Neuromuscular Disorders USMLE Step 1 Practice Question
A 15-year-old boy presents with progressive difficulty running and recurrent ankle sprains over the past year. Vital signs are normal (BP 118/76, HR 82, RR 16, Temp 98.6°F, SpO2 98%). Physical examination reveals pes cavus bilaterally, distal leg muscle wasting, and diminished vibration sensation in the feet. Strength testing shows 4/5 ankle dorsiflexion. Nerve conduction studies demonstrate slowed conduction velocities in lower extremities. There is no upper extremity involvement. Which diagnosis best explains these findings?
Answer choices
- ACharcot-Marie-Tooth diseaseCorrect answer
- BTabes dorsalis
- CPolymyositis
- DGuillain-Barré syndrome
- EFriedreich ataxia
- FSpinal muscular atrophy
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