Severe myoclonic epilepsy of infancy.

Severe myoclonic epilepsy of infancy (SMEI) is a recently identified seizure disorder with a uniformly poor prognosis. No successful therapy has been found for this disorder. Based on the treatment of 7 patients who qualified for the diagnosis in this report, SMEI has a better prognosis than recognized currently. All 7 patients were responding poorly to phenobarbital, phenytoin, or carbamazepine. Six of them responded to valproate. Two patients became seizure-free during valproate monotherapy. A succinimide was required as a second antiepileptic drug in 3 patients to achieve seizure control. Repeated episodes of "febrile status epilepticus" in 2 patients were controlled with lorazepam. Five of 7 patients are doing significantly better than the literature would suggest is possible. Seizure control can be achieved in SMEI with aggressive use of drugs which are beneficial for myoclonic seizures. Traditional drugs for tonic-clonic seizures are of little or no benefit in SMEI.