Neurodegenerative Diseases USMLE Step 1 Practice Question
A 58-year-old man presents with 6-month progressive hand weakness and muscle atrophy. Examination reveals visible fasciculations in bilateral upper extremities, brisk patellar reflexes bilaterally, and normal sensation throughout. Vital signs: BP 128/82, HR 82, RR 16, temp 37°C, SpO2 98%. Recent EMG shows denervation potentials and reduced motor unit recruitment. Bowel and bladder function remain intact. He takes no medications. Which diagnosis best explains these findings?
Answer choices
- AMyasthenia gravis
- BAmyotrophic lateral sclerosisCorrect answer
- CGuillain-Barre syndrome
- DSubacute combined degeneration
- EMultiple sclerosis
- FMyasthenia gravis with concurrent cervical myelopathy
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