Management of opsoclonus-myoclonus-ataxia syndrome in children

OMAS: opsoclonus-myoclonus-ataxia syndrome; IVIG: intravenous immune globulin; MRI: magnetic resonance imaging; IV: intravenous; ACTH: corticotropin.

* OMAS is associated with neuroblastoma in approximately 50% of cases; symptoms of OMAS may precede discovery of the tumor. Screening protocol for neuroblastoma consists of:

• Chest, abdominal, and pelvic MRI
• Urinary vanillylmandelic acid and homovanillic acid
• ¹²³I-metaiodobenzylguanidine (MIBG, iobenguane I-123) scan if MRI results are unrevealing

Refer to UpToDate topic on diagnosis and staging evaluation of neuroblastoma for further details.

¶ A typical pulsed regimen consists of IVIG plus IV methylprednisolone given over the first 3 to 5 days of each month. Some centers prefer plasma exchange instead of IVIG and ACTH instead of glucocorticoids. Refer to UpToDate topic on OMAS for further details.

Δ The goal of initial immune suppression is to achieve maximal clinical response and sustained remission. Function should be assessed serially in multiple domains, including stance and gait, arm/hand function, opsoclonus, mood/behavior, and speech. Clinical remission is defined as normalization of walking and arm/hand function and resolution of opsoclonus; any residual abnormalities in mood, behavior, and speech should be mild.

◊ Cyclophosphamide is an alternative to rituximab for early add-on therapy. If cyclophosphamide is used initially, rituximab is used subsequently in patients with an insufficient response.