiacetarsamide)

• Anesthetics/sedatives (acepromazine, ketamine, barbiturates, lidocaine, bupivacaine, narcotics, diazepam)

• Nonsteroidal antiinflammatory drugs (NSAIDs)

• Hormones (insulin, corticotropin, vasopressin, parathyroid hormone, glucocorticoids)

• Aminophylline

• Chemotherapeutics (doxorubicin, l-asparaginase, docetaxel, paclitaxel, etoposide)

• Iodinated contrast media

• Neostigmine

• Amphotericin B

• Enzymes (trypsin, chymotrypsin)

• Vitamins (vitamin K, thiamine, folic acid)

• Dextrans and gelatins

• Calcium disodium edetate

Foods

• Milk, egg white, shellfish, legumes, citrus fruits, chocolate, grains

Physical Factors

• Cold, heat, exercise

Anorexia

Primary Anorexia

• •Disinterest in eating; primary disease of appetite or satiety centers, rare

Secondary Anorexia (Common with Virtually any Systemic Disease)

• •Associate with nausea (gastrointestinal [GI] inflammation, ileus, delayed gastric emptying, vestibular disease, drug-induced nausea, food aversion)

Pseudoanorexia (Reluctance to Eat)

• •Retrobulbar abscess
• •Intraoral masses, foreign bodies
• •Mandibular fractures/temporomandibular joint disease
• •Masticatory myositis
• •Periodontal disease, gingivostomatitis
• •Salivary mucocele, sialadenitis, salivary tumor
• •Oropharyngeal dysphagia
• •Esophageal masses or foreign bodies
• •Nasal disease
• •Unpalatable diet
• •Anosmia

Behavioral

• •Social stress or conflict
• •Anxiety
• •Loss of companion

Anuria and Oliguria

Prerenal Azotemia

• Dehydration/hypovolemia

Acute Renal Failure

• One third of cases are anuric, one third are oliguric, and one third are nonoliguric; more likely to be oliguric/anuric with severe renal toxicosis

• Toxic: exogenous (drugs, biologic or environmental toxins), endogenous (calcium, pigments)

• Infectious: pyelonephritis, leptospirosis, infectious canine hepatitis, borreliosis, sepsis

• Ischemia: progression of prerenal azotemia, NSAIDs, vascular disease (avulsion, thrombosis, stenosis), shock, decreased cardiac output, deep anesthesia, extensive surgery, hypothermia, hyperthermia, hyperviscosity (polycythemia vera, multiple myeloma, extensive cutaneous burns, transfusion reaction, disseminated intravascular coagulation [DIC])

• Immune mediated: acute glomerulonephritis, SLE, transplant rejection, vasculitis

• Neoplasia: lymphoma

• Systemic disease with renal manifestations

  • •
    Infections (FIP, borreliosis, babesiosis, leishmaniasis, bacterial endocarditis)
  • •
    Pancreatitis
  • •
    Sepsis
  • •
    Multiple organ failure
  • •
    Heart failure
  • •
    SLE
  • •
    Hepatorenal disease
  • •
    Malignant hypertension

Postrenal Azotemia

• Obstruction (may appear similar to anuria/oliguria)

Anxiety and Phobias

Fears and Phobias

Fear: apprehension associated with the presence of an object, individual, or sound; may be normal or abnormal, depending on context

Phobia: quickly developed, immediate, profound abnormal response to a stimulus leading to catatonia or panic

People

• Babies, children, elderly

• People in uniform

• People who appear different from family members

  • •
    Color, height, facial hair

• Disabled people

• Men or women, depending on circumstance

Animals

• Same species

• Other species

Noise

• Especially gunshots, fireworks, thunder

Anxiety

Separation Anxiety

Initiators

• Change in owner’s routine

• Owner returning to school or work

• Move to new home

• Visit to new environment

• After stay in kennel

• New baby, new pet, new partner

• Medical, cognitive

Common Features of Separation Anxiety

• Hyperattached to owner

• Signs of anxiety as owner leaves

• Problems manifest when owner absent or when pet unable to gain access to owner

• Problem behavior begins shortly after owner leaves

• May even occur during short absences

• Pet shows exuberant greeting behavior

Generalized Anxiety

• Poorly socialized, nervous pet

Signs of anxiety

• •Hypervigilance, scanning
• •Increased motor activity (restlessness, pacing, circling)
• •Vocalization/whining
• •Displacement behaviors: out-of-context grooming and scratching, yawning, lip licking, whining and barking, destructive, digging
• •Changes in social soliciting behavior: increase or decrease in attention seeking
• •Hiding, escape attempts
• •Physiologic signs (trembling, dilated pupils, ptyalism, piloerection, ↑ respiratory rate, ↑ heart rate, urination, defecation, vomiting, anal sac expression)
• •Decreased appetite.

Ascites

See Abdominal Effusions and Ascites.

Ataxia and Incoordination

Forebrain Disease

• Typically, mild ataxia and other neurologic signs predominate.

  • Generalized disease: generalized ataxia
  • Unilateral disease: contralateral conscious proprioceptive deficits, mild gait disturbance
  • Postictal paraparesis: transient in nature

• Paraparesis may be a side effect of anticonvulsant therapy (especially potassium bromide).

Brain Stem

Hemiparesis or tetraparesis; lesions severe enough to cause paralysis usually result in respiratory arrest.

Vestibular nuclei may be affected, causing vestibular ataxia, head tilt, and nystagmus; distinguish central vestibular disease from peripheral vestibular disease by presence of ipsilateral conscious proprioceptive deficits.

Peripheral Vestibular Disease

Generalized ataxia accompanied by head tilt, rotary or horizontal nystagmus, positional strabismus, and oculovestibular eye movements

Conscious proprioceptive deficits absent

Cerebellum

Lesions cause dysmetria, usually hypermetria.

Unilateral lesions cause ipsilateral signs.

Cervical Spinal Cord

May cause forelimb monoparesis (lesions affecting spinal segments C6-T2), hemiparesis, tetraparesis; may progress to paralysis

Thoracic (T3-L3) Spinal Cord

• Mild to marked rear limb ataxia, paraparesis, paraplegia, monoparesis, or monoplegia

• Rear limb reflexes exaggerated

• Reduced to absent panniculus reflex caudal to lesion

Lumbosacral (L4-S2) Spinal Cord

• Mild to marked rear limb ataxia, paraparesis, paraplegia, monoplegia

• Reduced to absent rear limb reflexes

• May see bladder and anal sphincter hypotonia

Peripheral Nerve

• Mild to marked ataxia, paresis, paralysis of one or more limbs

• Degenerative, inflammatory, toxic, traumatic neuropathies

• Hyporeflexia usually seen

• Paresis or paralysis of muscle or muscles innervated by affected nerve

Blindness

Corneal Lesions

• Edema (trauma, glaucoma, immune-mediated keratitis such as keratouveitis caused by canine adenovirus-1, endothelial dystrophy, neurotropic keratitis)

• Keratoconjunctivitis sicca

• Exposure keratitis

• Superficial keratitis (pannus)

• Corneal melanosis (entropion, ectropion, lagophthalmos, facial nerve paralysis)

• Cellular infiltrate (bacterial, viral, fungal)

• Dystrophies (lipid, genetic)

• Fibrosis (scar)

Aqueous Humor Lesions

• Fibrin (anterior uveitis: many causes)

• Hypopyon (immune-mediated, neoplastic [lymphosarcoma], infectious [blastomycosis, cryptococcus, histoplasmosis, coccidioidomycosis, toxoplasmosis, FIP, protothecosis, brucellosis, septicemia])

• Hyphema (trauma, blood-clotting deficiencies, ehrlichiosis, rickettsia, systemic hypertension, retinal detachment, neoplasia)

• Lipid (hyperlipidemia with concurrent anterior uveitis to disrupt the blood–aqueous barrier)

Lens Lesions

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

Vitreous Humor Lesions

• Hemorrhage (trauma, systemic hypertension, clotting deficiency, neoplasia, retinal detachment)

• Hyalitis (numerous infectious diseases such as FIP, penetrating injury causing cellular infiltrate)

Retinal Lesions

• Glaucoma

• Sudden acquired retinal degeneration (SARD)

• Progressive retinal atrophy

• Central progressive retinal atrophy

• Toxicity (fluoroquinolone administration in cats)

• Systemic hypertension

• Retinal detachment

  • •
    Exudative/transudative (systemic hypertension, mycoses, rickettsial, toxoplasmosis, viral, bacterial, fungal)
  • •
    Neoplasia
  • •
    Retinal dysplasia
  • •
    Hereditary/congenital (e.g., Collie eye anomaly)

Failure to Transmit Visual Message

• Viral infections (canine distemper, FIP)

• Systemic and ocular mycoses (blastomycosis, cryptococcosis, histoplasmosis, coccidioidomycosis)

• Neoplasia

• Traumatic avulsion of optic nerve (traumatic proptosis)

• Granulomatous meningoencephalitis

• Hydrocephalus

• Optic nerve hypoplasia

• Coloboma

• Immune-mediated optic neuritis

Failure to Interpret Visual Message

• Canine distemper virus

• FIP

• Granulomatous meningoencephalitis

• Systemic mycoses

• Trauma

• Heat stroke

• Hypoxia

• Hydrocephalus

• Hepatoencephalopathy

• Neoplasia

• Storage diseases

• Postictal

• Meningitis

Bradycardia, Sinus

• Normal variation (fit animal)

• Hypothyroidism

• Hypothermia

• Drugs (tranquilizers, anesthetics, β-blockers, calcium entry blockers, digitalis)

• Increased intracranial pressure

• Brain stem lesion

• Severe metabolic disease (e.g., uremia)

• Ocular pressure

• Carotid sinus pressure

• High vagal tone

• Cardiac arrest (before and after)

• Sinus node disease

• Airway obstruction (causing high vagal tone)

Cachexia and Muscle Wasting

Cachexia

Certain chronic disease processes stimulate the release of cytokines that suppress appetite and stimulate hypercatabolism.

• Cardiac disease

• End-stage renal disease

• Chronic infection

• Chronic fever

• Chronic inflammation

• Neoplasia

Muscle Wasting

Endocrine Disease

• Hyperadrenocorticism

• Hyperthyroidism

• Hyperparathyroidism

Starvation

• Underfeeding

• Poor-quality feed

• Competition for food

• Dental disease

• Lactation, pregnancy

• Increased work

• Extreme cold environment

Impaired Ability to Use or Retain Nutrients

• Dysphagia, regurgitation, vomiting

• Maldigestion

• Malabsorption

• Parasitism

• Histoplasmosis

• Exocrine pancreatic insufficiency

• Diabetes mellitus

• Protein-losing nephropathy or gastroenteropathy

Inflammatory Myopathies

• Masticatory myositis

• Dermatomyositis

• Canine idiopathic polymyositis

• Feline idiopathic polymyositis

Protozoal Myositis

• Toxoplasma gondii

• Neospora caninum

Inherited Myopathies

• Muscular dystrophy

• Hereditary Labrador Retriever myopathy

Neurologic Disorders

• Spinal and peripheral neuropathies

• Disuse atrophy

Collapse

Differential Diagnosis of Collapse

Cardiovascular

• •Congestive heart failure
• •Arrhythmia
• •Arterial thromboembolism
• •Pulmonary hypertension
• •Cardiac tamponade

Respiratory

• •Laryngeal paralysis
• •Tracheal collapse
• •Asthma
• •Brachycephalic upper airway disease
• •Pulmonary edema
• •Pleural effusion
• •Pneumonia
• •Pharyngeal or laryngeal obstruction (mass, foreign body)
• •Lung lobe torsion

Metabolic/endocrine

• •Anemia
• •Hypoglycemia
• •Shock
• •Sepsis
• •Heat stroke
• •Hypoadrenocorticism
• •Anaphylaxis
• •Hypocalcemia
• •Hypokalemia

Brain/cranial nerves

• •Canine geriatric vestibular syndrome
• •Feline idiopathic vestibular syndrome
• •Hemorrhage
• •Neoplasia
• •Intoxication
• •Infarct
• •Encephalitis
• •Hydrocephalus

Spinal cord

• •Intervertebral disc disease
• •Trauma
• •Neoplasia
• •Discospondylitis
• •Hemorrhage
• •Fibrocartilaginous embolism
• •Meningitis/myelitis
• •Cervical spondylomyelopathy (Wobblers)

Partial seizures

• •Idiopathic epilepsy
• •Brain disease

Neuromuscular/musculoskeletal

• •Tick paralysis
• •Polyradiculoneuritis
• •Botulism
• •Myasthenia gravis
• •Polyarthritis, polyneuropathy, polymyositis

