Clinical features of 11 patients with opsoclonus-myoclonus syndrome diagnosed in an urban pediatric institution in Mexico City: A retrospective study

Abstract

Background: Opsoclonus-myoclonus syndrome (OMS) is an immune-mediated disorder that affects the central nervous system. It is recognized as a paraneoplastic syndrome highly associated with neuroblastic tumors. In Mexico, accurate epidemiological data are lacking and there are no well-structured protocols aimed at standardizing a treatment regimen in patients with OMS. Aim: This study aims to describe the clinical features, etiological factors, and treatment related to OMS in Mexican children. Patients and Methods: A retrospective study was performed over a 10-year period (2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016), using the database of the "Hospital Infantil de México Federico Gómez". The patients were divided into two groups (tumor vs. no tumor) to determine if there were significant demographic differences between the subgroups. The demographic variables were compared between groups using the Student's t-test. Results: Eleven patients were identified. The median age at the onset of the first clinical manifestation was 23 ± 14 months and the median age at diagnosis was 26 ± 15 months. The time delay between the onset of symptoms and diagnosis was approximately 3 months. Conclusion: In Mexico, there is a paucity of experience regarding the clinical presentation of OMS, and due to the infrequency of this condition, it is rarely diagnosed in our population since most pediatricians are unaware of the existence of the syndrome. The findings of this paper are consistent with the previous studies in terms of a closely equal sex ratio, predominance of Stage I tumors, a greater number of female patients with a paraneoplastic etiology, high relapse rates, and frequent neuropsychiatric morbidity.