81. : Adult onset opsoclonus-myoclonus with autonomic dysfunction responsive to intravenous immunoglobulin

We describe a case of idiopathic adult onset opsoclonus-myoclonus syndrome with autonomic dysfunction, and review the clinical features and management of this rare condition. A 23-year-old woman was admitted to a regional hospital in NSW, Australia with opsoclonus-myoclonus syndrome (OMS) and moderate ataxia following a recent influenza-like illness, complicated by autonomic dysfunction. Intensive diagnostic assessment revealed no evidence of a remote neoplasm, and para-infectious OMS was felt the most probable diagnosis. Admission was complicated by autonomic dysfunction requiring critical care unit admission. The symptoms responded to treatment with high dose intravenous Ig (IVIG) and methylprednisolone. Apart from elevated influenza A antibodies, serological tests did not confirm a recent infection. Diagnosis was made of idiopathic OMS. OMS is a rare autoimmune central nervous system disorder in adults. Both parainfectious and paraneoplastic causes must be considered. Autonomic dysfunction in idiopathic OMS is unusual, and is usually associated with identified paraneoplastic antibodies such as NMDA receptor antibodies. As demonstrated in our patient, IVIG and corticosteroids are effective first line therapies in the management of parainfectious or idiopathic OMS with complete recovery.