Compulsive Behavior Disorders

Compulsive Disorders in Dogs

Locomotor

• Spinning or tail chasing

• Stereotypic pacing/circling/jumping

• Fixation; staring/barking/freezing/scratching

• Chasing lights, reflections, shadows

• Barking; intense/rhythmic/difficult to interrupt

• Head bob/tremor/head shaking

• Attacking food bowl, attacking inanimate objects

Apparent Hallucinatory

• Air biting or fly snapping

• Staring, freezing, startled

• Star/sky gazing

Self-Injurious or Self-Directed

• Tail attacking, mutilation, growl/attack legs or rear

• Face rubbing/scratching

• Acral lick dermatitis, licking/chewing/barbering

• Nail biting

• Flank sucking

• Checking rear

Oral

• Sucking/licking

• Pica, rock chewing

• Polydipsia/polyphagia

• Licking of objects/owners

Compulsive Disorders in Cats

Locomotor

• Skin ripple/agitation/running, feline hyperesthesia

• Circling

• Freezing

• Excessive/intense chasing of imaginary objects

• Excessive vocalization/howling

Apparent Hallucinatory

• Staring at shadows/walls

• Startle

• Avoiding imaginary objects

Self-Injurious or Self-Directed

• Tail attacking, mutilation, growl/attack legs or rear

• Face scratching/rubbing

• Chewing/licking/barbering/overgrooming

• Nail biting

• Hyperesthesia

Oral

• Wool sucking

• Pica

• Polydipsia/polyphagia

• Licking of objects/owners

Constipation

Dietary Causes

• Excessive fiber in dehydrated patient

• Ingestion of hair, bones, indigestible materials

Colonic Obstruction

• Deviation of rectal canal: perineal hernia

• Intraluminal or intramural disorders

  • •
    Tumor
  • •
    Granuloma
  • •
    Cicatrix
  • •
    Rectal foreign body
  • •
    Congenital stricture

• Pseudocoprostasis

• Perineal hernia

• Extraluminal disorders

  • •
    Tumor
  • •
    Granuloma
  • •
    Abscess
  • •
    Healed pelvic fracture
  • •
    Prostatomegaly
  • •
    Prostatic or paraprostatic cyst
  • •
    Sublumbar lymphadenopathy

Behavioral or Environmental Causes

• Change in routine

• Soiled or absent litter box

• Refusal to defecate in house

• Inactivity

Drugs

• Opiates

• Anticholinergics

• Sucralfate

• Barium

Refusal to Defecate

• Pain in rectal or perineal area (perianal fistulas)

• Inability to posture to defecate (orthopedic or neurologic problem)

Colonic Weakness

Systemic Disease

• Hypercalcemia

• Hypokalemia

• Hypothyroidism

• Chagas disease

Localized Neuromuscular Disease

• Spinal cord disease

• Pelvic nerve damage

• Dysautonomia

• Chronic dilatation of colon/irreversible stretching of colonic musculature

Miscellaneous Causes

• Severe dehydration

• Idiopathic megacolon (cats)

Coughing

Disorders of Upper Airway

Inflammatory

• Pharyngitis

• Tonsillitis

• Tracheobronchitis

• Chronic bronchitis

• Allergic bronchitis

• Bronchiectasis

• Collapsed trachea

• Oslerus osleri infection

Neoplastic

• Mediastinal

• Laryngeal

• Tracheal

Allergic

• Bronchial asthma

Other

• Bronchial compression: left atrial enlargement, hilar lymphadenopathy

• Foreign body

• Inhalation

• Tracheal stenosis

Disorders of Lower Respiratory Tract

Inflammatory

Pneumonia

• Bacterial

• Viral: canine distemper virus

• Fungal: blastomycosis, histoplasmosis, coccidioidomycosis

• Protozoal: toxoplasmosis, pneumocystis pneumonia

• Aspiration pneumonia

Granuloma, Abscess

Chronic Pulmonary Fibrosis

Parasitic Disease

• Heartworm disease (Dirofilaria immitis)

• Lungworm disease (Aelurostrongylus abstrusus—cat; Paragonimus kellicotti—dog, cat; Capillaria aerophilia—dog, cat; Filaroides hirthi—dog; Crenosoma vulpis—dog; Angiostrongylus vasorum—dog)

Neoplasia

• Primary or metastatic

• Lymphoma

Cardiovascular

• Left-sided heart failure: pulmonary edema

• Pulmonary thromboembolism

Allergic

• Eosinophilic pneumonitis

• Eosinophilic pulmonary granulomatosis

• Pulmonary infiltrate with eosinophils (PIE)

Other

• Lung lobe torsion

• Systemic bleeding disorder

• Pleural effusion

• Neoplasia of chest wall

Cyanosis

Central Cyanosis

Cardiac

Intracardiac

• Tetralogy of Fallot

• Atrial or ventricular septal defect with pulmonic stenosis, tricuspid valve dysplasia, or pulmonary hypertension

• Transposition complexes (double outlet right ventricle, other)

Extracardiac

• Pulmonary arteriovenous fistulas

• Patent ductus arteriosus (reversed)

Pulmonary

Hypoventilation

• Pleural effusion

• Pneumothorax

• Respiratory muscle failure (fatigue, neuromuscular disease)

• Anesthetic overdose

• Primary neurologic disease

Obstruction

• Laryngeal paralysis

• Foreign body in airway

• Mass lesion of large airway (neoplasia, parasitic, inflammatory)

• Low oxygen concentration of inspired air (high altitude, anesthetic complications)

Ventilation-Perfusion Mismatch

• Pulmonary thromboembolism

• Pulmonary infiltrate (edema, inflammation/infection, neoplasia, acute respiratory distress syndrome, chronic obstructive pulmonary disease, fibrosis, pulmonary contusions/hemorrhage)

Methemoglobinemia

Peripheral Cyanosis

• Central cyanosis (heart failure)

• Decreased arterial supply

• Peripheral vasoconstriction (hypothermia, shock)

• Arterial thromboembolism

• Low cardiac output

• Obstruction of venous drainage

  • •
    Tourniquet or foreign object (e.g., rubber band)
  • •
    Venous thrombosis
  • •
    Right-sided heart failure

Deafness

Congenital Sensorineural Deafness

Inherited

• Many breeds of dogs

  • •
    Dalmatians
  • •
    Merle or dapple coat patterns in Collies, Shetland Sheepdogs, Great Danes, Dachshunds
  • •
    Piebald pattern in Dalmatians, Bull Terriers, Great Pyrenees, Sealyham Terriers, Greyhounds, Bulldogs, and Beagles
  • •
    Many other dog breeds affected

• White cats with blue irides and white coloration in some breeds of dogs

Congenital Acquired Sensorineural Deafness

• In utero exposure to bacteria, ototoxic drugs, low oxygen tensions, or trauma

Acquired Late-Onset Conductive Deafness

• Lack of transmission of sound through tympanic membrane and auditory ossicles

• Otitis externa/media

• Otic neoplasia

• Polyps

• Trauma-induced fluid accumulation in middle ear

• Atresia of tympanum or ossicles

• Fused ossicles

• Stenosis of ear canal leading to accumulation of fluid in middle ear

• Total ear canal ablation

Acquired Late-Onset Sensorineural Deafness

• Presbycusis (age-related hearing loss)

• Ototoxicity

• Chronic exposure to loud noise

• Hypothyroidism

• Trauma

• Bony neoplasia

Diarrhea, Acute

Diet

• Intolerance/allergy

• Rapid dietary change

• Bacterial food poisoning

• Dietary indiscretion

• Poor-quality food

Parasites

• Helminths

• Protozoa (Giardia, Trichomonas, Coccidia spp.)

Infections

• Viral (parvovirus, coronavirus, feline leukemia virus [FeLV], feline immunodeficiency virus [FIV], canine distemper virus, rotavirus)

• Bacterial (Salmonella spp., Clostridium perfringens, Escherichia coli, Campylobacter jejuni, Yersinia enterocolitica, other bacteria)

• Rickettsial

  • •
    Salmon poisoning

Other Causes

• Hemorrhagic gastroenteritis

• Intussusception

• Irritable bowel syndrome

• Toxins (chemicals, heavy metals, toxic plants, spoiled foods, garbage)

• Drugs (antibiotics, cancer chemotherapeutic agents, anthelmintics, nonsteroidal anti-inflammatory drugs [NSAIDs], digitalis, lactulose)

• Pancreatitis

• Hypoadrenocorticism

• Pyometra

• Peritonitis

Diarrhea, Chronic

Small Bowel Diarrhea

• Food intolerance or allergy

• Inflammatory bowel disease

• GI lymphoma

• Pancreatic exocrine insufficiency

• Chronic parasitism (hookworm, Giardia)

• Histoplasmosis

• Intestinal lymphangiectasia

• Partial obstruction

• Pancreatic carcinoma

• Gastrinoma

• Liver disease (hepatocellular failure, cholestasis)

• Endocrine disease (hypoadrenocorticism, hypothyroidism, hyperthyroidism)

• Renal disease (uremia, nephrotic syndrome)

• Chronic intussusception

• Small intestinal bacterial overgrowth

• Pythiosis

Large Bowel Diarrhea

• Food intolerance or allergy

• Parasitism (whipworm, Giardia, Trichomonas, Heterobilharzia)

• Clostridial colitis

• Irritable bowel syndrome (fiber-responsive)

• Histoplasmosis

• Pythiosis

• Inflammatory bowel disease

  • •
    Lymphocytic-plasmacytic colitis
  • •
    Eosinophilic colitis
  • •
    Chronic ulcerative colitis
  • •
    Histiocytic ulcerative colitis (Boxers)

• Neoplasia (lymphoma, adenocarcinoma)

• FeLV/FIV (infections secondary to these viruses)

Dyschezia

See Tenesmus and Dyschezia.

Dysphagia

Oral Lesions

• Fractured bones or teeth

• Periodontitis

• Trauma (laceration, hematoma)

• Feline resorptive lesions (caries)

• Osteomyelitis

• Retrobulbar abscess/inflammation

• Temporal-masseter myositis

• Stomatitis, glossitis, pharyngitis, gingivitis, tonsillitis, sialadenitis

  • •
    Immune-mediated disease
  • •
    Feline herpesvirus, calicivirus, leukemia virus, immunodeficiency virus
  • •
    Lingual foreign bodies or granulomas
  • •
    Tooth root abscess
  • •
    Uremia
  • •
    Caustic chemicals

• Cleft palate

• Lingual frenulum disorder

• Cricopharyngeal achalasia/asynchrony

Obstructive Lesion

• Esophageal stricture/foreign object

• Esophagitis

• Electric cord burns

• Neoplasia (malignant or benign)

• Inflammatory (abscess, polyp, granuloma)

• Lymphadenopathy

• Eosinophilic granuloma

• Foreign object (oral, pharyngeal, laryngeal)

• Sialocele

• Nasopharyngeal polyp

Neuromuscular Disease

• Myasthenia gravis

• Acute polyradiculitis

• Masticatory myositis

• Tick paralysis

• Botulism

• Polymyositis

• Temporomandibular joint disease

• Rabies

• Trigeminal nerve paralysis or neuritis

• Neuropathies of cranial nerves V, VII, IX, X, or XII

• Brain stem disease

• Tetanus

• Hypothyroidism

Dyspnea

Inspiratory Dyspnea

Nasal Obstruction

• Rhinitis

  • •
    Viral: feline herpesvirus, feline calicivirus, canine distemper virus
  • •
    Bacterial
  • •
    Fungal: aspergillosis, cryptococcosis, penicilliosis, rhinosporidiosis

• Neoplasia: adenocarcinoma, squamous cell carcinoma, fibrosarcoma, osteosarcoma, chondrosarcoma, lymphoma, transmissible venereal tumor

• Stenotic nares

• Nasal foreign body

• Thick nasal discharge of any etiology

Pharyngeal or Laryngeal Disease

• Elongated soft palate, everted laryngeal saccules

• Neoplasia/mass, abscess, granuloma, extraluminal mass

• Nasopharyngeal polyp

• Foreign body

• Laryngeal paralysis, acute/obstructive laryngitis, laryngeal collapse, laryngeal trauma

Extrathoracic Trachea

• Collapsing trachea

• Tracheal hypoplasia

• Tracheal trauma/stricture, foreign body, neoplasia

Expiratory or Mixed Dyspnea

Intrathoracic Trachea and Bronchi

• Collapsing trachea or main-stem bronchus

• Trauma, stricture, foreign body, neoplasia

• Small airway disease

• Feline asthma

• Bronchitis

• Smoke inhalation

• Bronchopneumonia

Pulmonary Parenchymal Disease

• Pneumonia (viral, bacterial, fungal, protozoal, aspiration)

• Pulmonary edema

• Pulmonary thromboembolism

• Bronchial asthma

• Chronic obstructive lung disease

Parasites/Severe Infestations/Heartworm, Lungworms

• Pulmonary fibrosis

• Neoplasia

Pleural Space Disease

• Pleural effusion

• Pneumothorax

• Pleural space masses

• Diaphragmatic hernia

Noncardiopulmonary Disease

• Severe anemia

• Hypovolemia

• Acidosis

• Hyperthermia

• Neurologic disease

Dysuria

See Stranguria, Dysuria, and Pollakiuria.

Ecchymoses

See Petechiae and Ecchymoses.

