Rasmussen syndrome and long-term response to gamma globulin.

Rasmussen syndrome (RS) is a severe and progressive focal epilepsy of unknown etiology that leads to deterioration of motor and cognitive function. We report a 14-year-old girl who developed epilepsia partialis continua involving the left hand, mild hemiparesis, and secondarily generalized seizures. RS was confirmed by brain biopsy. The patient has been treated with intravenous gamma globulin every 4 months for 46 months. The clinical course throughout this time has been distinctly atypical for RS, with no progression in motor or cognitive deficits and rare secondarily generalized seizures. Although the mechanism for action for gamma globulin in RS is not known, an immunomodulatory role has been postulated. Evidence of an immunologically mediated process in RS and clinical experience with a growing number of patients who benefit from immunomodulatory therapy suggest that a systematic study of the efficacy of gamma globulin in comparison with other forms of medical therapy is warranted.