Subacute sclerosing panencephalitis (SSPE) is a chronic progressive encephalitis that develops a few years after measles infection and presents with a demyelination of the cerebral cortex.
Due to the measles immunization, nowadays cases of SSPE are very rare. In the United States, less than 10 cases/year are reported. However, in some countries like India, over 20 cases/per million people/per year are reported. Males are more often affected than females (3:1).
SSPE occurs primarily in children and young adults, approximately 2-8 years after the initial infection. Patients present with a history of measles infection (though the person seems to have fully recovered from the illness). Motor regression, cognition decline and seizures (focal, generalized tonic-clonic or myoclonic) are the major clinical manifestations. The electroencephalographic (EEG) pattern is characterized by periodic complexes that are disease-specific (generalized bisynchronous and symmetrical slow waves of high amplitude and a long repetition interval). Myoclonus, ataxia, autonomic dysfunction and dementia gradually develop. Stupor and coma precede the death. Histopathological findings in brain biopsy or autopsy include perivascular cuffing, eosinophilic cytoplasmic inclusions, neurophagia, and fibrous gliosis.
SSPE is caused by a mutant measles virus that provokes persistent brain inflammation (swelling and irritation).
Diagnosis is based on a detailed history, clinical examination, typical EEG and presence of antimeasles antibodies in the cerebrospinal fluid. Computing tomography or magnetic resonance imaging are used to detect the brain lesions and help the differential diagnosis.
A wide variety of neurological conditions should be considered in the differential diagnosis of SSPE: Creutzfeldt-Jacob disease, anoxic encephalopathy, metabolic encephalopathy, hepatic failure, drug toxicity, thyrotoxicosis, progressive myoclonic epilepsy.
At present, no curative therapy for SSPE is available. Immunization against measles is the only known prevention. Some patients that respond to antiviral drugs (ribavirin, amantadine) need to receive this treatment for the rest of their lives.
SSPE has a progressive course and results in premature death, usually within 1-4 years after disease onset.
Last update: October 2008