Subacute sclerosing panencephalitis (SSPE) is a viral syndrome caused by a defective measles virus. It predominantly affects children less than 12 years of age, boys more than girls. After natural measles infection, the incidence of SSPE is 5 to 10 cases per 1 million. After vaccine, the rate is less than 1 case per 1 million vaccine recipients.
SSPE has a gradual onset, with a full range of subtle to severe neuropsychiatric phenomena. Initial symptoms tend to be mild cognitive deficits. These can be followed by ataxia, myoclonic jerks, and seizures.
The CSF profile is usually normal except for marked elevation of CSF immunoglobulin. Oligoclonal IgG bands, representing antibodies specific to measles virus, can be demonstrated.
The EEG often shows widespread cortical dysfunction with a burst-suppression pattern of high-amplitude slow-wave or spike-and-slow-wave complexes occurring at a rate of every 4 to 20 seconds. These may be synchronous with or independent of myoclonic jerks.
MRI can reveal multifocal white-matter lesions.
Reviewed and revised March 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.
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