Increased Relapse Frequency in Females with Pediatric Onset Multiple Sclerosis

Background:  Pediatric onset multiple sclerosis (POMS) has been increasingly recognized over the last fifteen years. The Center for Pediatric Onset Demyelinating Disease (CPODD) at the University of Alabama at Birmingham was established in 2006 to provide long-term follow-up for children and adolescents with POMS and related demyelinating disorders. 

 Objectives: Characterize POMS patients evaluated at CPODD from January 1, 2006 to December 31, 2013.

 Methods:  CPODD patients (n=359) were categorized using the 2012 International Pediatric MS Study Group diagnostic criteria. POMS patients were analyzed with respect to age of onset, race/ethnicity, sex, initial symptoms, and number of exacerbations within two years of initial presentation and disease modifying therapy (DMT).

Results:   Nearly one-third of the CPODD cohort developed POMS (n=114, 31%). POMS patients are predominantly female (65%) and disproportionately African-American (43%); <2% were Hispanic or Asian, remainder were Caucasian.   Mean age of symptom onset was 13.1 ± 4 with 22% ≤ 10 years old, 41% from 11-14 years old and 37% from 15-18 years.  The majority of POMS patients presented with clinically isolated syndrome (89%, n=101); symptoms were characterized as pyramidal (n=45; 39%), brainstem/cerebellar (n=34; 30%) or ON (n=18; 16%).   A minority presented with ADEM (n=7; 6%), radiologically isolated syndrome (n=5; 4%), paroxysmal dysarthria (n=2; 2%), behavioral symptoms (n=1; 1%); or seizures (n=2; 2 %).   Over two-thirds of POMS patients had follow-up ≥2 years (N=78; 68%). All POMS patients were started on DMT, most within 12 months of symptom onset.  Of those patients with follow-up >2 years, nearly half had 0 exacerbations (n=37; 47%), nearly one-third had 1 exacerbation (n=23; 30%), 13% had 2 exacerbations (n=10) and 10% had between 3-6 exacerbations. Female had significantly more relapses than males (chi-square p <0.001), but there was no correlation between the number of relapses and age of onset or race.

Conclusions: POMS in this southern U.S. cohort was predominantly female and > age 11 at symptom onset. Similar to adults, the typical presentation is CIS, although ON was relatively infrequent.  Over 75% experience ≤1 relapse within the first two years after symptom onset, however females had a higher number of relapses than males.