Edema

Increased Hydrostatic Pressure

Impaired Venous Return

• Congestive heart failure

• Constrictive pericarditis

• Ascites (cirrhosis)

• Budd–Chiari syndrome

• Venous obstruction or compression (thrombosis, external pressure, extremity inactivity)

• Iatrogenic overhydration

• Heartworm disease

Small-Caliber Arteriolar Dilatation

• Heat

• Neurohumoral dysregulation

Reduced Plasma Osmotic Pressure

Hypoproteinemia

• Cirrhosis (ascites)

• Malnutrition

• Protein-losing enteropathy

• Protein-losing glomerulonephropathy (nephrotic syndrome)

• Lymphangiectasia

Lymphatic Obstruction

• Various inflammatory causes

• Neoplasia

• Postsurgical

• After radiation therapy

Sodium Retention

• Excessive dietary intake with renal disease

• Renal hypoperfusion

• Increased renin–angiotensin–aldosterone secretion

Inflammation

• Acute and chronic

• Angiogenesis

Increased Microvascular Permeability

• Sepsis

• Acute respiratory distress syndrome

• Pancreatitis

• Infection (fungal, bacterial, viral)

Mixed Mechanisms

• Noncardiogenic pulmonary edema (head trauma, seizures, electrocution, upper airway obstruction)

• Anaphylaxis

• Organ torsion

Epistaxis

Systemic Causes

• Thrombocytopenia

  • •
    Decreased production of thrombocytes (infectious, myelophthisis secondary to neoplasia, drugs, immune-mediated phenomena)
  • •
    Increased destruction (immune mediated, microangiopathy)
  • •
    Increased consumption (DIC, vasculitis, hemorrhage)
• Thrombocytopathia

  • •
    Primary (von Willebrand disease)
  • •
    Secondary (uremia, ehrlichiosis, multiple myeloma, drugs such as NSAIDs)

• Coagulation factor defects (e.g., hemophilia A and B)

• Acquired coagulopathies (anticoagulant rodenticides, hepatic failure)

• Increased capillary fragility (hypertension, hyperviscosity syndromes [multiple myeloma, ehrlichiosis, leishmaniasis], hyperlipidemia, thromboembolic disease)

• Polycythemia

• Systemic hypertension

Local Causes

• Neoplasia (nasal adenocarcinoma, lymphoma, benign polyps)

• Foreign body

• Bacterial infection (usually secondary; rarely, Bordetella, Pasteurella, or Mycoplasma can be primary cause of epistaxis)

• Fungal rhinitis (Aspergillus, Cryptococcus spp.)

• Dental disease with oronasal fistulation

• Nasal parasites: Pneumonyssus caninum (nasal mite), Eucoleus boehmi (formerly Capillaria spp.), Cuterebra spp.

• Eosinophilic and lymphoplasmacytic rhinitis (uncommon)

• Arteriovenous malformations

Erosions and Ulcers of Skin and Mucous Membranes

Canine Diseases

Infectious

• •Bacterial pyoderma
• •Surface: acute moist dermatitis (pyotraumatic dermatitis), intertrigo
• •Deep: folliculitis/furunculosis (including pyotraumatic folliculitis), oral bacterial infections

Fungal

• •Yeast infections (Malassezia pachydermatis, Candida spp.), systemic/subcutaneous

Parasitic

• •Demodecosis

Metabolic

• •Calcinosis cutis (hyperadrenocorticism)
• •Uremia/renal failure
• •Necrolytic migratory erythema/metabolic epidermal necrosis

Neoplastic

• •Epitheliotropic lymphoma
• •Squamous cell carcinoma

Physical, Chemical

• •Drug reactions
• •Solar injury
• •Thermal injury (freeze, burn)
• •Urine scald

Immune Mediated/Autoimmune

• •DLE, vesicular cutaneous erythematosus
• •Pemphigus group
• •Uveodermatologic syndrome
• •Miscellaneous autoimmune subepidermal vesiculobullous diseases: bullous pemphigoid, epidermolysis bullosa acquisita, linear IgA bullous disease, mucocutaneous pemphigoid, bullous systemic lupus type 1

Miscellaneous

• •Arthropod bites
• •Dermatomyositis
• •Dystrophic epidermolysis bullosa
• •Idiopathic ulceration of Collies
• •Junctional epidermolysis bullosa
• •
  Toxic epidermal necrolysis/erythema multiforme

  • •
    Junctional epidermolysis bullosa
  • •
    Acral mutilation syndrome (French Spaniel, German and English Pointers)
  • •
    Cutaneous asthenia (Ehler–Danlos syndrome

Feline Diseases

Infectious

• •Viral: calicivirus and herpesvirus
• •Bacterial: atypical mycobacteriosis
• •Fungal: subcutaneous (e.g., sporotrichosis) and systemic mycoses (e.g., cryptococcosis)

Metabolic

• •Uremia/renal disease

Neoplastic

• •Fibrosarcoma
• •Lymphoma
• •Squamous cell carcinoma

Physical/Chemical

• •Drug reactions
• •Thermal

Immune Mediated/Autoimmune

• •Bullous pemphigoid
• •Pemphigus foliaceous
• •Toxic epidermal necrolysis/erythema multiforme

Miscellaneous/Idiopathic

• •Arthropod bites
• •Dystrophic epidermolysis bullosa
• •Eosinophilic plaque
• •Idiopathic ulceration of dorsal neck
• •Indolent ulcer
• •
  Junctional epidermolysis bullosa

  • •
    Skin fragility syndrome
  • •
    Cutaneous asthenia (Ehler–Danlos syndrome)

Failure to Grow/Failure to Thrive

Small Stature and Poor Body Condition

• Dietary insufficiency

• Underfeeding

• Poor-quality diet

• GI disease

  • •
    Parasitism
  • •
    Inflammatory bowel disease
  • •
    Food intolerance/allergy
  • •
    Obstruction (foreign body, intussusception)
  • •
    Histoplasmosis
• Hepatic dysfunction

  • •
    Portovascular anomaly
  • •
    Hepatitis
  • •
    Glycogen storage disease
• Cardiac disorder

  • •
    Congenital anomaly
  • •
    Endocarditis

• Pulmonary disease

• Esophageal disease

  • •
    Megaesophagus
  • •
    Vascular ring anomaly (persistent right aortic arch)

• Exocrine pancreatic insufficiency

• Renal disease

• Renal failure (congenital or acquired)

  • •
    Glomerular disease
  • •
    Pyelonephritis

• Inflammatory disease

• Glycogen storage disease

• Hormonal disease

  • •
    Diabetes mellitus
  • •
    Hypoadrenocorticism
  • •
    Diabetes insipidus
  • •
    Juvenile hyperparathyroidism

Small Stature and Good Body Condition

• Chondrodystrophy

• Hormonal disease

  • •
    Congenital hypothyroidism
  • •
    Congenital hyposomatotropism (pituitary dwarfism)
  • •
    Hyperadrenocorticism

Fever of Unknown Origin

Infection

Bacterial

• Abscessation (inapparent subcutaneous, stump pyometra, liver, pancreas, tooth root, retrobulbar)

• Pyelonephritis

• Diskospondylitis

• Osteomyelitis

• Pneumonia

• Prostatitis

• Peritonitis

• Pyothorax

• Closed pyometra

• Splenic abscess

• Septic arthritis

• Sepsis

• Cholangiohepatitis (cat)

• Bartonellosis

• Mycoplasma haemofilis (formerly Hemobartonella felis)

• Borreliosis

• Brucellosis

• Leptospirosis

• Mycobacteriosis l-form bacteria (cat)

• Mycoplasmosis

• Salmonellosis

• Tularemia

• Bacterial endocarditis

• Plague

• Tuberculosis

Fungal

• Blastomycosis

• Histoplasmosis

• Coccidioidomycosis

• Cryptococcosis

• Systemic aspergillosis

Viral

• Canine distemper

• Canine influenza

• FIV

• FeLV

• FIP (Coronavirus)

Rickettsial

• Rocky Mountain spotted fever

• Ehrlichiosis

• Anaplasmosis

• Salmon poisoning

Protozoal

• Toxoplasmosis

• Babesiosis

• Hepatozoonosis

• Cytauxzoonosis

• Trypanosomiasis (Chagas disease)

• Leishmaniasis

• Neosporosis

Neoplasia

• Lymphoma

• Multiple myeloma

• Leukemia

• Histiocytic sarcoma

• Necrotic solid tumors

Immune Mediated

• Polyarthritis

• Vasculitis

• Meningitis

• SLE

• Pemphigus

• Rheumatoid arthritis

• Immune-mediated hemolytic anemia

• Immune-mediated thrombocytopenia

• Meningoencephalitis (granulomatous, necrotizing)

• Steroid-responsive fever

• Steroid-responsive neutropenia

Inflammatory

• •Hypertrophic osteodystrophy
• •Juvenile cellulitis
• •Pancreatitis
• •Panniculitis
• •Panosteitis
• •Pansteatitis

Other

• Hyperthyroidism

• Tissue damage

• Pharmacologic agents

  • •
    Tetracycline
  • •
    Penicillins
  • •
    Sulfas

• Metabolic bone disease

• Portosystemic shunt

• Hypothalamic disease

• Shar-Pei fever

• Idiopathic

Flatulence

• Dietary intolerance (high-fiber, high-protein, or high-fat foods; high-sulfur diets; spoiled food; food change)

• Maldigestion

  • •
    Exocrine pancreatic insufficiency
  • •
    Lactose intolerance

• Malabsorption

• Motility disorders (disrupt passage of gas)

• Aerophagia

• Behavior (aerophagia associated with competitive eating habits)

• Various gastrointestinal disorders

Gagging

Nutritional

• Food texture

• Food size

Infectious

• Viral encephalitis (rabies, pseudorabies)

• Fungal (focal, systemic)

• Bacterial encephalitis

Toxic

• Chemical (caustic chemicals, smoke)

• Botulism

Developmental

• Cleft palate

• Hydrocephalus

• Achalasia

Degenerative

• Laryngeal paralysis

• Muscular dystrophy

• Myasthenia gravis

• Neuropathy of cranial nerves V, VII, IX, or XII

Mechanical

• Foreign body

• Styloid disarticulation

Metabolic

• Uremia

• Hypocalcemia

Neoplasia

• Tonsils, pharynx, epiglottis, glottis, inner ear, nasal, central nervous system

Trauma

• Tracheal rupture

• Pharyngeal hematoma

• Medulla or pons ischemia or edema

Allergic or Immune Mediated

• Rhinitis

• Pharyngitis

• Laryngitis

• Asthma

• Granuloma complex

• Idiopathic glossopharyngitis

Genital Dermatoses

Lesions of the Prepuce/Sheath

• Bacterial folliculitis/furunculosis

• Allergic dermatitis affecting the abdomen with hyperpigmentation/lichenification/hypertrophy of the sheath

• Localized demodicosis

• Vasculitis

• Autoimmune skin diseases

• Linear dermatosis of the prepuce (estrogen-secreting tumor)

• Linear epidermal nevus

• Vascular nevus

• Various neoplasms (Stricker sarcoma, hemangiosarcoma, mast cell tumor)

Lesions of the Scrotum

• Contact dermatitis (most common scrotal skin disease)

• Frostbite, solar erythema, trauma

• Intertrigo

• Malassezia dermatitis

• Protothecosis

• Babesiosis

• Cuterebriasis

• Brucellosis

• Infection with Erysipelothrix rhusiopathiae

• Rocky Mountain spotted fever

• Superficial necrolytic dermatitis

• Autoimmune diseases (bullous diseases, lupus)

• Erythema multiforme

• Fixed pigmented erythema

• Cutaneous histiocytosis

• Vascular hamartoma

• Neoplasms (squamous cell carcinoma, apocrine adenocarcinoma, myxoma and fibrosarcoma, hemangioma, recurrent cystic hemangioma and hemangiosarcoma, plasmocytoma, lymphoma, histiocytoma, benign fibrous histiocytoma, mast cell tumor, melanoma)

Female

• Intertrigo

• Allergic dermatitis affecting the abdomen with hyperpigmentation/lichenification/hypertrophy of the vulva

• Malassezia dermatitis

• Demodicosis

• Bacterial furunculosis

• Contact dermatitis

• Autoimmune diseases (lupus, bullous diseases)

• Endocrine disorders (especially hyperestrogenism)

• Neoplasms

Halitosis

Oral Disease

• Periodontal disease (gingivitis, periodontitis, abscessation)

• Calculus

• Food traps (periodontal pockets, exposed tooth roots, oral ulcers)

• Neoplasia (melanoma, fibrosarcoma, squamous cell carcinoma)

• Foreign body

• Trauma/fracture

• Electric cord injury

• Pharyngitis

• Stomatitis/glossitis

Metabolic Disease

• Renal failure (uremia)

• Diabetic ketoacidosis

Gastrointestinal Disease

• Megaesophagus

• Inflammatory bowel disease

• Exocrine pancreatic insufficiency

• Neoplasia

• Constipation

Respiratory Disease

• Rhinitis/sinusitis

• Neoplasia

• Pneumonia or pulmonary abscess

Dermatologic Disease

• Lip fold pyoderma

• Eosinophilic granuloma

• Ulcerative mucocutaneous pyoderma

• Pemphigus complex

• Bullous pemphigoid

• Lupus erythematosus

• Drug eruption

• Cutaneous lymphoma

• Exposure to dimethyl sulfoxide (DMSO)

