AEIOU-TIPS
Causes of Altered Mental Status
10 categories to work through when the patient is confused.
Clinicians lean on this acronym when a confused patient lands in the office or ED and the differential needs a structure, fast. AEIOU-TIPS — Alcohol, Endocrine/Electrolytes, Insulin (hypo/hyperglycemia), Oxygen/Opioids, Uremia, Trauma/Toxins, Infection, Psychiatric, Stroke/Seizure — covers nearly every cause of altered mental status the AANP exam will throw at you. The point is comprehensiveness; missing one category is how diagnoses get missed in the real world. Run all ten on every confused patient until the workup narrows the list, and pick the answer choice that pairs the right letter to the right vignette finding.
- AAlcoholIntoxication, withdrawal, Wernicke encephalopathy (thiamine deficiency).
- EEpilepsy / Electrolytes / EncephalopathyPost-ictal; Na/Ca/glucose derangements; hepatic or uremic encephalopathy.
- IInsulinHypo- or hyperglycemia. Fingerstick is step one.
- OOpiates / OverdosePinpoint pupils + respiratory depression → narcan.
- UUremiaBUN >100 can cause encephalopathy; asterixis clues you in.
- TTrauma / TemperatureTBI (hidden subdural in elderly); hyperthermia or hypothermia.
- IInfectionSepsis, meningitis, encephalitis, UTI (esp. in the elderly).
- PPsychiatric / PoisoningAcute psychosis; CO, salicylate, or anticholinergic ingestion.
- SStroke / Shock / Space-occupying lesionCVA, hypoperfusion, tumor, or abscess.
Clinical Context
Broad differential for altered mental status. Work through each category systematically — the workup usually starts with fingerstick glucose, vitals, a focused neuro exam, and basic labs (CBC, BMP, UA, ammonia if suspected, head CT for trauma or focal findings).
In elderly patients, UTI is so common a cause that a urine dip before deeper workup is routine. In young patients, think tox screen and acute psychosis earlier. AANP loves pairing a vignette (sudden confusion + fever) with a differential that requires you to broaden first, then narrow.
Related Mnemonics
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