What an adult multiple sclerosis registry can tell us about pediatric onset multiple sclerosis?

Multiple Sclerosis (MS) is an immune-mediated, chronic disease of the central nervous system that affects mainly adults. However, it is increasingly recognized that MS may start in childhood resulting in a relentlessly progressive disability and cognitive impairment. Registries across the globe are reporting inconstant data about their Pediatric-Onset Multiple Sclerosis (POMS) patients. Moreover, newer lines of treatments are emerging and showing efficacy in controlling the MS disease regardless of the onset. Therefore, there is a requirement for more research into the clinical profile of POMS in different populations and ethnicities.

This study was a cross-sectional study that included MS patients who visited the MS unit at Alexandria University from January 2019 to January 2021. We analyzed their epidemiological, clinical, radiological data, and cerebrospinal fluid (CSF) results from their updated records as well as follow-up interviews.

Annual Relapse Rate (ARR) was marginally less in POMS than AOMS (0.72 ± 0.57 vs 1.04 ± 0.78 relapse/year, P =.008). POMS patients had a bigger gap to their first relapse (40.0 ± 47.35 vs 22.71 ± 34.33 months, p= .066). The difference in relapse rate between the two groups was abolished after the exclusion of patients who had a gap of more than 5 years to their first relapse. AOMS patients were significantly more likely to start with a second-line disease-modifying treatment (DMT) than POMS patients (11.5% vs 31%, p= .04), whereas POMS patients were more likely to be escalated to the second line (34.6% vs 19.3%, p= .07). ARR had a positive and significant correlation with expanded disability status scale (EDSS) progression per year (r_s(24)= .57 p=.003). A Mann-Whitney test indicated that POMS patients who had infratentorial involvement in the initial MRI brain had higher EDSS (3.08 ± 1.99) than POMS who did not (1.07 ± 0.79) U=24 P =.013. IgG index had a significant and positive correlation with annual EDSS progression rate r_s (8) = 0.8 p=.001.

Early disease onset does not mean a higher relapse rate when including the full spectrum of POMS and longer follow-up duration. POMS patients relapsed more on the first-line DMT and escalation should be considered early. Infratentorial involvement in the initial magnetic resonance imaging (MRI) brain and high IgG index are potential predictors for aggressive disease course in POMS.