A 32-year-old woman presents with an episode of unilateral optic neuritis. MRI brain shows 3 periventricular T2 hyperintense lesions, one of which is Dawson's finger orientation. CSF shows oligoclonal bands in 8 fractions. She has had no prior neurological episodes. What is the diagnosis at this stage?
- A Relapsing-remitting multiple sclerosis (RRMS) ✓
- B Clinically isolated syndrome (CIS)
- C Radiologically isolated syndrome (RIS)
- D Neuromyelitis optica spectrum disorder (NMOSD)
Correct answer: A. Relapsing-remitting multiple sclerosis (RRMS)
Explanation
Per the 2017 McDonald Criteria, a clinically isolated syndrome (single attack) can be diagnosed as MS without a second attack if MRI shows dissemination in space AND CSF shows oligoclonal bands, which serve as a proxy for dissemination in time. This patient has a single attack (optic neuritis), MRI demonstrating dissemination in space (≥2 typical periventricular lesions with Dawson's fingers), and CSF OCBs — all meeting the 2017 revised criteria for RRMS diagnosis. CIS would apply if MRI criteria for DIT were not met and no CSF OCBs were present.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.