An 80-year-old man with well-controlled hypertension develops fluctuating consciousness, visual hallucinations, and severe attention deficits over 2 days following hip replacement surgery. He was oriented before surgery. Vitals show mild tachycardia. His son reports his father was 'perfectly fine' before surgery. What is the MOST likely diagnosis?
- A Dementia with Lewy bodies
- B Delirium, postoperative ✓
- C New-onset Alzheimer's disease
- D Vascular dementia
Explanation
Delirium is characterized by acute onset (hours to days), fluctuating consciousness/attention, and cognitive changes not explained by a neurocognitive disorder. Postoperative delirium is common in elderly patients due to anesthesia, pain medications, sleep deprivation, electrolyte disturbances, and immobility. The acute onset (2 days), fluctuating course, normal baseline, and temporal relation to surgery strongly favor delirium. Dementia with Lewy bodies also causes fluctuating cognition and visual hallucinations but has an insidious onset over months to years. Alzheimer's is insidious and progressive, not acute.
Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.
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Written and medically reviewed by the StethoPrep medical team.