Dietary

• Aromatic foods (onions, garlic)

• Fetid food (carrion)

• Coprophagy

Grooming Behavior

• Anal sacculitis

• Vaginitis/balanoposthitis

• Lower urinary tract infections

• Hair retained in periodontal pockets

Head Tilt

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

• Hypothyroidism (possibly)

• Congenital (German Shepherd, Doberman Pinscher, English Cocker Spaniel, Siamese and Burmese cats)

Central Vestibular Disease

• Trauma/hemorrhage

• Infectious inflammatory disease

  • •
    Rocky Mountain spotted fever
  • •
    FIP
  • •
    Bacterial
  • •
    Protozoal
  • •
    Mycotic
  • •
    Rickettsial
  • •
    Others

• Granulomatous meningoencephalitis

• Neoplasia (meningioma, choroid plexus tumors)

• Vascular infarct

• Thiamine deficiency

• Metronidazole toxicity

• Viral (canine distemper virus, FIP)

• Toxic (lead, hexachlorophene)

• Degenerative diseases (storage diseases, neuronopathies, demyelinating diseases)

• Hydrocephalus

Hematemesis

Alimentary Tract Lesion

Gastritis

• Acute gastritis (common cause)

• Hemorrhagic gastroenteritis

• Chronic gastritis

• Helicobacter-associated disease

Heavy Metal Intoxication

Arsenic, lead, zinc

Gastrointestinal Tract Ulceration/Erosion

Iatrogenic

• NSAIDs

• Corticosteroids

• NSAIDs used in combination with corticosteroids

Infiltrative Disease

• Neoplasia

• Inflammatory bowel disease

• Pythiosis (young dogs, southeastern United States)

• Stress ulceration

  • •
    Hypovolemic shock
  • •
    Septic shock
  • •
    After gastric dilatation/volvulus
  • •
    Neurogenic shock
  • Burns
  • Multiple trauma
• Hyperacidity

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

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

Esophageal Disease (Uncommon)

• Tumor

• Severe esophagitis

• Trauma

Coagulopathy

• Thrombocytopenia/platelet dysfunction

• Clotting factor deficiency

• DIC

• Anticoagulant rodenticide

Extraalimentary Tract Lesion

• Respiratory tract lesion

• Lung lobe torsion

• Pulmonary tumor

• Posterior nares lesion

Hematochezia

Anal Disease

• Perianal fistulas

• Anal sacculitis or abscess

• Stricture

• Neoplasia (perianal adenoma, anal sac adenocarcinoma)

• Anal trauma

• Perineal hernia

• Foreign body

Rectal and Colonic Disease

• Hemorrhagic gastroenteritis

• Proctitis

• Colitis

  • •
    Idiopathic
  • •
    Dietary allergy
  • •
    Inflammatory bowel disease
  • •
    Stress
  • •
    Infectious (Campylobacter spp., Clostridium perfringens)
  • •
    Histoplasmosis
  • •
    Pythiosis
  • •
    Food allergy
  • •
    Trichomoniasis (cat)

• Parvovirus

• Parasites

  • •
    Whipworms
  • •
    Hookworms
  • •
    Coccidia
• Neoplasia

  • •
    Rectal polyp
  • •
    Adenocarcinoma
  • •
    Lymphoma
  • •
    Leiomyoma or leiomyosarcoma

• Prolapsed rectum

• Mucosal trauma

  • •
    Foreign body or foreign material
  • •
    Pelvic fractures
  • •
    Iatrogenic (thermometers, enemas, fecal loops, rectal palpation)

• Iliocecal intussusceptions

Hematuria

Renal or Lower Urinary Tract Disease

• Inflammation/infection

• Urolithiasis

• Obstruction

• Trauma (catheter collection, cystocentesis, renal biopsy, blunt trauma)

• Neoplasia

• Bleeding disorder (anticoagulant intoxication, DIC, thrombocytopenia)

• Heat stroke

• Renal infarct

• Granulomatous urethritis

• Feline lower urinary tract disease (FLUTD)

• Parasitism (Dioctophyma renale, Capillaria plica)

• Drug induced (cyclophosphamide)

• Renal pelvic hematoma

• Vascular malformation

• Idiopathic renal hematuria

• Renal telangiectasia of Welsh Corgis

• Renal hematuria of Weimaraners

• Pseudohematuria (myoglobin, hemoglobin, drugs, dyes)

Extraurinary Disease

• Prostatic disease (infection, tumor, cyst, abscess)

• Uterine disease (pyometra, proestrus, tumor, subinvolution of placental sites)

• Vaginal (trauma, neoplasia)

• Estrus

• Preputial/penile (trauma, neoplasia)

Hemoptysis

Cardiovascular

• Heartworm disease

• Cardiogenic pulmonary edema

• Arteriovenous fistula

• Bacterial endocarditis

Pulmonary

• Thromboembolism (secondary to neoplasia, endocrine, cardiac, metabolic disease)

• Bacterial pneumonia

• Pulmonary abscess

• Nocardiosis

• Bordetella bronchiseptica infection

• Chronic bronchitis/bronchiectasis

• Fungal pneumonia (blastomycosis, coccidiomycosis, histoplasmosis)

• Neoplasia (hemangiosarcoma, primary adenocarcinoma, undifferentiated carcinoma, squamous cell carcinoma, chondrosarcoma, metastatic or primary tracheal tumors)

• Lung lobe torsion

• Parasites (Paragonimus kellicotti, Capillaria aerophila, Aelurostrongylus abstrusus)

• Pulmonary infiltrate with eosinophils

• Systemic bleeding disorder

  • •
    Primary (quantitative or qualitative platelet defects)
  • •
    Secondary (factor deficiencies, anticoagulant rodenticide toxicity, DIC)

• Trauma (pulmonary contusion, tracheal rupture, foreign body)

• Iatrogenic (endotracheal intubation, complication of lung biopsy/aspirate, transtracheal wash, bronchoscopy)

Hemorrhage, Prolonged

See Part Two, Section V: Differential Diagnosis for Thrombocytopenia, Platelet Dysfunction, and Coagulopathies, Inherited and Acquired.

Horner Syndrome

2.5% phenylephrine eye drops applied

No Pupillary Dilation (Assume Preganglionic Lesion)

• First order (central)

• Intracranial disease (neoplasia, trauma, infarct)

• First cervical to third thoracic (C1-T3) spinal myelopathy (intervertebral disc disease, neoplasia, fibrocartilaginous embolism, trauma)

• Second order (preganglionic)

• Spinal cord lesion T1-T3 (trauma, neoplasia, fibrocartilaginous embolism)

• Thoracic disease (cranial mediastinal mass, thoracic spinal nerve root tumor)

• Brachial plexus avulsion

• Cervical soft tissue neoplasia, trauma

• Skull base tumor

• Jugular furrow disease

Pupillary Dilation (Assume Postganglionic Lesion)

• Third order (postganglionic)

  • FeLV, FIV
  • Otitis media/interna
  • Otic mass
  • Retrobulbar injury, neoplasia
  • Idiopathic

Hyperemia

Differential Diagnosis of Hyperemia

Regional hyperemia

• •Allergen exposure (contact, insect/mite bite)
• •External constriction (rubber band, collar, identification band, tight bandage)
• •Internal obstruction

Generalized hyperemia

• •Hyperthermia induced (infectious, inflammatory, immune mediated, neurogenic, environmental, toxic)
• •Anaphylaxis/drug reaction
• •Mast cell tumor
• •Contact dermatitis
• •Carbon monoxide intoxication
• •Pheochromocytoma
• •Decreased venous return (cardiac, hepatic, venous occlusion)

Hyperpigmentation

Increased melanin in the epidermis

Hereditary Hyperpigmentation

• Lentigines—darkly pigmented macules that develop on the ventral abdomen of healthy adult dogs and on the lips, nose, gingiva, and eyelids of orange cats. No adverse health effects.

• Canine acanthosis nigricans—bilateral hyperpigmentation and lichenification of axillary skin. Primary, hereditary form seen in Dachshunds beginning before age 1. When seen in older Dachshunds or other breeds, it is likely a postinflammatory form seen with friction, intertrigo, allergies, or endocrine disease.

• Acromelanism—dark areas on the points of Siamese, Himalayan-Persian, Balinese, and Burmese cats. Result of a temperature-dependent enzyme controlling melanin production in hair bulbs.

Acquired Hyperpigmentation

• Postinflammatory—Mediators of inflammation (e.g., leukotrienes, thromboxanes) stimulate melanocytes to increase melanin production, which down-regulates inflammation by scavenging free radicles. Examples of inflammatory conditions that lead to increased melanin production include allergies, Malassezia dermatitis, bacterial pyoderma, dermatophytosis, demodecosis, scabies, and actinic and intertrigo dermatitis. Inflammation affecting hair follicles may lead to melanotrichia (e.g., sebaceous adenitis, panniculitis, vaccine reactions).

• Endocrine—hyperadrenocorticism, hypoadrenocorticism, hypothyroidism, hyperestrogenism, and other sex hormone imbalances may result in diffuse hyperpigmentation.

• Papillomavirus associated—Pugs may be at risk for development of papillomavirus-associated, slightly raised, scaly, hyperpigmented macules and plaques in their groin region, abdomen, ventral thorax, and neck. Similar lesions are described in Miniature Schnauzers, American Staffordshire Terriers, and Pomeranians. May transform to squamous cell carcinoma.

• Pigmented tumors—apocrine cysts are bluish, cutaneous hemangiomas and hemangiosarcomas appear red, dark purple, or bluish-black Melanomas, melanocytomas, and basal cell tumors are frequently black. Squamous cell carcinomas, trichoblastomas, and fibromas also may be dark brown to black.

Hyperthermia

Fever

• Exogenous pyrogens (infectious agents and their products, inflammation or necrosis of tissue, immune complexes, pharmacologic agents, bile acids)

• Endogenous pyrogens (fever-producing cytokines)

Heat Stroke

• High ambient temperatures

• Exercise

• Poor ventilation

• Brachycephalic conformation

• Obesity

Exercise Hyperthermia

• Sustained exercise

• Seizure disorders (especially prolonged or cluster seizures)

• Hypocalcemic tetany (eclampsia)

Pathologic Etiologies

• Lesions in or around anterior hypothalamus

• Hypermetabolic disorders

• Hyperthyroidism

• Pheochromocytoma

• Malignant hyperthermia

• Halothane

• Succinylcholine

• Phenothiazines

Hypopigmentation

• Due to melanocyte destruction, dysfunction, or abnormal distribution of melanosomes

Hereditary Hypopigmentation

• Albinism—hereditary absence of pigment

• Piebaldism—presence of white spots where melanocytes are absent

• Waardenburg–Klein syndrome—affected animals have absence of melanocytes in areas of skin and hair, blue or heterochromatic eyes, and are also deaf. Reported in cats, Bull Terriers, Sealyham Terriers, Collies, and Dalmatians.

• Canine cyclic hematopoiesis—lethal autosomal-recessive disease of Collies. Gray coat, light-colored nose, cyclic episodes of neutropenia every 12-14 days resulting in sepsis and amyloidosis.

• Chédiak–Higashi syndrome—rare autosomal-recessive disease of blue smoke Persian cats. Partial oculocutaneous albinism with abnormal function of granulocytes and platelets resulting in hemorrhage, recurrent infections, and death at a young age.

• Graying—age-associated reduction of melanocyte replication

• Vitiligo—macular leukoderma and leukotrichia of nose, ears, buccal mucosa, and facial skin. Antimelanocyte antibodies found in serum of some affected dogs. Seen most commonly in Siamese cats, Belgian Tervuren, German Shepherd, Collie, Rottweiler, Doberman Pinscher, Giant Schnauzer.

• Nasal hypopigmentation—season-associated lightening of nasal planum during winter months most common in Siberian Husky, Golden Retriever, Labrador Retriever, and Bernese Mountain Dog. Seen also in many other breeds.

• Mucocutaneous hypopigmentation—leukoderma of the nasal planum, lips, eyelids, tongue, and oral cavity. Many breeds of dogs, but more common in Australian Shepherds, Siberian Huskies, Golden Retrievers, and Labrador Retrievers. Congenital condition in Rottweilers and Doberman Pinschers.

• Tyrosinase deficiency—rare condition in Chow Chows. Puppies show dramatic color change, bluish-black tongue turns pink, hair shafts turn white. Melanin reappears spontaneously in 2-4 months.

Acquired Hypopigmentation

• Postinflammatory—DLE is the most common cause of postinflammatory nasal depigmentation. Also pemphigus complex, SLE, uveodermatologic syndrome, bullous pemphigoid, mucocutaneous pyoderma, drug eruption, and contact dermatitis. Infectious causes include leishmaniasis, blastomycosis, sporotrichosis, and bacterial folliculitis.

• Drug related—ketoconazole, procainamide, and vitamin E may cause diffuse coat lightening.

