Table 2.

Conditions That Look Like or Cause Delirium^a

General Cause	Specific Cause
Vascular	Cerebral arteriosclerosis, circulatory collapse (shock), emboli from atrial fibrillation, patent foramen ovale, endocarditic valve, hypertensive encephalopathy, hyperviscosity syndrome, intracranial hemorrhage or thrombosis, polyarteritis nodosa, sarcoid, systemic lupus, erythematosus, thrombotic thrombocytopenic purpura
Infectious	Bacterial or viral meningitis, Behcet's syndrome, brain/epidural/subdural abscess, encephalitis, fungal meningitis (Cryptococcal, Cocidioidal, Histoplasma), general paresis, human immunodeficiency virus, Lyme disease, malaria, mumps, parasitic (toxoplasma, trichinosis, cysticercosis, echinococcosis), typhoid fever, sepsis
Neoplastic	Carcinomatous meningitis, paraneoplastic syndromes, space-occupying lesions (such as gliomas, meningiomas, abcesses)
Degenerative	Senile and presentile dementias (such as Alzheimer's or Pick's dementia, Creutzfeldt-Jakob disease, Huntington's chorea, Wilson's disease)
Intoxication	Chronic intoxication or withdrawal effect of sedative-hypnotic drugs (such as anticholinergics, anticonvulsants, bromides), carbon monoxide from burn inhalation, dissociative anesthetics, opiates, tranquilizers
Congenital	Aneurysm, complex partial status epilepticus, epilepsy, postictal states
Traumatic	Contusion, fat emboli syndrome, heat stroke, laceration, postoperative trauma, subdural and epidural hematomas
Intraventricular	Normal pressure hydrocephalous
Vitamin deficiency	Deficiencies of B12 (pernicious anemia), niacin (pellagra), and thiamine (Wernicke-Korsakoff syndrome)
Endocrine-metabolic	Carcinoid, Cushing's/Addison's syndrome, diabetic coma and shock, hepatic or renal failure, hyperthyroidism, hypoglycemia, myxedema, paraneoplastic syndromes, parathyroid dysfunction, porphyria, sleep apnea, severe electrolyte or acid/base disturbance, uremia, Whipple's syndrome
Metals	Heavy metals (eg, lead, manganese, mercury), other toxins
Anoxia	Hypoxia and anoxia secondary to pulmonary or cardiac failure, anemia, anesthesia
Depression-other	Catatonia, depressive pseudodementia, hysteria

^aAdapted with permission from Cassem et al.¹²