Nonconvulsive Status Epilepticus on Electroencephalography in a Case With Subacute Sclerosing Panencephalitis

Subacute sclerosing panencephalitis is a neurodegenerative disease with a poor prognosis. We report a case of a 5 1/2-year-old boy who had emotional lability, cognitive difficulties, and myoclonia after a mild closed head injury. The magnetic resonance image of the brain and computed tomographic scan of the head were normal. His electroencephalogram (EEG) showed continuous nonconvulsive status epilepticus activity, which could not be suppressed with intravenous diazepam. After treatment with phenytoin for 2 days, an EEG showed periodic high-amplitude sharp-and-slow-wave complexes, which were also not suppressed with intravenous diazepam. Since the patient had measles at 5 months of age, subacute sclerosing panencephalitis was considered, and the diagnosis was confirmed by the presence of measles antibodies in cerebrospinal fluid.