• Nutritional/metabolic—deficiencies of zinc, pyridoxine, pantothenic acid, and lysine are associated with graying of hair. Dark hairs may become reddish in color with copper deficiency, hypothyroidism, hyperadrenocorticism, hyperestrogenism, hyperprogesteronism, chlorine exposure, and chronic exposure to ultraviolet light.

• Neoplasia associated—nasal depigmentation, leukoderma, and leukotrichia sometimes seen with epitheliotropic T-cell lymphoma, basal cell tumors, mammary adenocarcinoma, and gastric carcinomas.

• Idiopathic—leukotrichia and patchy hypopigmentation reported as idiopathic in Labrador Retrievers and black Newfoundlands. Siamese cats may be affected with periocular leukotrichia, which may be associated with upper respiratory tract infections, pregnancy, dietary deficiencies, or systemic illness.

Hyphema

Causes of Hyphema

Genetic/breed predisposition

• •Hereditary coagulopathies
• •
  Breeds predisposed to retinal detachment

  • 1.
    Retinal dysplasia: presumed autosomal-recessive trait, (English Springer Spaniel, Bedlington Terrier, American Cocker Spaniel, Miniature Schnauzer); incomplete dominant inheritance in breeds with associated skeletal deformities (Labrador Retriever, Samoyed)
  • 2.
    Multifocal retinopathy: autosomal recessive in Coton de Tulear, Great Pyrenees, Australian Shepherd
  • 3.
    Collie eye anomaly (Collies, Shetland Sheepdog, Border Collie, Australian Shepherd)
  • 4.
    Shih Tzus are predisposed to vitreous degeneration and rhegmatogenous (retina is torn) retinal detachments
• •Persistent hyperplastic primary vitreous in Doberman Pinschers

Stimuli for intraocular neovascularization

• •Retinal detachments
• •Intraocular neoplasia
• •Glaucoma
• •Uveitis

Predisposition to ocular trauma

• •Blind animals
• •Hunting dogs
• •Exophthalmic animals
• •Puppies exposed to cats

Systemic diseases that cause vasculopathy and/or bleeding disorders

• •Systemic hypertension
• •Lymphoma
• •Hyperviscosity syndromes (multiple myeloma, polycythemia vera)
• •Infectious disease (feline leukemia virus, feline infectious peritonitis, rickettsial diseases)
• •Immune-mediated thrombocytopenia or anemia
• •Anticoagulation rodenticide intoxication

Hypothermia

Predisposing Factors

• Anesthesia

• Low ambient temperature

• Neonate

• Small size

• Elderly

• Sick

• Debilitated

• Near drowning

• Enema

Systemic Disease

• •Cardiac disease
• •Hypothyroidism
• •Sepsis
• •Chronic kidney disease
• •Hypoadrenocorticism
• •Malnourished
• •Hypoglycemia
• •Neurologic disease (head trauma, neoplasia, cerebral vascular disease)

Icterus (Jaundice)

Hemolysis

• Autoimmune hemolytic anemia

• Hemolytic anemia secondary to drugs, neoplasia

• Infectious (Ehrlichia canis, Babesia canis, Babesia felis, Mycoplasma hemocanis, Mycoplasma hemofelis, Cytauxzoon felis, heartworm disease, FeLV)

• Toxic (onions, lead, copper, methylene blue, benzocaine, propylene glycol, acetaminophen [cats], phenazopyridine)

• Fragmentation (DIC, hemangiosarcoma, vena cava syndrome)

• Erythrocyte membrane or enzyme defects (pyruvate kinase deficiency [Beagle, Basenji], phosphofructokinase deficiency [English Springer Spaniel], stomatocytosis of chondrodysplastic [Malamutes])

• Congenital porphyria

• Snake, brown recluse spider, and bee venoms

Hepatobiliary Disease

• Cholangiohepatitis

• Chronic inflammatory hepatic disease

• Cirrhosis

• Diffuse neoplasia

• Copper toxicity

• Toxic hepatopathy (anticonvulsants, mebendazole, oxibendazole, diethylcarbamazine, inhalation anesthetics, thiacetarsamide, acetaminophen, trimethoprim-sulfa)

• Hepatic lipidosis

• FIP

• Parasitic

• Idiosyncratic drug reaction

Posthepatic Biliary Obstruction

• Pancreatitis

• Enteritis/cholecystitis

• Trauma

• Neoplasia

• Calculus

• Stricture

• Mucocele

• Ruptured bile duct or gallbladder

Inappropriate Elimination

Dogs

Medical Causes

Fecal House Soiling

• Increased volume of feces (maldigestion, malabsorption, high-fiber diets)

• Increased frequency of voiding (colitis, diarrhea)

• Compromised neurologic function (peripheral nerve impairment, spinal cord disease, brain tumor, encephalitis, infection, degenerative brain disorders)

• Joint pain

• Sensory decline

• Cognitive dysfunction

Urinary House Soiling

• Diseases causing polyuria (e.g., renal disease, hyperadrenocorticism, diabetes, pyometra)

• Increased urinary frequency (urinary tract infection/inflammation, urolithiasis, bladder tumors, prostatitis, abdominal masses)

• Impaired bladder control (peripheral nerve disease, spinal cord disease, brain tumor, encephalitis, infection, degenerative brain disorders)

• Urethral incompetence

• Anatomic problems

• Urethral sphincter mechanism incompetence (estrogen-responsive incontinence)

• Cognitive dysfunction

Behavioral Causes

• Inadequate training

• Submissive urination

• Excitement urination

• Marking

• Separation anxiety

• Management-related problems

• Location or surface preference

Cats

Medical Causes

Fecal House Soiling

• Increased volume of feces (maldigestion, malabsorption, high-fiber diets)

• Increased frequency of voiding (colitis, diarrhea, inflammatory bowel disease)

• Compromised neurologic function (peripheral nerve impairment, spinal cord disease, brain tumor, encephalitis, infection, degenerative brain disorders)

• Joint pain

• Anal sacculitis

• Obstipation/constipation

• Hyperthyroidism

• Neoplasia

• Cognitive dysfunction

Urinary House Soiling

• Diseases causing polyuria (e.g., renal disease, hyperadrenocorticism, diabetes, pyometra)

• Increased urinary frequency (FLUTD, urolithiasis, idiopathic cystitis)

• Impaired bladder control (peripheral nerve disease, spinal cord disease, brain tumor, encephalitis, infection, degenerative brain disorders)

• Joint pain, disk disease

• Hyperthyroidism

• Neoplasia

• Anatomic problems

• Cognitive dysfunction

Behavioral Causes

Litterbox Aversion

• Aversive disorder (deodorant, ammonia)

• Inadequate cleaning

• Discomfort during elimination (FLUTD, constipation, diarrhea, arthritis)

• Unacceptable litter (texture, depth, odor, plastic liner)

• Unacceptable box (too small, sides too high, covered)

• Disciplined, medicated, or frightened in box

Location Aversion

• Too much traffic

• Traumatic/fearful experience in area

Other

• Location preference

• Surface preference

• Anxiety (owner absence, high cat density, moving, new furniture, inappropriate punishment, teasing, household changes, remodeling in home)

• Need for privacy (other pets, anything that makes box less accessible to cat)

Urine Marking

• Hormones

• Temperament

• Feline population density

• Indirect signaling from other cats (scent on visitor’s clothing)

• Changes in environment (new roommate, remodeling home, new furniture, and other novel items in home)

• Owner absence from home

• Lack of owner attention

• Inappropriate punishment

Incontinence, Fecal

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

• Diskospondylitis

• Neoplasia

• Degenerative myelopathy

• Congenital vertebral malformation

• Sacrococcygeal hypoplasia of Manx cats

• Sacral fracture

• Sacrococcygeal subluxation

• Lumbosacral instability

• Meningomyelocele

• Viral meningomyelitis

Peripheral Neuropathy

• Trauma

• Penetrating wounds

• Repair of perineal hernia

• Perineal urethrostomy

• Hypothyroidism

• Diabetes mellitus

• Dysautonomia

Incontinence, Urinary

Bladder Distended

Neurogenic

• Lower motor neuron disease (sacral [S1-S3] segments or peripheral nerves)

• Bladder easily expressed, dribbles urine

• Detrusor areflexia with sphincter areflexia

• Upper motor neuron disease

• Bladder difficult to express; may be associated with paresis, paralysis

• Detrusor areflexia with sphincter hypertonia

• Dysautonomia

Obstructive

• Reflex dyssynergia (functional obstruction)

• Mechanical obstruction (uroliths, tumors, strictures, granulomatous urethritis, urethral inflammation, prostatic disease, mucoid or crystalline plug [feline])

Bladder Not Distended

Dysuria/Pollakiuria Absent

• Urethral sphincter mechanism incompetence (middle-aged to older spayed or neutered dogs)

• Congenital (ectopic ureters, patent urachus)

Dysuria/Pollakiuria Present

• Detrusor hyperreflexia/instability (uroliths, urinary tract infection, urethral mass)

Infertility, Female

Normal Cycles

• Improper breeding management

• Infertile male

• Elevated diestrual progesterone

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

  • •
    Cystic follicles (ovulation failure)

Abnormal Cycles

Abnormal Estrus

Will Not Copulate

• Not in estrus

• Inexperience

• Partner preference

• Vaginal anomaly

• Hypothyroidism?

Prolonged Estrus

• Cystic follicles

• Ovarian neoplasia

• Exogenous estrogens

• Prolonged proestrus

Short Estrus

• Observation error

• Geriatric

• Split estrus

Abnormal Interestrual Interval

Prolonged Interval

• Photoperiod (queen)

• Pseudopregnant/pregnant (queen)

• Normal breed variation

• Glucocorticoids (bitch)

• Geriatric

• 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

• Ovarian neoplasia

• Premature ovarian failure

Infertility, 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

Abnormal Motility/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

Joint Swelling

• Trauma

• Degenerative joint disease

• Neoplasia

• Inflammatory joint disease—infectious

  • •
    Septic (bacterial)
  • •
    Fungal arthritis

    • •
      Blastomycosis
    • •
      Coccidioidomycosis
    • •
      Cryptococcosis
  • •
    Lyme borreliosis
  • •
    Rickettsial arthritis
  • •
    Leishmaniasis
  • •
    Anaplasmosis
  • •
    Mycoplasma
  • •
    Bacterial l form–associated arthritis (cats)
  • •
    Viral arthritis (calicivirus infection—kittens, canine distemper virus—dogs)
• Inflammatory joint disease—noninfectious

  • •
    Nonerosive

    • •
      Immune-mediated polyarthritis (idiopathic)
    • •
      SLE
    • •
      Breed-specific polyarthritis syndromes (Akita, Boxer, Weimaraners, Bernese Mountain Dog, German Shorthaired Pointer, Beagle, Shar-Pei)
    • •
      Lymphocytic/plasmacytic synovitis
    • •
      Drug reaction (e.g., trimethoprim-sulfadiazine in Doberman Pinschers)
    • •
      Chronic infection causing secondary immune-mediated polyarthritis (bacterial, ehrlichiosis, anaplasmosis, Rocky Mountain spotted fever, Lyme borreliosis, heartworm disease)
  • •
    Erosive

    • •
      Rheumatoid arthritis
    • •
      Erosive polyarthritis of Greyhounds
    • •
      Feline chronic progressive polyarthritis

Lameness

Orthopedic

Trauma

• Fracture

• Luxation, subluxation

• Toenail trauma

• Bone contusion

Infectious

• Osteomyelitis (bacterial, fungal)

• Bacterial cellulitis

• Septic arthritis

• Tick-borne polyarthritis

Degenerative

• Degenerative joint disease

• Cranial cruciate disease

• Hip dysplasia

• Elbow dysplasia

Developmental

• Patellar luxation

• Osteochondrosis

• Panosteitis

• Hypertrophic osteodystrophy

• Avascular necrosis of femoral head

• Nonunited anconeal process

• Bone cysts

• Radial agenesis

Metabolic

• Panosteitis

• Hypertrophic osteodystrophy (HOD)

• Diabetic neuropathy

Nutritional

• Vitamin D deficiency (rickets)

Neoplasia

• Osteosarcoma, synovial cell sarcoma, soft tissue sarcoma/carcinoma

• Multiple myeloma

• Metastatic to bone

Muscles

Trauma

• Contusion

• Strain

• Laceration

• Rupture

Inflammatory

• Canine idiopathic polymyositis

• Feline idiopathic polymyositis

• Dermatomyositis

Infectious

• Protozoal myositis

Tendons

Trauma

• Laceration

• Severance

• Avulsion

Ligaments

Trauma

• Rupture

• Tear

• Hyperextension

Lymphadenopathy (Lymph Node Enlargement)

Infiltrative Lymphadenopathies

Neoplastic

• Primary hemolymphatic (lymphoma, multiple myeloma, systemic mast cell disease, leukemias, malignant histiocytosis, lymphomatoid granulomatosis)

• Metastatic neoplasia (carcinomas, sarcomas, malignant melanoma, mast cell tumors)

