Demyelinating Diseases USMLE Step 1 Practice Question
A 37-year-old woman undergoes MRI for suspected MS and is found to have multiple brain T2 lesions, but only 1 lesion shows gadolinium enhancement. Spine MRI is normal. She reports mild cognitive difficulties but no recent relapses. Which of the following supports a diagnosis of MS over other demyelinating conditions?
Answer choices
- ACognitive symptoms are pathognomonic for MS
- BThe presence of gadolinium enhancement indicates acute demyelination specific to MS
- CEvidence of dissemination in space with both enhancing and non-enhancing lesions of different agesCorrect answer
- DNormal spine MRI confirms that this is MS rather than myelitis-associated disease
- EAbsence of spinal cord involvement excludes other demyelinating diseases
- FPresence of T2 lesions in the brain without corresponding gadolinium enhancement indicates chronic MS with inactive disease
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.