Predicting short-term conversion from CIS to MS: relevance of lesion distribution

Clinically isolated syndrome (CIS) describes a first symptomatic neurologic episode that is consistent with multiple sclerosis (MS), lasts at least 24 hours, occurs in the absence of fever or infection, and presents without encephalopathy.(1) Its cause is inflammation or demyelination in one (i.e., monofocal episode) or multiple areas (i.e., multifocal episode) of the CNS. Symptoms are those commonly found in MS and include, for example, optic neuritis, sensory or motor signs, partial myelitis, and bladder or bowel dysfunction.(1).