Remarkable improvement in progressive multifocal leukoencephalopathy following acute pyelonephritis with bacteremia.

Progressive multifocal leukoencephalopathy (PML) is caused by John Cunningham (JC) virus in immunocompromized patients such as those with human immunodeficiency virus (HIV) infection, hematological malignancy, autoimmune disorder, and immunodeficiency disorder as well as those undergoing chemotherapy or immunosuppressive therapy. No effective treatments have been established for PML, which commonly causes severe neurological sequelae. We describe the first case of PML in a patient without HIV infection who exhibited remarkable improvement following acute pyelonephritis with Escherichia coli bacteremia.