Clinical Profile, Prognostic Indicators, and Therapeutic Outcomes of Pediatric Opsoclonus-Myoclonus-Ataxia Syndrome: A Single-Center Experience from South India.

Abstract

Background:Opsoclonus myoclonus syndrome (OMS) is a neuroinflammatory disorder. Indian literature on its clinical profile and outcome is sparse.Objectives:The objective of this study is to describe the clinical profile and analyze outcomes and prognostic predictors in a cohort of children with OMS.Materials and Methods:This was a retrospective study of children with OMS between 2007 and 2017.Results:Twenty-two children were included in the study. The mean age at onset of symptom was 20.9 months (standard deviation [SD]: 7.5). The mean duration of delay in diagnosis was 8.4 months (SD 1.26) with acute cerebellitis being the most common misdiagnosis. Eleven children (50%) were diagnosed with tumor during evaluation and follow-up and 11 children (50%) belonged to idiopathic/postinfectious group. Magnetic resonance imaging brain was normal in all children except for one revealing cerebellar atrophy on follow-up. One child in the paraneoplastic group (neuroblastoma) had a positive PNMA2/Ta onconeural antibody. Children in the tumor group had an earlier age of onset (mean 15.5 vs. 26.3 months), shorter time to onset of opsoclonus from initial symptom (2.54 vs. 7.27 weeks), and higher severity score at presentation (13.7 vs. 11.3) compared to the nontumor group. Children in the nontumor group attained their first remission with treatment earlier (10.9 weeks, SD: 4.5) than the children with tumor (18.72 weeks, SD: 5.8). There was no significant difference in the outcome between the groups. Children with multiple relapses (>3) and late surgical intervention for tumor (>6 months after symptom onset) had a poor outcome.Discussion:A high index of suspicion coupled with early diagnosis and periodic tumor surveillance (even in the initially negative cases) along with aggressive combined multimechanistic immunotherapies is the key in improving outcomes.Conclusion:A high index of suspicion in appropriate clinical circumstances and early aggressive immunomodulation might lead to a better outcome.