skip to main content

Dementia with Lewy Bodies — RACP Adult Medicine MCQ

Instant feedback + full explanation. One question, done properly.

ModerateNeurologyDementia with Lewy BodiesRACP Adult Medicine

A 68-year-old man presents with cognitive decline, detailed visual hallucinations (seeing children and animals), fluctuating cognition (good and bad days), REM sleep behaviour disorder, and parkinsonism (bradykinesia, rigidity). He has autonomic dysfunction (orthostatic hypotension, constipation). Cognition preceded parkinsonism by 18 months. What is the most likely dementia subtype?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Dementia with Lewy bodies

Visual hallucinations, fluctuating cognition, RBD, parkinsonism (1-year rule: dementia before or within 1 year of parkinsonism = DLB; parkinsonism >1 year before dementia = PDD), and autonomic dysfunction fulfils revised McKeith criteria for dementia with Lewy bodies. DLB patients are exquisitely sensitive to antipsychotics (can cause severe neuroleptic malignancy/rigidity — AVOID). Cholinesterase inhibitors are first-line for cognitive and neuropsychiatric symptoms.

Reference: McKeith – 2023 – DLB Criteria; eTG Neurology 2024