Neurodegenerative Diseases USMLE Step 1 Practice Question
A 4-year-old boy presents with delayed motor milestones, frequent falls, and progressive difficulty rising from the floor. Vital signs: BP 95/60, HR 98, RR 20, Temp 37°C, SpO2 98%. Physical examination reveals bilateral calf pseudohypertrophy and a positive Gowers sign. Serum creatine kinase is markedly elevated at 8,500 IU/L. Cognitive examination is normal. Which of the following is the most likely diagnosis?
Answer choices
- ADuchenne muscular dystrophyCorrect answer
- BAmyotrophic lateral sclerosis
- CBecker muscular dystrophy
- DMyotonic dystrophy
- ESpinal muscular atrophy
- FLimb-girdle muscular dystrophy
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