Dementia with Lewy Bodies — RACP Adult Medicine MCQ

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EasyNeurologyDementia with Lewy BodiesRACP Adult Medicine

A 55-year-old woman with progressive cognitive decline over 12 months has prominent visual hallucinations, fluctuating attention, and REM sleep behaviour disorder. Her MMSE is 22/30. Examination shows bilateral rigidity and bradykinesia. What is the most likely diagnosis?

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Correct answer: C — Dementia with Lewy bodies

The core clinical features of DLB are: fluctuating cognition with pronounced variation in attention and alertness, recurrent visual hallucinations (typically well-formed and detailed), REM sleep behaviour disorder, and spontaneous parkinsonism. Two or more core features establish a probable DLB diagnosis. DLB is distinguished from PD dementia by the '1-year rule' – if dementia precedes or occurs within 1 year of parkinsonism, the diagnosis is DLB. Cholinesterase inhibitors (rivastigmine) are first-line treatment.

Reference: eTG – 2025 – Neurology; DLB Consortium – 2017 – Diagnostic Criteria