A 70-year-old woman presents with progressive memory loss, visuospatial difficulties, and then parkinsonism. She dies 2 years later. Autopsy shows neuronal loss in the substantia nigra, locus coeruleus, and cerebral cortex. Immunohistochemistry with anti-alpha-synuclein antibody shows Lewy bodies in cortical neurons and dorsal vagal nucleus. Which clinical-pathological classification is this?

• A Parkinson's disease — Braak stage VI (cortical Lewy body involvement) with dementia (PDD) developing >1 year after parkinsonism
• B Multiple system atrophy (MSA-P type) — glial cytoplasmic inclusions (GCIs) in oligodendrocytes, not Lewy bodies in neurons
• C Dementia with Lewy bodies (DLB) — dementia precedes or occurs within 1 year of parkinsonism; core features include fluctuating cognition, visual hallucinations, and REM sleep behavior disorder ✓
• D Progressive supranuclear palsy (PSP) — tau-positive neurofibrillary tangles in subthalamic nucleus and brainstem, not alpha-synuclein

Explanation

Dementia with Lewy bodies (DLB) is defined clinically by: dementia preceding parkinsonism or developing concurrently/within 1 year. Core clinical features include fluctuating cognition, recurrent visual hallucinations, REM sleep behavior disorder (RBD), and parkinsonism. Pathologically, alpha-synuclein Lewy bodies are found in brainstem and ALSO in limbic and neocortical regions (Braak stages 5–6). The distinction from PDD is clinical: parkinsonism >1 year before dementia = PDD. MSA has GCIs in oligodendrocytes (glial alpha-synuclein); PSP has tau-positive tangles with 4-repeat tauopathy. DLB is the second most common degenerative dementia after Alzheimer's.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.