DDx - 1. Metabolic - Hypoglycemia, hyperglycemia, hypoxia, hypercapnia, hypo/ hyper -natremia, hypo/hyper -kalemia, hypo/hyper -magnesemia, uremia, hepatic encephalopathy, febrile, heat stroke, hyperosmolar, acidosis, hyper/hypo-calcemia. Thiamine deficiency (Wernicke's encephalopathy); 2. Infectious - meningitis, encephalitis, sepsis -metabolic alkalosis, pneumonia, aspiration 3. Endocrine - hyper/ hypo -thyroidism, DKA, hyperosmotic nonketotic coma, Cushing's, Addison's; 4. Meds - Tagamet, Digoxin, Lidocaine, steroids, antidepressants (TCAs), sedatives, analgesics, medication overdose; 5. Neuro/CNS - head trauma (subdural hematoma, epidural hematoma..), brain cancer, brain mass, seizures, post ictal, CVA, increased ICP, SAH 6. Psych - dementia, sundowning, ICU psychosis, Alzheimer's, psychosis, schizophrenia, major depression, delerium 7. Withdrawl - ETOH, DTs, sedatives, hypnotics 8. Toxins - ETOH, metabolic acidosis (ASA, Methanol, Paraldehyde, Ethylene Glycol), lead, CO, Illegal drugs (crack, narcotics, amphetamines, PCP...) 9.Others - MI, hypotension, PE, hypertenisve encephalopathy