Subacute Sclerosing Panencephalitis

Infectious Causes of Dementia

Subacute Sclerosing Panencephalitis

Subacute sclerosing panencephalitis is an infectious cause of de-mentia that usually appears in childhood. The average age at onset is 10 years, and most patients are male and live in rural areas. It is diagnosed on the basis of periodic complexes on the EEG and an elevated measles titer in the cerebrospinal fluid (CSF). The CT scan shows cerebral atrophy and dilated ventricles. Myoclonus and dementia are prominent features.

It has been postulated that a mutant measles virus is the infectious agent, based on the high CSF measles antibody titer and the fact that the disease is virtually nonexistent in children who have been vaccinated for measles. Affected patients show an insidious onset of impairment of cognition usually preceded by behavioral problems.