Neuromuscular Disorders USMLE Step 1 Practice Question
A 7-year-old girl develops progressive ascending weakness over 2 days while camping in the summer. Reflexes are decreased. She is afebrile, and CSF protein is normal. Careful skin examination reveals an engorged tick at the scalp line. Removal of the tick leads to improvement. Which of the following best explains this disorder?
Answer choices
- AAnterior horn cell degeneration from viral infection
- BPostinfectious autoimmune demyelination
- CPresynaptic blockade of acetylcholine release by tick toxinCorrect answer
- DAutoimmune destruction of acetylcholine receptors
- EMutation in PMP22
- FCompetitive blockade of acetylcholine at the neuromuscular junction
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