What is Multiple Sclerosis (MS)? What is POMS?
MS: Neuroinflammatory or demyelinating disorder of the central nervous system (CNS) including brain and/or spinal cord.
POMS: Diagnosis of MS before 18 years of age, with diagnosis before 10-12 years of age being rare. About 3-5% of MS cases worldwide are pediatric onset.
What are risk factors to develop POMS?
There are several known risk factors associated with POMS, many of which overlap with adult-onset multiple sclerosis (AOMS).
Environmental factors: These include cigarette smoke exposure, prior EBV infection, lower vitamin D levels, and obesity. Recent studies have even shown that early sun exposure prenatally and in the first year of life is associated with lower relapse risk!
Genetics: There is a genetic risk as well with the most common gene identified as: HLA-DRB1*1501. Children or individuals with first degree relatives with MS, have a 2-4% increased risk of developing MS.
Puberty: The risk of developing MS in males and females is equivalent pre-puberty. However, at onset or post-puberty, females have a 2-3 times higher risk of developing MS compared to males.
How do POMS patients present?
POMS patients can have a highly variable clinical presentation, with overlap with AOMS. Common presenting symptoms include vision changes (loss of vision or diplopia), paresthesias, weakness, ataxia, and/or urinary symptoms. The initial attack typically occurs as a monofocal clinical event, meaning the symptoms localize to a single area of the CNS. Younger children (<10 years of age) are more likely to have encephalopathy, brainstem involvement, and polyfocal deficits.
What are treatment options for POMS?
There is currently only one disease modifying treatment (DMT) approved for pediatric patients – Fingolimod (Gilenya). Several trials for other DMTs are ongoing at this time.
How does the disease course differ between POMS and AOMS?
Most POMS patients (>98%) have a relapsing-remitting course. POMS patients have more frequent and severe relapses in the first few years post-diagnosis compared to AOMS but tend to recover more quickly and completely compared to adults. Though pediatric patients had slower disability progression compared to adult patients, they reached significant disability milestones at a younger age. Brainstem involvement, poor recovery from a single attack, and higher frequency of attacks lend to a greater likelihood of future disability.
About one-third of these patients have evidence of significant cognitive impairment early on with progression within the first two years and thus neurocognitive testing is imperative, ideally within the first year of diagnosis.
Waldman, Amy et al. “Pediatric multiple sclerosis: Clinical features and outcome.” Neurology vol. 87,9 Suppl 2 (2016): S74-81. doi:10.1212/WNL.0000000000003028