neurologic disorders
Progressive Multifocal Leukoencephalopathy (PML)
Introduction
Progressive multifocal leukoencephalopathy (PML) is caused by reactivation of the JC virus. The disease usually occurs in patients with impaired cell-mediated immunity, particularly patients with HIV infection. PML results in subacute and progressive demyelination in the central nervous system, multifocal neurologic deficits, and death, usually within 9 months. Diagnosis is with MRI plus cerebrospinal fluid analysis using polymerase chain reaction testing. In AIDS patients, highly active antiretroviral therapy may slow down the progression, and patients taking immunosuppressants may improve when those drugs are withdrawn. