[Opsoclonus-myoclonus syndrome]

The opsoclonus-myoclonus syndrome in children is a rare entity which is characterized by irritability, chaotic ocular movements with vertical, horizontal, rotatory components (opsoclonus) along with myoclonus and ataxia. In a high proportion of cases, it is associated with neuroblastoma although other etiologies involving infectious or toxic agents have been reported. An autoimmune mechanism would be responsible for the dysfunction of structures in brain stem and cerebellum thus explaining some of the cardinal symptoms such as opsoclonus, myoclonus and ataxia. However, encephalopathic symptoms and the high percentage of patients with neurocognitive and psychiatric sequels are in favor of a wider dysfunction. Treatment with steroids, ACTH, immunomodulatory or immunosuppressive drugs is being used although prospective studies are needed to determine whether the prolonged use of these drugs influences favorably the evolution of these patients.