skip to main content

Dementia with Lewy bodies — MCCQE Part 1 MCQ

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

HardMemory LossDementia with Lewy bodiesMCCQE Part 1

A 72-year-old was diagnosed with idiopathic Parkinson disease 4 years ago after asymmetric bradykinesia and rest tremor responded to levodopa. Over the past year he has developed progressive executive and visuospatial impairment that interferes with medications and finances. Examination and laboratory testing reveal no delirium or reversible cause. What is the most likely diagnosis?

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

Reveal the answer and explanation

Correct answer: D — Parkinson disease dementia

Clinically significant dementia began several years after established Parkinson disease, fitting Parkinson disease dementia under the useful one-year timing rule. Dementia preceding parkinsonism or beginning within one year would favour dementia with Lewy bodies. The gradual course and exclusion of acute precipitants argue against delirium; the temporal and motor pattern is less consistent with Alzheimer or frontotemporal dementia. Functional decline, rather than an isolated low cognitive-test score, establishes the clinical significance of the cognitive syndrome.

Reference: DLB Consortium diagnostic consensus: https://pmc.ncbi.nlm.nih.gov/articles/PMC5496518/