Ornithine Transcarbamylase Deficiency: If at First You Do Not Diagnose, Try and Try Again

Table 1

Differential diagnosis of altered mental status.

Origin of AMS	Differential diagnosis
Infection	Urinary tract infection, pneumonia, bacteremia, meningitis, encephalitis, brain abscess, neurosyphilis, fever
Withdrawal	Alcohol, sedative-hypnotic drugs, barbiturates, benzodiazepines
Acute metabolic condition	Acid-base disturbance, electrolyte imbalance, liver or renal failure
Trauma	Head injury, surgery, burns, heat stroke, hypothermia
Central nervous system pathology	Subdural hematoma, epidural hematoma, subarachnoid hemorrhage, hydrocephalus, seizure, stroke, tumor, demyelinating lesion, transient ischemic attack
Hypoxia or cardiopulmonary condition	Hypoxemia, hypotension or shock, arrhythmia, anemia, carbon monoxide poisoning, methemoglobinemia
Vitamin deficiency	Thiamine (Wernicke encephalopathy), niacin, vitamin B12
Endocrinopathy	Hyperadrenocorticism, hypoadrenocorticism, hyperglycemia, hypoglycemia, hyperthyroidism, hypothyroidism, hypercalcemia
Acute vascular condition	Hypertensive encephalopathy, stroke, arrhythmia, shock, thrombotic thrombocytopenic purpura, mesenteric ischemia
Toxin or drug toxicity	Sedatives, narcotics, anticholinergics, antipsychotics, neuroleptic malignant syndrome, serotonin syndrome, illicit drugs
Heavy metal poisoning	Lead, arsenic, manganese, mercury, thallium