Altered Mental Status - DDx & Management

Can break it down into large categories:

1. Primary neurologic (Stroke, Seizure, Bleed)
2. Systemic Disease: Cardiovascular (Hypotension, low cardiac output), Pulmonary (Hypoxia), Renal (Uremia, Hypo/Hypernatremia, Hypercalcemia), Liver (Hepatic encephalopathy), Endocrine (hypoglycemia, thyroid dysfunction)
3. Infection: either primary CNS (meningitis/encephalitis, or systemic infection (anything - PNA, UTIs, esp in the elderly)
4. Drug Intoxication or Withdrawal: Opiates, BZDs, illicit drugs, EtOH intoxication or withdrawal
5. Psychiatric - dx of exclusion.

If you are like me, you can memorize the mnemonic MOVE STUPID for altered mental status

• Metabolic (Hypo/hypernatremia, Hypercalcemia)
• Oxygen (Hypoxia)
• Vascular (CVA, Bleed, MI, CHF)
• Endocrine (Hypoglycemia, Thyroid)
• Seizure (postictal state)
• Uremia
• Psychogenic
• Infection
• Drugs - intoxication or withdrawal

This is a situation where actually the mnemonic can be helpful, since it provides a good starting ddx.  Based on this ddx, you can tailor your workup:

• Thorough H+P, especially meds
• Full set of labs including CBC, electrolytes, and LFTs
• ABG can be helpful
• Urinalysis, Urine tox screen
• Thyroid function tests
• Consider head CT
• Consider blood cultures depending on scenario
• Consider lumbar puncture if suspicion for infection, or if other workup negative

(Chanu Rhee MD, 8/26/10)