Neurodegenerative Diseases USMLE Step 1 Practice Question
A 55-year-old woman with hypertension presents with sudden severe headache and diplopia. Vital signs show BP 168/98 mmHg, HR 88/min, RR 16/min, temp 37.2°C. Examination reveals right ptosis, right eye deviated down and out, and a dilated poorly reactive right pupil. MRI brain demonstrates a posterior communicating artery aneurysm. There is no neck stiffness or photophobia. She denies recent trauma or anticoagulant use. Which of the following is the most likely cause?
Answer choices
- ALesion of the medial longitudinal fasciculus
- BPICA infarction
- CBasilar artery thrombosis
- DPosterior communicating artery aneurysm compressing CN IIICorrect answer
- EMicrovascular ischemic injury to CN VI
- FCavernous sinus thrombosis secondary to ethmoid sinusitis
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