Reassessment of phenytoin for treatment of late stage progressive myoclonus epilepsy complicated with status epilepticus.

In order to find an effective treatment option for status epilepticus in progressive myoclonus epilepsy (PME), we reviewed the clinical course of 9 patients with PME. Initially, epilepsy was successfully treated with antiepileptics. However, it gradually became refractory to medication, and status epilepticus emerged 3-19 years after the onset of epilepsy. In these patients, status epilepticus in PME was classified into (1) myoclonic status epilepticus (MSE), (2) myoclonic-generalized status epilepticus (MGSE), and (3) generalized status epilepticus (GSE). MSE was common in patients with neuronal ceroid lipofuscinosis, and GSE was common in those with dentatorubral-pallidoluysian atrophy. MGSE was characterized by the mixture of escalating myoclonus and generalized seizures, and was observed in patients with Gaucher disease or unspecified PME. All patients were often refractory to infusion of benzodiazepines and barbiturates but phenytoin was able to terminate status epilepticus in 7 patients. Oral phenytoin administration as preventive therapy was effective in 6 patients. Aggravation of myoclonus was not provoked by these treatments. We propose that phenytoin should be considered as a treatment choice for PME patients at late stages to prevent the detrimental effects of prolonged or repeated status epilepticus on the brain tissues.