A 72-year-old woman post-hip replacement surgery develops acute onset fluctuating confusion, inattention, and visual hallucinations on day 2. Her MMSE score fluctuates between 16 and 24 within hours. The single most important reversible cause to exclude FIRST is:

• A New-onset Alzheimer's dementia triggered by surgical stress
• B Hypertensive encephalopathy from perioperative blood pressure changes
• C Subcortical vascular dementia developing acutely
• D Opioid-induced delirium from postoperative analgesia, compounded by anticholinergic medications ✓

Explanation

Post-operative delirium (POD) is most commonly precipitated by medications — opioids (morphine metabolites accumulate in renal impairment), anticholinergics (promethazine, some antihistamines, bladder medications), and benzodiazepines. These are the most immediately reversible causes and should be reviewed and rationalised first. A stepwise delirium workup (infection, metabolic, medication, CNS) should follow. Alzheimer's disease does not present acutely; vascular dementia is typically stepwise rather than acutely fluctuating.

Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.