DLB — MRCPsych Paper B MCQ

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ModerateOld Age PsychiatryDLBMRCPsych Paper B

A 68-year-old man has an 18-month history of progressive cognitive decline that now prevents him from managing his finances independently. His attention and alertness fluctuate markedly, and he experiences recurrent, detailed visual hallucinations of children playing in his garden. Rigidity and bradykinesia developed during the same period. His wife also reports that he punches and kicks while apparently acting out his dreams. Which is the most likely diagnosis?

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Correct answer: A — Dementia with Lewy bodies

This is dementia with Lewy bodies. He has established dementia plus all four core clinical features: marked cognitive fluctuations, recurrent well-formed visual hallucinations, REM sleep behaviour disorder and spontaneous parkinsonism. The cognitive and motor syndromes developed during the same period, supporting DLB rather than Parkinson's disease dementia. Alzheimer's disease usually presents with prominent progressive episodic-memory impairment; hallucinations and parkinsonism are generally later features. Vascular dementia is suggested by a temporal relationship to cerebrovascular events, focal neurological signs or a stepwise course. Frontotemporal dementia more often causes early behavioural, executive or language change. Creutzfeldt-Jakob disease typically progresses rapidly over weeks to months and is associated with features such as myoclonus, ataxia and pyramidal or extrapyramidal signs.

Reference: London Dementia Clinical Network, Neuroimaging for dementia: guidance from the London Dementia Clinical Network, section 'DAT scan in dementia with Lewy bodies', 2018. https://www.rcpsych.ac.uk/docs/default-source/members/faculties/old-age/neuroimaging-for-dementia---guidance-from-london-dementia-clinical-network.pdf?sfvrsn=1d1bcbe5_4