Acute fulminant subacute sclerosing panencephalitis in two patients: Dual viral hit hypothesis

Abstract

Subacute sclerosing panencephalitis (SSPE) is a rare lethal neurological disorder caused by persistent mutant measles virus (MV) in central nervous system. Usually affected individuals have a positive history of measles infection in infancy phase. The disease is characterized by progressive cognitive decline, deterioration in motor functions, repeated myoclonus finally leading to vegetative state and death. Commonly, SSPE patients manifest clinically after 2-10 years of intervening gap from primary measles infection. In last few years, atypical presentations of subacute sclerosing panencephalitis have been reported, many patients initially presenting with vision loss. Why only some patients developed SSPE after long gap of primary measles infection? Various immunological mechanisms have been hypothesized. It has been proven that subacute sclerosing panencephalitis patients failed to form adequate antibodies to measles virus M (matrix) protein despite an appropriate response to other viral proteins. In this case report, we hypothesized that viral co-infections could lead to immune abnormalities and immunosuppression resulting into acute fulminant subacute sclerosing panencephalitis. We presented two patients of subacute sclerosing panencephalitis, one patient preceded by dengue virus infection and other by varicella zoster infection.