Difference in Disease Burden and Activity in Pediatric Patients on Brain Magnetic Resonance Imaging at Time of Multiple Sclerosis Onset vs Adults

Objective: To compare initial brain magnetic resonance imaging (MRI) characteristics of children and adults at multiple sclerosis (MS) onset. Design: Retrospective analysis of features of first brain MRI available at MS onset in patients with pediatric-onset and adult-onset MS. Setting: A pediatric and an adult MS center. Patients: Patients with pediatric-onset <18 years) and adult-onset (>= 18 years) MS. Main Outcome Measures: We evaluated initial and second (when available) brain MRI scans obtained at the time of first MS symptoms for lesions that were T2-bright, ovoid and well defined, large (>= 1cm), or enhancing. Results: We identified 41 patients with pediatric-onset MS and 35 patients with adult-onset MS. Children had a higher number of total T2- (median, 21 vs 6; P <.001) and large T2-bright areas (median, 4 vs 0; P <.001) than adults. Children more frequently had T2-bright foci in the posterior fossa (68.3% vs 31.4%; P=.001) and enhancing lesions (68.4% vs 21.2%; P <.001) than adults. On the second brain MRI, children had more new T2-bright (median, 2.5 vs 0; P<.001) and gadolinium enhancing foci (P<.001) than adults. Except for corpus callosum involvement, race/ethnicity was not strongly associated with disease burden or lesion location on the first scan, although other associations cannot be excluded because of the width of the confidence intervals. Conclusion: While it is unknown whether the higher disease burden, posterior fossa involvement, and rate of new lesions in pediatric-onset MS are explained by age alone, these characteristics have been associated with worse disability progression in adults.