There are four disease courses that have been identified in multiple sclerosis:
clinically isolated syndrome (CIS); relapsing-remitting MS (RRMS); primary progressive MS (PPMS); and secondary progressive MS (SPMS).
1. Clinically Isolated Syndrome: With neurologic symptoms caused by inflammation and demyelination in the central nervous system, this first episode — which must last at least 24 hours, according to definition — is typical of multiple sclerosis but does not yet meet the criteria for a diagnosis of the disease. People who have a clinically isolated syndrome will not necessarily go on to develop multiple sclerosis. An MRI will better determine the likelihood that someone who has a CIS will develop MS. If lesions on a brain MRI are seen with CIS, there is a higher chance the patient will develop MS.