Neuroprogressive disease of post-infectious origin: a review of a resurging subacute sclerosing panencephalitis (SSPE)

Subacute sclerosing panencephalitis (SSPE) is a progressive, essentially untreatable, disease of the nervous system. When first described in the 20th Century, it was characterized more for its neuropathological features than for its pathophysiology or cause. It was not until the 1960s that a clear relationship to the measles virus was established. It is now thought that this uncommon infectious encephalopathy is caused by a "slow," altered or persistent form of the wild measles virus which has harbored in the nervous system for years. Then a "breakout" occurs and the more lytic and virulent organisms produce the progressive and spreading inflammatory and destructive lesions which are confined to the nervous system. Epidemiological study of the disease confirms its relationship to measles. In the years since the development of national measles immunization programs, there has been a dramatic decline in the incidence of measles exanthem and until recently a corresponding decline in the incidence of SSPE. In recent years there has been a mild to moderate increase in cases of SSPE as reported to the USA/International SSPE Registry. As yet, there has not been a totally effective treatment. The purpose of this paper is to give an overall review on SSPE and its relationship to measles. This review will include a prospectus of its history, considerations as to its etiology, correlation of clinicopathological features, and thoughts on the past and present epidemiology and treatment.