Adult-onset opsoclonus-myoclonus-ataxia syndrome: clinical features and diagnostic findings

Abstract

Background: Opsoclonus-myoclonus-ataxia (OMA) is a rare neurological disorder characterized by the presence of abnormal saccadic ocular movements, ataxia and myoclonus. OMA is an autoimmune disease probably caused by a dysfunction in Purkinje cells secondary to an altered humoral and cellular response. The most frequent etiologies in adults are paraneoplastic, idiopathic and parainfectious. Objective: to describe two cases of opsoclonus-mioclonus-ataxia. Patients and methods: We reviewed the clinical history and diagnostic tests of two patients from December 2012 to April 2015. Case one: 32 year/old woman who, a week after a gastroenteritis, started suddenly with opsoclonus, ataxia and generalized myoclonic jerks. Case two: 60 year/old man who, after flu-like syndrome, started suddenly with generalized myoclonus, ataxia and opsoclonus. Results: Both patients were studied in the same way. In table one we show the results of diagnostic tests performed.Tabled 1Case 1Case 2Brain MRINormalNormalEBV, VZV, HSV PCRNegativeNegativeHIV serologyNegativeNegativeAnti-Hu, anti-Yo, anti-Ri antibodiesNegativeNegativeRoutine laboratory test and CSF analysisNormalNormalWhole-Body FDG-PET scanRight cortical hypometabolismLeft cortical hypometabolism Open table in a new tab They were diagnosed as idiopathic OMA, received steroid therapy and had a good outcome. Conclusion: As in the patients we describe, an important number of idiopathic cases are preceded by infectious symptoms without confirmation of an infectious cause. Even though both patients presented typical features of idiopathic OMA, the result of both PET scans showed cortical unilateral cortical hypometabolism without cerebellar involvement, which is not usual in this syndrome.