Neuromuscular Disorders USMLE Step 1 Practice Question
A 63-year-old man presents with a 3-month history of difficulty rising from a chair and dry mouth. Vital signs: BP 142/88 mmHg, HR 88/min, RR 16/min, temp 37°C, SpO2 98% on room air. Strength improves with repeated muscle activation. Deep tendon reflexes are decreased throughout. Serum creatine kinase is mildly elevated at 450 U/L. Sensory examination is intact. He denies recent medications. Which of the following is the most likely diagnosis?
Answer choices
- AMultiple sclerosis
- BBotulism
- CLambert-Eaton myasthenic syndromeCorrect answer
- DPolymyositis
- EMyasthenia gravis
- FNecrotizing autoimmune myopathy (anti-HMGCR antibody-associated)
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