Subacute sclerosing panencephalitis and chronic viral encephalitis.

Subacute sclerosing panencephalitis (SSPE) is a chronic infection of the central nervous system associated with the presence of mutant measles virus in the brain. It presents as a progressive, usually fatal disease. The diagnosis is based on clinical criteria and an elevated titer of measles antibodies in the cerebrospinal fluid (CSF). Electroencephalography and imaging studies provide supportive laboratory data. A brain biopsy is indicated only when CSF serology is negative or equivocal in a suspected case to assess the presence of inclusion bodies, measles virus antigens, or viral RNA. Among many drugs and methods tried in the treatment, the highest rate of stabilization or improvement was obtained with intraventricular human lymphoblastoid interferon-α and oral inosiplex. Further research for more available and efficient therapeutic regimens is warranted. Measles and SSPE are preventable by maintenance of high rates of immunization in the population.