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Delirium — USMLE Step 3 MCQ

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HardPsychiatry (outpatient management)DeliriumUSMLE Step 3

An 84-year-old becomes acutely confused and inattentive after starting oxybutynin. Symptoms fluctuate and are worse at night. What is the most likely diagnosis?

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Correct answer: D — Acute delirium with fluctuating attention and altered awareness

Acute onset, fluctuation, and inattention indicate delirium, with anticholinergic medication a likely precipitant. Management starts with identifying and reversing causes rather than labeling a chronic dementia.

Reference: American Geriatrics Society 2023 Beers Criteria: https://pmc.ncbi.nlm.nih.gov/articles/PMC12478568/