Pediatric Multiple Sclerosis
Clinical Features, Progression, and Outcomes
In pediatric MS, the onset occurs before age 16; in children, the disease progresses slower than it does in adults although permanent disability occurs at a younger age
Pediatric multiple sclerosis (MS) is defined as multiple sclerosis with an onset before the age of 16 years. To determine the clinical features, occurrence of outcomes, and conversion to secondary progression and irreversible disability in children, Christel Renoux and her colleagues in France conducted a study, which was published in The New England Journal of Medicine (June 21, 2007, vol 356 (25): 2603-2613).
Study Methods
Researchers used data collected between 1976 and 2003 from 13 adult neurology departments affiliated with the European Database for Multiple Sclerosis (EDMUS) network. From this study, Renoux identified 394 patients who had an onset of MS at 16 years of age or younger. These patients were compared to a comparison group of 1775 MS patients with adult onset disease.
Who is Affected?
Pediatric multiple sclerosis is reported to occur in 0.4 to 10.5 percent of all MS cases. Children with MS are more often female when compared to adults (2.8:1.8 female to male ratio in children). The mean age of onset for pediatric patients was 13.7 years. In 7.6 percent of patients, onset occurred before age 10, in 18.0 percent of patients, disease onset was at 12 years or younger, and in 40.4 percent of patients disease onset was at 14 years or younger.
Differences in Childhood MS
Using the Kurtzke Disability Status Scale and prognostic factors such as sex, age at disease onset, type of initial disease course and symptoms, the time interval between the first two neurologic episodes, the number of relapses during the first two years from disease onset, and the decade of onset of MS, the researchers found that children with MS are more likely to have an exacerbating-remitting initial disease course (98 percent vs 84 percent in adults). In the study, only 2.3 percent of patients had a progressive initial course and these patients were all older than 13 years at the time of disease onset.
The researchers also found that children take about 10 years longer to progress to irreversible disability than adults, although children will do so at a younger age. Also, 7.4 percent of pediatric patients showed encephalitic signs, including headache, vomiting, seizures, or disorders of consciousness and were more likely to develop isolated optic neuritis and less likely to develop isolated dysfunction of long tracts.
Disease Course
The estimated time between the first two neurologic episodes in children in the study was 2.0 years. The estimated median time from the onset of MS to conversion to secondary progression was 28.1 years, and the estimated median age at conversion was 41.4 years.
The estimated median times from the onset of MS to the assignment of irreversible disability with a DSS score of 4 was 20 years; DSS score of 6, 28.9 years; DSS score of 7, 37.0 years. A progressive course at disease onset and having more relapses during the first two years from disease onset increased the rate of disability by 31 to 41 percent. Age at the onset of MS, however, was not a prognostic factor for disability.
Treatment
About half of the pediatric patients in the study were treated with immunoactive drugs such as azathioprine mainly during the relapsing-remitting phase. These medications haven’t been shown to influence long-term disability. Treatment was also started later in the disease course and couldn’t modify the early disease course. A similar study using promising treatments such as low dose naltrexone and nutritional support, for instance increased vitamin D, would be worthwhile.
