Unfavorable outcome of pediatric onset multiple sclerosis: Follow-up in the pediatric and adult neurology departments of one referral center, in Turkey

•The clinical phenotype of pediatric-MS patient is heterogenous.•There is a group of patient who develop secondary progressive course around ten years.•Seizure and cognitive decline, possible result of cortical involvement, may predict severe course.

Background:The prevalence of MS starting under 18 years of age ranges between 2-10% of the total MS population.Objective:We aimed to examine the clinical and long term follow-up data of pediatric-onset cases in our institutional MS database.Method:We evaluated the clinical data from the MS database of the Departments of Neurology and Pediatric Neurology of Hacettepe University Hospital.Results:The clinical features of 74 patients who had experienced the first attack before age 18 years comprised 3.9% of our MS population. Median age at onset was 15 (3, 5-17, IQR=3.63) years, and female: male ratio was 2.4. The most frequent symptom at onset was brainstem/cerebellar dysfunction (32.4%). Seventy two patients (97.3%) initially had relapsing remitting course and in the follow-up, 17 (23%) of them developed secondary progressive (SP) course. The median interval to develop SPMS course was 10 (5-21, IQR=8) years. At the last visit, median disease duration was 6.67 (0.83-25, IQR=9.06) years, 41 (55.4%) of them had EDSS of ≥4.Conclusion:These findings illustrate the profile of our pediatric MS patients: almost all are relapsing-remitting initially; about one fourth become secondarily progressive in 10 years, and about half acquire disability EDSS ≥4 in mean 8 years.