Successful treatment of encephalopathy and myoclonus with levetiracetam in a case of subacute sclerosing panencephalitis.

Subacute sclerosing panencephalitis is a devastating progressive degenerative disease of the nervous system presumably caused by a persistent measles virus. Patients commonly present with myoclonia or encephalopathy. There are currently no known curative therapeutic options or effective symptomatic therapy. We treated a 12-year-old boy with subacute sclerosing panencephalitis who presented with acute encephalopathy and myoclonus. Electroencephalogram showed characteristic generalized periodic discharges. Levetiracetam produced dramatic improvement in both myoclonus and encephalopathy. The improvement was clear within 4 days. The electroencephalogram pattern showed improvement as well. Levetiracetam is a promising symptomatic therapy in subacute sclerosing panencephalitis for both the myoclonus and the encephalopathy. In this patient, it also appeared to improve the electroencephalographic pattern. We suggest that the generalized periodic discharges associated with the myoclonus contributed to the patient's encephalopathy.