High dose pulsatile dexamethasone therapy in children with opsoclonus-myoclonus syndrome.

Opsoclonus-myoclonus syndrome (OMS) is a rare movement disorder characterized by chaotic eye movements, myoclonus, and ataxia associated with severe irritability. Different treatment modalities including steroids and cyclophosphamide have been tried in the past often with significant side effects and variable success. Here we present 11 children, diagnosed with OMS between 1999 and 2005 and treated with high dose dexamethasone pulses. Main symptoms at presentation were opsoclonus (11/11), ataxia and/or myoclonus (11/11), irritability (10/11) associated with a neuroblastoma in four children. Number of dexamethasone pulses ranged from 6 to 60 pulses. No major side effects were reported. In 6/11 children a complete and sustained remission of OMS symptoms was achieved after 6 to 29 pulses of dexamethasone. Two children from this group have a normal development and no neurological sequelae. Two further children have minor delays in fine- and gross-motor skills. Two children despite a complete recovery of OMS symptoms have persisting developmental problems. 5/11 children still require regular dexamethasone pulses in addition to daily prednisolone (n = 1) or have received cyclophosphamide pulses meanwhile (n = 2). All children continue to have developmental and neurological difficulties. In summary treatment with high dose pulsatile dexamethasone appears to be safe and beneficial in a subgroup of patients with OMS.