Demyelinating Diseases USMLE Step 1 Practice Question
A 25-year-old woman presents with 2 days of painful vision loss in her right eye with desaturated color perception, especially red objects. Vital signs: BP 118/76, HR 88, RR 16, Temp 37.2°C, SpO2 98%. Examination reveals right afferent pupillary defect and normal extraocular movements. MRI brain shows T2 hyperintense lesion in the right optic nerve. She denies recent fever or systemic symptoms. Which of the following is the most likely diagnosis?
Answer choices
- AProgressive multifocal leukoencephalopathy
- BPsychogenic nonepileptic seizure
- CMyasthenia gravis
- DOptic neuritisCorrect answer
- EInternuclear ophthalmoplegia from medial longitudinal fasciculus lesion
- FLeber hereditary optic neuropathy from mitochondrial DNA mutation
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