Enterovirus Induced Opsoclonus-Myoclonus Syndrome in a 16-Month-Old Girl

Background/Purpose: Opsoclonus-Myoclonus Syndrome (OMS) is a rare neurological disorder characterized by jerking conjugated bulbar movements, ataxia with myoclonus, and psychiatric symptoms. OMS results from various etiologies, including paraneoplastic, parainfectious, toxic-metabolic, and idiopathic causes. OMS can appear at any age, the average age of onset in children is 18 to 22 months.

Case Report: We report on a healthy 16 months old girl who presented with intention tremor and, within four days, generalized dystonia. Cranial MRI and cerebrospinal fluid (CSF) analysis excluded an intracranial tumor or disorders of dopamine metabolism. During the following 2 weeks the clinical condition worsened: the patient developed constant myoclonic jerks, severe ataxia, bobbing eye movements, and extreme irritability, resulting in the diagnosis of OMS. Therefore, a Neuroblastoma was excluded. Repeated CSF analysis showed persisting inflammatory changes, including positive oligoclonal bands. Virological analysis revealed an elevated specific antibody index of 20.1 for rubella IgG. Serum antibody testing and PCR ruled out acute viral infection. Due to positive CSF polymerase chain reaction for enterovirus, a parainfectious OMS was diagnosed. Two weeks after admittance, immunosuppressive therapy started with intravenous immunoglobulins monthly without substantial effect. Prednisolone was added after six weeks. The neurological status improved and four months after the initial symptoms this treatment led to a restitution ad integrum.

Conclusion: Outcome of OMS is often associated with long-term neurological morbidity and cognitive problems; however, early treatment with immunoglobulins and steroids seems to positively influence the neurological outcome.