## Pathological Hallmark of Lewy Body Dementia **Key Point:** Alpha-synuclein is the primary pathological protein in Lewy body dementia (LBD), forming intracytoplasmic inclusions known as Lewy bodies and Lewy neurites. ### Lewy Body Composition Lewy bodies are abnormal protein aggregates composed of: 1. Alpha-synuclein (core component) 2. Ubiquitin 3. Neurofilament proteins ### Distribution in LBD - **Cortical Lewy bodies** → cognitive decline, hallucinations - **Brainstem Lewy bodies** → Parkinsonian features (rigidity, bradykinesia) - **Limbic system involvement** → mood and behavioral changes ### Comparison with Other Dementias | Dementia Type | Primary Protein | Secondary Pathology | |---|---|---| | Lewy Body | Alpha-synuclein | Amyloid-beta, tau (often present) | | Alzheimer's | Amyloid-beta, tau | Alpha-synuclein (sometimes) | | Frontotemporal | Tau or TDP-43 | Variable | | Parkinson's Disease | Alpha-synuclein | Brainstem-predominant | **High-Yield:** LBD is the second most common neurodegenerative dementia after Alzheimer's disease. The presence of alpha-synuclein pathology distinguishes LBD from pure Alzheimer's pathology. **Clinical Pearl:** Patients with LBD often have prominent visual hallucinations (seeing people, animals) early in the disease course, which is less typical of Alzheimer's dementia.
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.