Subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a slowly progressing central nervous system (CNS) disease of children and young adolescents with an average age of onset of about 7 years. It usually begins with insidious behavioral changes and a decline in intellectual functions, followed in weeks or months by definite neurologic signs, such as myoclonic jerks and incoordination. As the disease progresses there is further intellectual deterioration, which leads to a complete loss of cerebral function. SSPE usually lasts from a few months to 1-2 years, but more chronic forms occur, and duration of over 10 years has been reported. The histopathological lesions are found in the white as well as in the grey matter of the CNS and consist of perivascular infiltration of lymphocytes, widespread gliosis, demyelination, and eosinophilic nuclear and cytoplasmic inclusion bodies in neurons and glial cells. Immunologically, SSPE is characterized by a marked increase in the gamma globulin concentration in sera and spinal fluids of patients. As first shown by Lowenthal and coworkers (1) the gamma globulin contains one or more homogeneous bands in agar gel electrophoresis. A viral etiology of SSPE was suggested in early studies of the disease, because of the type of histological changes in the CNS, particularly the intranuclear inclusion bodies in neurons and glia.