Pediatric-onset multiple sclerosis in Brazilian patients: Clinical features, treatment response and comparison to pediatric neuromyelitis optica spectrum disorders.

BACKGROUND: Multiple Sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are acquired demyelinating syndromes of the central nervous system more frequently in young adults and their beginning before 18 years of age is rare. They are autoimmune diseases with distinct pathophysiology, clinical presentation, treatment and prognoses. During childhood these conditions often present similar clinical features and differential diagnosis among pNMOSD, pMS and acute disseminated encephalomyelitis (ADEM) is still difficult at disease onset. The aim of this article is to describe the epidemiologic and clinical features, to evaluate the response to treatment and to compare the mains characteristics between the patients with MS and NMOSD who had the first event prior to 18 years of age followed at the Universidade Federal de São Paulo (UNIFESP).

METHODS: Retrospective analysis of patients with MS and NMOSD who started the disease before 18 years of age followed for at UNIFESP. All patients fulfilled the McDonald 2010 criteria for MS and the IPND 2015 criteria or 2006 diagnostic criteria for NMOSD. For treatment analysis, we select patients with a follow-up of more than 6 months.

RESULTS: Sixty-eight patients fulfilled the inclusion criteria for MS and were selected for analysis. Mean age of onset was 15 years, 73.5% were female and the mean follow-up was 6.7 years. Mean annualized relapse rate (aRR) observed was 0,82 relapse/year and mean progression index (PI) was 0.31 EDSS points/year. The multivariate analysis showed a significant association between the EDSS on first appointment and total number of relapses with neurological disabilities in long term in patients with MS. The treatment with interferon-beta (IFN-β) and glatiramer acetate (GA) was safe and patients treated with high dose IFN-β and GA had a statistically significant reduction in disability progression. Eleven patients fulfilled the inclusion criteria for NMOSD: mean age of onset was 14 years, 72.7% were female and the mean follow-up was 6.3 years. Mean aRR observed was 1.5 relapse/year and mean PI was 2.2 EDSS points/year. The treatment with azathioprine was safe and significant halts disability progression. Patients with NMOSD reached EDSS 6 prior than those with MS.

CONCLUSIONS: Pediatric demyelinating diseases in Brazil are similar to the diseases described abroad. In patients with pMS, the EDSS score at the first appointment and the total number of relapses were associated with poor prognosis. NMOSD is more severe than MS in pediatric patients. Treatment with DMD and azathioprine was well tolerated and effective in reducing relapse rate and disability.