Neurodegenerative Diseases USMLE Step 1 Practice Question
A 31-year-old woman presents with acute diplopia. Vital signs: BP 118/76, HR 88, RR 16, Temp 37.0°C, SpO2 98%. On examination, left gaze reveals failure of right eye adduction with left eye abduction nystagmus; convergence remains intact. MRI brain shows T2 hyperintensity in the medial longitudinal fasciculus. She denies recent fever or headache. Which structure is most likely affected?
Answer choices
- AEdinger-Westphal nucleus
- BAbducens nerve
- COculomotor nerve nucleus
- DMedial longitudinal fasciculusCorrect answer
- EOptic chiasm
- FLateral rectus nucleus
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