A 52-year-old man with chronic alcohol use disorder presents with gait ataxia, nystagmus, and dysarthria. Imaging reveals selective degeneration of the cerebellar vermis. Which is the most common site of cerebellar pathology in chronic alcoholism?

Explanation

## Cerebellar Degeneration in Chronic Alcoholism **Key Point:** The cerebellar vermis is the most common and characteristic site of damage in alcoholic cerebellar degeneration, leading to the classic triad of gait ataxia, nystagmus, and dysarthria. ### Pathophysiology Alcohol causes selective degeneration of Purkinje cells in the anterior and superior cerebellar vermis, which is responsible for: - Trunk and lower limb coordination (gait control) - Balance and posture - Midline cerebellar functions ### Clinical Presentation | Feature | Vermis Lesion | Hemispheric Lesion | |---------|---------------|--------------------| | Gait ataxia | **Present (early)** | Absent or mild | | Limb dysmetria | Absent | **Present** | | Nystagmus | **Present** | Absent | | Dysarthria | **Present** | Absent | | Hypotonia | Mild | **Marked** | **High-Yield:** Alcoholic cerebellar degeneration preferentially affects the vermis because: 1. Thiamine (vitamin B1) deficiency impairs pyruvate dehydrogenase complex 2. Purkinje cells in the vermis are metabolically vulnerable 3. Direct toxic effect of acetaldehyde on granule and Purkinje cells **Clinical Pearl:** The vermis-predominant pattern in alcohol-related cerebellar disease is so characteristic that it is sometimes called "alcoholic cerebellar syndrome" with the vermis as the signature lesion. **Mnemonic:** **VERM** = **V**ermis is the **E**arliest site in **R**ecurrent **M**ethanol/alcohol toxicity.