Neurodegenerative Diseases USMLE Step 1 Practice Question
A 60-year-old male smoker with a 40 pack-year history presents with progressive proximal leg weakness and dry mouth over 3 weeks. Vital signs show BP 138/82 mmHg, HR 92/min, RR 16/min, temp 37.0°C, SpO₂ 94% on room air. Deep tendon reflexes are diminished but transiently improve after repeated muscle contraction. Serum calcium is normal. Chest CT reveals a 3-cm central lung mass. Cranial nerves are intact. Which diagnosis best explains these findings?
Answer choices
- ALambert-Eaton myasthenic syndromeCorrect answer
- BBotulism
- CPolymyositis
- DGuillain-Barre syndrome
- EMyasthenia gravis
- FParaneoplastic cerebellar degeneration from anti-Yo
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