Nonneoplastic

• Eosinophilic granuloma complex

• Nonneoplastic mast cell infiltration

Proliferative and Inflammatory Lymphadenopathies

Infectious

• Bacterial

  • •
    Localized bacterial infection
  • •
    Septicemia
  • •
    Systemic infection (e.g., Borrelia burgdorferi, Brucella canis, Yersinia pestis, Corynebacterium, Mycobacterium, Nocardia, Streptococcus, Actinomyces, Bartonella Ehrlichia spp.)
  • •
    Contagious streptococcal lymphadenopathy

• Parasitic (toxoplasmosis, demodicosis, babesiosis, cytauxzoonosis, hepatozoonosis, leishmaniasis, trypanosomiasis, Neospora caninum)

• Rickettsial (ehrlichiosis, Rocky Mountain spotted fever, anaplasmosis, salmon poisoning)

• Viral (FIV, FeLV, FIP, canine viral enteritis, infectious canine hepatitis)

• Fungal (blastomyosis, cryptococcosis, histoplasmosis, aspergillosis, coccidioidomycosis, phaeohyphomycosis, phycomycosis, sporotrichosis, others)

• Algal (protothecosis) Pneumocystis carinii

Noninfectious

• Immune-mediated disorders

  • •
    SLE
  • •
    Rheumatoid arthritis
  • •
    Immune-mediated polyarthritis
  • •
    Juvenile cellulitis

• Drug reactions

• Localized inflammation

• Postvaccinal

• Dermatopathic lymphadenopathy

• Idiopathic

  • •
    Distinctive peripheral lymph node hyperplasia
  • •
    Plexiform vascularization of lymph nodes

Melena

Ingested Blood

• Oral lesions

• Nasopharyngeal lesions

• Pulmonary lesions

• Diet

Parasitism

• Hookworms, protozoa

Neoplasia

• Adenocarcinoma

• Lymphoma

• Leiomyoma or leiomyosarcoma

• Mast cell tumor

• Gastrinoma

• Nasal or oral tumor

Upper Gastrointestinal Inflammation

• Acute gastritis

• Gastroduodenal ulceration/erosion

• Hemorrhagic gastroenteritis

• Inflammatory bowel disease

• Foreign body

• Esophagitis

Infection

• Campylobacter

• Clostridium perfringens

• Salmonella

• Parvovirus

• Neorickettsia helminthoeca (salmon poisoning)

• Histoplasma

• Pythium

• Helicobacter

Drugs

• NSAIDs

• Glucocorticoids

Miscellaneous

• Pancreatitis

• Liver failure

• Renal failure

• Hypoadrenocorticism

• GI ischemia (shock, volvulus, intussusception)

• Arteriovenous fistula

• Polyps

• Coagulopathies (thrombocytopenia, factor deficiencies, rodenticide toxicity, DIC)

Muscle Wasting

See Cachexia and Muscle Wasting.

Nasal Discharge

See Sneezing and Nasal Discharge.

Nystagmus

Peripheral Vestibular Disease

Horizontal nystagmus; fast phase toward normal side; no change with varying head position

• Otitis media/interna

• Feline idiopathic vestibular disease

• Canine geriatric vestibular disease

• Neoplasia

• Feline nasopharyngeal polyp in middle ear

• Granuloma

• Trauma (iatrogenic secondary to ear cleaning)

• Ototoxic drugs

• Neuropathy (hypothyroid, cranial nerve VIII disease)

• Congenital (German Shepherd, English Cocker Spaniel, Doberman Pinscher, Smooth-Haired Fox Terrier, Siamese, Burmese, Tonkinese)

Central Vestibular Disease

Horizontal, vertical, or rotary nystagmus; direction may change with varying head position

• Trauma/hemorrhage

• Infectious inflammatory disease

• Viral (canine distemper virus, FIP)

• Rickettsial (Rocky Mountain spotted fever, ehrlichiosis)

• Fungal (cryptococcosis)

• Toxoplasmosis

• Neosporosis

• Granulomatous meningoencephalitis

• Neoplasia

• Vascular infarct

• Thiamine deficiency

• Metronidazole toxicity

• Toxic (lead, hexachlorophene)

• Degenerative diseases (storage diseases, neuronopathies, demyelinating diseases)

• Hydrocephalus

• Anomaly (caudal occipital malformation syndrome in Cavalier King Charles Spaniels)

• Head trauma

Obesity

Causes

• Excessive feeding

• Malnutrition

• High-carbohydrate diet (especially cats)

• Lack of exercise

• Inactivity (indoor lifestyle, middle age)

• Neutering?

• Genetic predisposition

• Hypothyroidism

• Hyperadrenocorticism

• Hyperinsulinism

• Acromegaly

• Hypopituitarism

• Hypothalamic dysfunction

• Drugs (glucocorticoids, progestogens, phenobarbital, primidone)

Health Risks

• Degenerative joint disease

• Cruciate ligament disease

• Hip dysplasia

• Traumatic joint disease

• Intervertebral disk disease

• Dyspnea (Pickwickian syndrome)

• Heat intolerance

• Exercise intolerance

• Diabetes mellitus (insulin resistance)

• Hepatic lipidosis (cats)

• Pancreatitis

• Dystocia

• Urinary tract disease

• Skin fold dermatoses

• Increased anesthetic risk

Oliguria

See Anuria and Oliguria.

Pallor

Anemia

Regenerative Anemia

• Immune-mediated hemolytic anemia (extravascular, intravascular)

• Erythrocytic parasites (Bartonella, Babesia, Cytauxzoon spp.)

• Fragmentation (DIC, heartworm disease, hemangiosarcoma, vasculitis, hemolytic uremic syndrome, diabetes mellitus)

• Pyruvate kinase deficiency

• Phosphofructokinase deficiency

• Feline porphyria

• Copper toxicity

• Neonatal isoerythrolysis

• Oxidative injury (onions, acetaminophen, zinc, benzocaine, mothballs, phenazopyridine)

• Blood loss (external blood loss, blood loss to a body cavity, coagulopathies, endoparasites, GI blood loss)

Nonregenerative Anemia

• Anemia of chronic disease

• Anemia from renal failure

• FeLV

• Endocrine (mild anemia associated with hypoadrenocorticism, hypothyroidism)

• Myeloaplasia/aplastic anemia (FeLV infection, ehrlichiosis, trimethoprim-sulfa, estrogen toxicity, phenylbutazone, chemotherapy, chloramphenicol)

• Myelodysplasia

• Myeloproliferative and lymphoproliferative disorders

• Myelofibrosis

Shock

Cardiogenic

• Decreased ventricular function

  • •
    Dilated cardiomyopathy
  • •
    Myocarditis
  • •
    Myocardial infarction
• Compromised ventricular filling

  • •
    Hypertrophic cardiomyopathy
  • •
    Cardiac tamponade

• Severe endocardiosis

• Outflow obstruction

  • •
    Intracardiac tumors
  • •
    Aortic stenosis
  • •
    Hypertrophic obstructive cardiomyopathy
  • •
    Heartworm disease
  • •
    Thrombosis
  • •
    Severe arrhythmia

Noncardiogenic

• Trauma

• Hypovolemia

  • •
    Severe blood loss
  • •
    Dehydration
  • •
    Hypoadrenocorticism
• Disruptions in blood flow

  • •
    Sepsis and endotoxemia
  • •
    Hypotension

Panting

Differential Diagnosis of Panting

• •Elevated ambient temperature
• •Exercise-induced hyperthermia
• •Excessive/matted coat
• •Obesity
• •Fever
• •Pain
• •Anxiety/nervousness
• •Glucocorticoid therapy
• •Hyperadrenocorticism
• •Hyperthyroidism
• •Cardiac disease, tachyarrhythmia
• •Feline bronchial disease
• •Narcotic administration
• •Hypocalcemia
• •Pheochromocytoma
• •Brain disease

Papules and Pustules

• •Bacterial pyoderma (papules and pustules)
• •Demodicosis (papules and pustules)
• •Dermatophytosis (rare papules, uncommon pustules)
• •Sarcoptes mange (papules, no pustules)
• •Cheyletiellosis (rare papules, no pustules)
• •Otacariosis (rare papules, no pustules)
• •Trombiculosis (papules, rare pustules)
• •Hypersensitivity (papules, rare pustules)
• •Pemphigus (papules and pustules)
• •Early-stage neoplasia (papules, no pustules)

Paresis and Paralysis

Upper Motor Neuron

• Tetraparesis or hemiparesis

  • •
    Severe forebrain lesion
  • •
    Brain stem lesion
  • •
    First to fifth cervical (C1-C5) spinal lesion
• Paraparesis or rear limb monoparesis

  • •
    Third thoracic to third lumbar (T3-L3) spinal lesion

Lower Motor Neuron

• Tetraparesis

• Generalized lower motor neuron disease

  • •
    Flaccid paresis/paralysis

    • •
      Acute polyradiculoneuritis/“coonhound paralysis”
    • •
      Tick paralysis
    • •
      Botulism
    • •
      Myasthenia gravis
  • •
    Toxicants

    • •
      Coral snake
    • •
      Black widow spider
    • •
      Herbicides (2,4 D)
    • •
      Macadamia nuts
• Paraparesis

  • •
    Fourth lumbar to second sacral (L4-S2) spinal lesion
• Hemiparesis with lower motor neuron forelimb

  • •
    Sixth cervical to second thoracic (C6-T2) spinal lesion

• Aortic thromboembolism

• Degenerative myelopathy

• Monoparesis

• Peripheral nerve lesion

Petechiae and Ecchymoses

Thrombocytopenia

Increased Platelet Destruction

• Immune-mediated thrombocytopenia

• SLE

• Heartworm disease

Decreased Platelet Production

Bone Marrow Suppression

• Infectious disease (ehrlichiosis, babesiosis, Rocky Mountain spotted fever, leishmaniasis, FeLV, FIV)

• Neoplasia

• Drug reactions

• Myeloproliferative disease

• Virus-associated myelodysplasia

• Estrogen toxicity

Consumption of Platelets

• DIC

• Vasculitis

Sequestration of Platelets (Unlikely to Cause Clinical Signs)

• Splenomegaly

• Hepatomegaly

• Endotoxemia

Thrombopathia

Inherited

• Cocker Spaniel, Otterhound, Great Pyrenees, Bassett Hound, American Cocker Spaniel, cats

Acquired

• Drugs (aspirin, cephalothin, carprofen, hydroxyethyl starch)

• Uremia

• Liver disease

• Dysproteinemias

Von Willebrand Disease

• Lack of von Willebrand factor leads to impaired platelet adhesion.

Vascular Purpura

• Vasculitis secondary to infectious, inflammatory, immune-mediated, neoplasia, drug reaction, hyperadrenocorticism

Pollakiuria

See Stranguria, Dysuria, and Pollakiuria.

Polyphagia

Primary Polyphagia

• •Destruction of satiety center (mass lesion, trauma, infection/inflammation)
• •Psychogenic/gluttony
• •Stress
• •Introduction of more palatable diet

Secondary Polyphagia

• •Physiologically increased metabolic rate (cold temperature, pregnancy, lactation, growth, exercise)
• •Pathologically increased metabolic rate (hyperthyroidism, infection, neoplasia)
• •Decreased energy supply (diabetes mellitus, exocrine pancreatic insufficiency, infiltrative bowel disease, parasites, lymphangiectasia)
• •Decreased intake (low-calorie diet, hypoglycemia, megaesophagus)
• •Unknown (hyperadrenocorticism, portosystemic shunt/hepatoencephalopathy, sudden acquired retinal degeneration syndrome [SARDS])

Drug-induced Polyphagia

• •Glucocorticoids, phenobarbital, antihistamines, progestins, benzodiazepines, cyproheptadine, mirtazapine)

Polyuria and Polydipsia

• Renal insufficiency or failure

• Diabetes mellitus

• Hyperadrenocorticism (Cushing syndrome)

• Lower urinary tract disease

  • •
    Infection
  • •
    Urolithiasis
  • •
    Neoplasia
  • •
    Anatomic problem
  • •
    Neurologic problem

• Pyometra

• Hypercalcemia

• Hypoadrenocorticism (Addison disease)

• Pyelonephritis

• Hypokalemia

• Iatrogenic (corticosteroids, diuretics, anticonvulsants)

• Hyperthyroidism

• Hepatic insufficiency

• Postobstructive

• Diabetes insipidus

  • •
    Central
  • •
    Renal

• Psychogenic drinking

• Renal glycosuria

Preputial Discharge

Mucopurulent

• •Balanoposthitis
• •Prostatitis
• •Penile neoplasia
• •Foreign body

Serosanguinous

• •Benign prostatic hyperplasia
• •Balanoposthitis
• •Prostatitis
• •Urethral prolapse
• •Penile/urethral trauma
• •Penile/urethral uroliths
• •Penile neoplasia
• •Hemorrhagic diathesis
• •Foreign body

Pruritus

Allergy

• Flea allergy

• Atopic dermatitis

• Food allergy/intolerance

• Contact dermatitis

• Mosquito-bite hypersensitivity

• Eosinophilic plaque (cats)

