• Altered mental status

Intracranial causes

• Anoxic brain injury or head trauma
• Ischemic stroke or intracerebral hemorrhage
• Subarachnoid hemorrhage
• Meningitis or encephalitis
• Brainstem hemorrhage, infarct, or mass
• Mass lesion causing brainstem compression
• Subdural hematoma
• Seizure

Metabolic causes

• Hypoglycemia
• Diabetic ketoacidosis
• Hyperglycemic hyperosmolar state
• Drugs, eg, alcohol, opioids, sedatives, antidepressants, salicylates
• Uremic or hepatic encephalopathy
• Hypernatremia or hyponatremia
• Hypercalcemia
• Hypothermia
• Heat stroke
• Myxedema
• Carbon monoxide poisoning