Step-Up Immunotherapy in Pediatric Opsoclonus–myoclonus Syndrome

Opsoclonus–myoclonus syndrome (OMS) is a rare, immune-mediated pediatric neurological disorder characterised by chaotic multidirectional eye movements, myoclonic jerks, ataxia, and behavioural disturbances. It is frequently associated with neuroblastoma and may lead to long-term neurodevelopmental complications if not diagnosed and treated promptly. We report the case of a 3-year-1-month-old male child diagnosed with OMS who presented for routine follow-up and ongoing immunomodulatory therapy. The patient initially exhibited classical neurological features, with normal neuroimaging and negative neuroblastoma screening, supporting an autoimmune aetiology. Management included high-dose intravenous methylprednisolone and rituximab, along with supportive nutritional therapy and close monitoring for adverse drug reactions. The treatment was well tolerated, and the child remained clinically stable without infusion-related complications. Laboratory investigations revealed microcytic anaemia, managed with iron supplementation. OMS requires early recognition, comprehensive evaluation for underlying malignancy, and aggressive immunotherapy to reduce relapse risk and improve neurological outcomes. Long-term multidisciplinary follow-up and caregiver education are essential due to the chronic and relapsing nature of the disorder and its potential impact on cognitive and motor development.