Parasites

• Flea infestation

• Scabies

• Pediculosis (lice)

• Cheyletiellosis

• Chiggers

• Cutaneous larval migrans

• Demodicosis (often not pruritic)

• Otodectic acariasis

• Notoedres acariasis

Infectious Agents

• Pyoderma

• Malassezia dermatitis

• Dermatophytosis

Behavioral

• Acral lick dermatosis

• Psychogenic alopecia

Immune Mediated

• Pemphigus foliaceus

Miscellaneous

• Cornification defects

• Superficial necrolytic dermatitis

• Tail dock neuroma

• Rhabditic dermatitis

Ptyalism (Excessive Salivation)

Oral Cavity Disease

• Oral trauma (tooth fractures, mandibular fractures, maxillary fractures, temporomandibular joint [TMJ] luxation)

• Severe periodontal disease

• Oral masses (neoplasia, granuloma, eosinophilic granuloma)

• Abscesses

• Stomatitis (toxins, infections, immune-mediated disease, immunologic or nutritional deficiency)

• Glossitis (chemical or environmental irritants, viral infections, uremia, immune-mediated disease, tumors)

• Faucitis (cats)

• Mucocutaneous junction lesions

• Foreign body

• Developmental (severe brachygnathism, lip fold pyoderma)

• Conformational drooling

Oral Cavity Normal

• Drugs and toxins (bitter taste; insecticides such as organophosphates, pyrethrins, and d-limonene; caustic chemicals; poison toads and salamanders)

• Nausea

• Hepatic encephalopathy/portosystemic shunt

• Seizures

• Space-occupying lesions in pharynx

• Cranial nerve (CN) deficits (CN V: inability to close mouth; CN VII: inability to move lip; CNs X, XI, and XII: loss of gag lesion and inability to swallow)

• Neuromuscular (myasthenia gravis, temporal or masseter muscle atrophy, tetanus)

• Rabies virus

• Dysphagia

• Behavior (associated with food [Pavlovian], contentment/mood in cats when purring, pain)

• Salivary gland hypersecretion

Pulse Abnormalities

• •
  Hyperkinetic pulse

  • 1.
    Anemia
  • 2.
    Hyperthyroidism
  • 3.
    Increased sympathetic tone
  • 4.
    Bradyarrhythmias
  • 5.
    Aortic insufficiency
  • 6.
    Patent ductus arteriosus
  • 7.
    Pregnancy
  • 8.
    Aorticopulmonary window
  • 9.
    Arteriovenous fistula/anastomosis
• •
  Hypokinetic pulse

  • 1.
    Hypovolemia
  • 2.
    Reduced systolic function
  • 3.
    Aortic/subaortic stenosis
  • 4.
    Dynamic left ventricular outflow tract obstruction
• •
  Decrease in pulse volume with inspiration

  • 1.
    Pericardial effusion with cardiac tamponade
  • 2.
    Exaggerated variation in intrapleural pressure (airway obstruction)
• •
  Pulse deficits

  • 1.
    Atrial fibrillation
  • 2.
    Atrial/supraventricular premature complexes
  • 3.
    Ventricular premature complexes
  • 4.
    Pulsus alternans (alternating normal pulse and pulse deficits with myocardial failure)
• •
  Irregular pulse rhythm

  • 1.
    Sinus arrhythmia (slow)
  • 2.
    Atrial fibrillation
  • 3.
    Atrial/supraventricular premature complexes (rapid)
  • 4.
    Ventricular premature complexes (rapid)
  • 5.
    Second-degree atrioventricular block (slow)
• •
  Regional pulse variation

  • 1.
    Arterial thromboembolism

Regurgitation

Esophageal Disease

• Megaesophagus (primary or secondary)

• Esophagitis

• Mechanical obstruction (foreign body, vascular ring anomaly, stricture)

Alimentary Disorders

• Pyloric outflow obstruction

• Gastric dilatation/volvulus

• Hiatal hernia

Neuropathies

• Peripheral neuropathy (polyradiculitis, polyneuritis, lead poisoning, giant cell axonal neuropathy)

• Central nervous system (brain stem lesion, neoplastic, traumatic, distemper)

• Dysautonomia

Neuromuscular Junction Abnormalities

• Myasthenia gravis (focal or generalized)

• Tetanus

• Botulism

• Acetylcholinesterase toxicity

Immune-Mediated Disorders

• SLE

• Polymyositis

• Dermatomyositis

Endocrine Disease

• Hypothyroidism

• Hypoadrenocorticism

Infectious

• Spirocercosis

• Pythium insidiosum

Restlessness

Causes of Restless Behaviors in Dogs and Cats

Normal behavior

• •Discomfort from pollakiuria or tenesmus
• •Periparturient
• •Estrous
• •Pseudopregnancy

Emotional distress

• •Fear/phobia
• •Stress from altered environment or blindness
• •Pending natural calamity (e.g., earthquake)
• •Anxiety

Physiologic distress

• •Shock
• •Transfusion reaction
• •Anaphylaxis
• •Iatrogenic overhydration
• •Dyspnea
• •Pheochromocytoma
• •Overheating
• •Fever
• •Pruritus

Intoxication

• •Drug induced (antipsychotics, tricyclic antidepressants, selective serotonin reuptake inhibitors, methylxanthines, sympathomimetics, prostaglandins, opioids, metoclopramide, antihistamines [cats], digoxin, salicylates, benzodiazepines [excitatory phase], drug or anesthesia induced dysphoria)
• •Other toxic substances (metaldehyde, pyrethrins, strychnine, nicotine, organophosphates/carbamates, recreational drugs [amphetamine, cocaine], mycotoxins)

Altered mentation/encephalopathy

• •Primary central nervous system (CNS) disease (epileptic aura [preictal], tumors, inflammation, rabies/pseudorabies, geriatric cognitive dysfunction)
• •Metabolic encephalopathies (hepatic encephalopathy, hypoglycemia, hypocalcemia)

Increased metabolic rate

• •Hyperthyroidism (iatrogenic or spontaneous)

Reverse Sneezing

• •Loud inspiratory noise, occurs in paroxysms; initiated by nasopharyngeal irritation
• •Purpose is to move secretions and foreign material into the oropharynx to be swallowed
• •Causes include excitement, foreign bodies, nasal mites (Pneumonyussus caninum), viral infections, and epiglottic entrapment of the soft palate
• •Often idiopathic, nonprogressive, and common in small dogs and cats

Scaling and Crusting

Bacterial

• Superficial folliculitis

• Deep pyoderma

• Mucocutaneous pyoderma

• Pyotraumatic dermatitis

Fungal

• Dermatophytosis

• Malassezia dermatitis

• Deep fungal infection (e.g., blastomycosis, cryptococcosis)

Parasitic

• Fleas

• Scabies

• Demodecosis

• Cheyletiellosis

• Notoedric mange

• Pediculosis

Protozoal

• Leishmaniasis

Viral

• FeLV

Allergic

• Atopic dermatitis

• Food hypersensitivity

• Flea-bite hypersensitivity

• Military dermatitis

Endocrine and Metabolic

• Hyperadrenocorticism

• Hypothyroidism

• Necrolytic migratory erythema

Immune Mediated

• Pemphigus foliaceus

• DLE

• Erythema multiforme

Congenital and Hereditary

• Primary seborrhea

• Ichthyosis

• Schnauzer comedo syndrome

• Familial canine dermatomyositis

Keratinization Defects

• Secondary seborrhea

• Vitamin A–responsive dermatosis

• Ear margin dermatosis

Environmental

• Solar dermatitis

Nutritional

• Zinc-responsive dermatosis

• Fatty acid deficiency

Other

• Cutaneous lymphoma

• Sebaceous adenitis

• Otitis externa

Seizure

Extracranial Causes

• Toxins (e.g., strychnine, chlorinated hydrocarbons, organophosphates, carbamates, lead, ethylene glycol, metaldehyde)

• Metabolic disease (e.g., hepatic encephalopathy, hypoglycemia, hypocalcemia)

• Hepatic disease

• Electrolyte disturbances (e.g., hypernatremia)

• Severe uremia

• Hyperlipoproteinemia

• Hyperviscosity (multiple myeloma, polycythemia)

• Hyperosmolality (diabetes mellitus)

• Heat stroke

• Hypertension

• Hyperthyroidism (cats)

• Hypothyroidism (dogs)

Intracranial Causes

See Part Two, Section XI: Differential Diagnosis for Inflammatory Disease of the Nervous System.

• Infectious disease

• Neoplasia (primary brain tumor, lymphoma, metastatic tumors)

• Granulomatous meningoencephalitis

• Hemorrhage/infarct (renal failure, hypothyroidism, hyperthyroidism, hypertension, septic emboli, neoplasia, coagulopathies, heartworm disease, vasculitis)

• Congenital malformations (lissencephaly, hydrocephalus)

• Necrotizing meningoencephalitis, necrotizing leukoencephalitis

• Degenerative diseases (metabolic storage diseases, leukodystrophies, hypomyelination disorders, spongy disorders)

Sneezing and Nasal Discharge

Nasal and Upper Respiratory Disease

Infectious

• Viral: feline herpesvirus, calicivirus, canine distemper virus

• Bacterial: Mycoplasma spp., Bordetella bronchiseptica

• Fungal: Aspergillus, Cryptococcus, Rhinosporidium, Penicillium spp.

• Parasitic: Pneumonyssus caninum (nasal mite), Eucoleus boehmi (formerly Capillaria spp.), Cuterebra spp., Linguatula spp.

Inflammatory

• Allergic rhinitis

• Lymphocytic-plasmacytic rhinitis

• Acquired nasopharyngeal stenosis

• Nasopharyngeal polyps

• Polypoid rhinitis

Neoplasia

• Adenocarcinoma, squamous cell carcinoma

• Fibrosarcoma, osteosarcoma, chondrosarcoma

• Lymphoma, transmissible venereal tumor, neuroendocrine carcinoma

Congenital

• Cleft palate

• Ciliary dyskinesia

• Nasopharyngeal stenosis

• Choanal atresia

Dental Disease

• Tooth root abscess

• Oronasal fistula

Systemic Disease

Infectious

• Canine distemper virus

• Canine infectious tracheobronchitis

• Pneumonia

Hypertension

• Hyperthyroidism

• Hyperadrenocorticism

• Renal disease

• Pheochromocytoma

• Hypothyroidism

• Acromegaly

• Polycythemia

• Diabetes mellitus

• Overhydration

Coagulopathies

• Thrombocytopenia

• Rocky Mountain spotted fever

• Thrombocytopathia

• von Willebrand disease

• Factor deficiencies

• Congenital (hemophilia A, B, others)

• Acquired (vitamin K rodenticide toxicity, DIC, hepatic failure)

Vasculitis

• Toxic

• Inflammatory

• Immune mediated (SLE)

• Neoplastic

• Infectious (ehrlichiosis, FIP, Rocky Mountain spotted fever, leishmaniasis)

Hyperviscosity

• Multiple myeloma

• Lymphoma

• IgM (Waldenstrom) macroglobulinemia

• Chronic lymphocytic leukemia

• Ehrlichiosis

• Amyloidosis

• Plasma cell leukemia

• FIP (rare)

Stertor and Stridor

Stertor

• Snoring or snorting associated with partial nasal or nasopharyngeal obstruction

Intranasal Disorders

• Congenital deformities

• Masses

• Exudates

• Clotted blood

Pharyngeal Disease

• Brachycephalic airway syndrome

• Elongated soft palate

• Nasopharyngeal polyp

• Foreign body

• Neoplasia

• Abscess

• Granuloma

• Extraluminal mass

Stridor

High-pitched wheeze caused by air turbulence in upper airway associated with laryngeal disease or narrowing of extrathoracic trachea

Laryngeal Disease

• Neoplasia

• Polyps (nasopharyngeal)

• Laryngeal paralysis

• Laryngeal trauma

• Foreign body

• Acute laryngitis/obstructive laryngitis

• Brachycephalic syndrome

• Rhinitis

• Coagulopathy

Extrathoracic Tracheal Disease

• Neoplasia

• Foreign body

• Extrathoracic collapsing trachea

• Extraluminal mass

Stranguria, Dysuria, and Pollakiuria

Stranguria/Pollakiuria

Small Bladder

• Cystitis

  • •
    Infectious agents
  • •
    Idiopathic cystitis (cats)
  • •
    Chemically induced cystitis (cyclophosphamide)
  • •
    Polypoid cystitis

• Detrusor hyperspasticity

• Urethritis

• Urethral mass

Large Bladder

• Lower urinary tract obstruction

  • •
    Functional
  • •
    Mechanical

Urinary Retention

Easy Catheterization

Normal Neurologic Examination

• Cystic calculi or mass

• Detrusor areflexia from overdistension

• Reflex dyssynergia

Abnormal Neurologic Examination

• Detrusor areflexia with sphincter areflexia (lower motor neuron)

• Detrusor areflexia with sphincter hypertonia (upper motor neuron)

