How serious is Progressive Multifocal Leukoencephalopathy?
Prognosis of Progressive Multifocal Leukoencephalopathy: Poor. Progressive debilitation. Commonly death within 1-4 years. Prognosis of Progressive Multifocal Leukoencephalopathy: The course of PML is relentlessly progressive. Death usually occurs between 1 and 4 months after onset; but there have been a number of reported cases with survival for months to years.