AEIOU-TIPS — Altered mental status differential
Pre-op altered or PACU delirium workup
Mnemonic device
AEIOU-TIPS
Mapping
A — Alcohol / abuse
Intoxication or withdrawal (delirium tremens 48-96 h after last drink)
E — Endocrine / Electrolytes
Hypo/hyperglycemia, Na/K/Ca derangement, thyroid storm, adrenal
I — Infection
Sepsis, meningitis, UTI in elderly
O — Overdose / Oxygen
Drug effect (esp opioid, benzo, anticholinergic), hypoxemia, CO
U — Uremia
Renal failure → uremic encephalopathy; also hepatic failure
T — Trauma / Temperature
Head injury, hypo/hyperthermia, hemorrhagic stroke
I — Insulin
Hypoglycemia (often missed) — fingerstick early
P — Psychiatric / Poisoning
Acute psychosis, ingestion, serotonin syndrome, NMS
S — Stroke / Seizure / Shock
CVA, post-ictal, hypoperfusion (cardiogenic, septic)
Clinical note: Order fingerstick glucose + ABG + electrolytes + tox screen FIRST in unexpected AMS. Don't fixate on one cause — they often coexist (elderly hip fracture: hypoxia + UTI + hypovolemia + opioid).