• Dysautonomia

Difficult Catheterization

• Urethral spasm

• Urethral calculi

• Urethral stricture

• Urethral neoplasia

• Transitional cell carcinoma

• Granulomatous urethritis

• Urethral inflammation

• Prostatic disease

• Mucoid or crystalline plug (cats)

Stomatitis

• Infectious disease

  • •
    FIV
  • •
    FeLV
  • •
    Feline syncytium-forming virus
  • •
    Feline calicivirus
  • •
    Feline herpesvirus
  • •
    FIP
  • •
    Bartonellosis
  • •
    Canine distemper virus
  • •
    Feline panleukopenia virus
  • •
    Candidiasis

• Immunosuppressive disease

• Feline eosinophilic granuloma complex

• Idiopathic feline chronic gingivitis/stomatitis

• Immune-mediated disease

  • •
    SLE
  • •
    Bullous (pemphigus) disease
  • •
    Idiopathic vasculitis
  • •
    Toxic epidermal necrolysis
  • •
    Ulcerative gingivitis/stomatitis of Maltese Terriers
  • •
    Sjӧgren-like syndrome

• Uremic stomatitis

• Radiation-induced

Stunted Growth

Small Stature and Poor Body Condition

• •Nutritional (poor quality feed, underfeeding)
• •Gastrointestinal (parasitism, food intolerance/allergy, inflammatory bowel disease, exocrine pancreatic insufficiency, obstruction)
• •Esophageal disease (congenital myasthenia gravis, megaesophagus, vascular ring anomaly most commonly persistent right aortic arch)
• •Cardiac (dog: most commonly subaortic stenosis, patent ductus arteriosus, pulmonic stenosis) (cat: most commonly ventricular septal defect, atrioventricular valve dysplasia)
• •Systemic disease (metabolic/infectious: kidney disease, liver disease like portal systemic shunt, glycogen storage disease, respiratory infections like bacterial pneumonia, gastrointestinal infections)
• •Endocrine (diabetes mellitus, hypoadrenocorticism, diabetes insipidus, juvenile hypoparathyroidism)

Small Stature and Good Body Condition

• •Bone growth (osteochondrodystrophy: disproportionate dwarfism)
• •
  Endocrine

  • 1.
    Disproportionate dwarfism: congenital hypothyroidism
  • 2.
    Proportionate dwarfism: hyposomatotropism (growth hormone deficiency), hyperadrenocorticism (rare)

Stupor and Coma

Increased Intracranial Pressure

• Encephalitis

• Meningitis

• Neoplasia

• Granulomas

• Abscess

• Vascular events (hemorrhage, embolism, ischemia)

• Trauma

• Underlying metabolic injury (e.g., hypertension)

• Developmental (hydrocephalus, storage diseases)

Systemic Infections

• Rabies

• FIP

• Canine distemper

• Fungal

• Parasitic

Cerebral Edema

• Vasogenic (brain masses that lead to breakdown of blood–brain barrier)

• Cytotoxic (hypoxia, neuroglycopenia)

• Interstitial (hydrocephalus)

Herniation of Brain Tissue

• Caudal transtentorial herniation

• Foramen magnum herniation

Extracranial Causes

• Hypoglycemia

• Hypernatremia

• Hyponatremia

• Diabetic ketoacidosis

• Uremic encephalopathy

• Severe hypothyroidism (myxedema coma)

• Heat stroke

• Toxins

• Hepatic disease

• Hyperadrenocorticism

• Erythrocytosis

• Hyperglobulinemia

Syncope

Normal Cerebral Perfusion

• Severe hypoxemia

• Hypoglycemia

Cerebral Hypoperfusion

Normotension

• Cerebrovascular disease

• Cerebral vasoconstriction

Systemic Hypotension

Decreased Cardiac Output

Loss of preload

• Cardiac tamponade, atrial ball thrombi, atrial myxoma, atrioventricular (AV) valve stenosis, hypovolemia, diuretics

Obstruction to flow

• Aortic and subaortic stenosis, pulmonic stenosis, pulmonary hypertension, pulmonary thromboembolism, outflow tract tumors, myocardial infarction, hypertrophic and restrictive cardiomyopathy, systolic anterior motion of mitral valve, infundibular stenosis, heartworm disease, masses obstructing flow

Arrhythmias

• Bradyarrhythmias: sick sinus syndrome, third-degree AV block, persistent atrial standstill, β-blockers, calcium channel blockers

• Tachyarrhythmias: atrial fibrillation, atrial tachycardia, AV reentrant tachycardia, ventricular tachycardia, drug-induced proarrhythmia, torsades de pointes

Loss of vascular resistance

• Drug therapy: angiotensin-converting enzyme (ACE) inhibitors, β-blockers, calcium channel blockers, hydralazine, nitrates, phenothiazines

• Reflex syncope (neurally mediated): orthostatic, postexertion, micturition, defecation, cough, emotional distress, pain, carotid sinus hypersensitivity

• Autonomic nervous system disease: primary or secondary (diabetes mellitus, paraneoplastic, chronic renal failure, autoimmune disease, amyloidosis)

• Cyanotic heart disease (tetralogy of Fallot, reversed shunt)

Tachycardia, Sinus

• Anxiety/fear

• Excitement

• Exercise pain

• Hyperthyroidism

• Heart failure

• Hyperthermia/fever

• Anemia

• Hypoxia

• Shock

• Hypotension

• Sepsis

• Drugs (anticholinergics, sympathomimetics)

• Toxicity (e.g., chocolate, amphetamines, theophylline)

• Electric shock

• Any cause of high sympathetic tone

Tenesmus and Dyschezia

Colonic or Rectal Obstruction

• Constipation

• Pelvic fracture

• Rectal neoplasia

• Anal sac neoplasia

• Extraluminal neoplasia

• Prostatomegaly

• Perineal hernia

• Pelvic canal mass

• Rectal granuloma

• Rectal foreign body

• Rectal stricture

• Perianal gland tumors

• Pseudocoprostasis

Perineal Inflammation or Pain

• Anal sacculitis

• Perianal fistula

• Perianal abscess/abscessed anal sac

Rectal Inflammation or Pain

• Rectal tumor/polyp

• Proctitis

• Histoplasmosis

• Pythiosis

Colonic Inflammation

• Idiopathic colitis

• Bacteria

• Fungal

• Parasites

• Dietary indiscretion

• Inflammatory bowel disease

• Neoplasia

Tremor

Physiologic Tremor

• Hypothermia (shiver)

• Heavy exercise/exhaustion

Pathologic Tremor

• Metabolic disorders (renal disease, hypoglycemia, hypocalcemia, hypoadrenocorticism)

• Intracranial infectious disease (Neospora caninum, cerebellar hypoplasia secondary to intrauterine panleukopenia infection)

• Intracranial disease (fibrinoid leukodystrophy, neuraxonal dystrophy, Labrador Retriever axonopathy, spongiform encephalopathy, neuronal abiotrophies, subacute necrotizing encephalopathy, lysosomal storage diseases)

• Hind end tremor (intervertebral disk herniation, tumors, diskospondylitis, nerve root compression, peripheral neuropathies)

• Corticoid-responsive tremor syndrome (formerly “white shaker disease”)

• Myasthenia gravis

• Cerebellar malformation

• Hypomyelination

• Spongy degeneration

• Tremorgenic toxins (mycotoxins penitrem A and roquefortine produced by Penicillium spp. growing on spoiled foods; metaldehyde, hexachlorophene, bromethalin, organophosphates, carbamates, pyrethroids, xanthines, macadamia nuts, strychnine)

• Idiopathic head tremor in Doberman Pinschers and Bulldogs

• Idiopathic tremor of hind legs of geriatric dogs

Urine, Discolored

Red, Pink, Red-Brown, Red-Orange, or Orange

• Hematuria

• Hemoglobinuria

• Myoglobinuria

• Porphyrinuria

• Pyuria

Orange-Yellow

• Highly concentrated urine

• Urobilin

• Bilirubin

Yellow-Brown or Green-Brown

• Bile pigments

Brown to Black

• Melanin

• Methemoglobin

• Myoglobin

• Bile pigments

Brown

• Methemoglobin

• Melanin

Colorless

• Dilute urine

Milky White

• Lipid

• Pyuria

• Crystals

Pale Yellow

• Normal

• Dilute urine

Urticaria/Angioedema

Immediate Hypersensitivity Reaction

• Insect bites/stings

• Food

• Drugs/vaccines

• Airborne allergens (atopy)

Nonimmunologic Stimulus by Irritant

• Weeds

• Insects

• Physical stimuli (cold, heat, sunlight)

• Psychogenic stimuli

Vision Loss, Sudden

See Blindness.

Vomiting

Gastric Disease

• Gastritis

• Parasites

• Foreign body

• Obstruction

• Ulceration

• Neoplasia

• Dilatation/volvulus

• Helicobacter infection

• Gastric ulcer

• Hiatal hernia

• Motility disorders

• Pyloric stenosis

• Gastric antral mucosal hypertrophy

Small Intestinal Disease

• Parasites

• Inflammatory bowel disease

• Foreign body

• Bacterial overgrowth/enteritis

• Hemorrhagic gastroenteritis

• Neoplasia

• Viral enteritis (parvovirus, canine distemper virus)

• Intussusception

• Nonneoplastic infiltrative disease (e.g., pythiosis)

Large Intestinal Disease

• Colitis

• Obstipation

• Parasites

Dietary

• Indiscretion

• Intolerance

• Allergy

Drugs

• Cancer chemotherapeutic agents

• Antibiotics (especially erythromycin, tetracycline)

• NSAIDs

• Cardiac glycosides

• Apomorphine

• Xylazine

• Penicillamine

Extraalimentary Tract Disease

• Peritonitis

• Pancreatitis

• Hepatobiliary disease

• Neoplasia

• Uremia

• Diabetes mellitus/ketoacidosis

• Hypercalcemia

• Hyperthyroidism

• Hypoadrenocorticism

• Hepatic disease

• Hepatic encephalopathy

• Septicemia/endotoxemia

• Pyometra

• Acid–base disorders

• Electrolyte disorders

• Hypertriglyceridemia

• Gastrinoma (Zollinger–Ellison syndrome)

• Mastocytosis

• Motion sickness

Intoxicants

Numerous inorganic, organic, and plant toxins can cause GI irritation and vomiting.

Neurologic Disease

• Epilepsy, tumor, meningitis, increased intracranial pressure, dysautonomia

Vulvar Discharge

Serosanguinous Vaginal Discharge

Intact

• •Physiologic estrogen influence (proestrus)
• •Prolonged estrogen duration (ovarian neoplasia, cystic ovarian follicles, failure to ovulate, exogenous estrogen, portosystemic shunt, pituitary hypofunction)
• •Absence of estrogen influence (endometriosis, neoplasia of urogenital tract, subinvolution of placental sites, trauma, hemorrhagic diathesis, vaginal foreign body)

After ovariohysterectomy (OVH)

• •Estrogen influence (remnant ovarian syndrome, exogenous estrogen)
• •Absence of estrogen influence (stump endometritis secondary to presence of remnant ovarian syndrome with progesterone influence, uterine stump hemorrhage post-OVH, neoplasia of urogenital tract, trauma, hemorrhagic diathesis, vaginal foreign body)

Mucopurulent Vaginal Discharge

Intact

• •Physiologic (onset of diestrus, pregnancy [clear mucus])
• •Pathologic (endometritis post estrum or postpartum, abortion, vestibulitis/vaginitis, neoplasia, vaginal foreign body)

After ovariohysterectomy

• •Vaginitis, stump endometritis secondary to presence of remnant ovarian syndrome with progesterone influence, hypersecretion of vaginal mucosa, neoplasia, vaginal foreign body)

Weakness

• Very nonspecific clinical sign of disease

• Metabolic disease

• Inflammation

  • •
    Infectious disease (bacterial, viral, fungal, rickettsial, protozoal, parasitic)
  • •
    Immune-mediated disease

• Fever

• Electrolyte disorders

  • •
    Hypokalemia, hyperkalemia, hyponatremia, hypernatremia, hypocalcemia, hypomagnesemia

• Acid–base disorders

• Abdominal effusion

• Anemia

• Poor oxygen delivery

• Endocrine disease

  • •
    Diabetes mellitus, hypothyroidism, hypoadrenocorticism, hyperadrenocorticism, hypoglycemia, hyperparathyroidism, hypoparathyroidism, pheochromocytoma

• Cardiovascular disease

• Hypotension, hypertension

• Respiratory disease

• Skeletal disease

• Neuromuscular disease

  • •
    Brain disease (encephalitis, cerebrovascular accidents, space-occupying lesions, vestibular disease, idiopathic epilepsy)
  • •
    Spinal cord diseases
  • •
    Neuropathies (e.g., polyradiculoneuritis, myasthenia gravis, developmental disorders, toxoplasmosis, neosporosis)

• Neoplasia

• Cachexia

• Physical and psychologic stress

• Malnutrition

• Drugs

  • •
    Anticonvulsants, antihistamines, glucocorticoids, tranquilizers, narcotics, cardiac drugs

• Toxins

• Pain

Weight Gain

See Obesity.

Weight Loss

See Cachexia and Muscle Wasting.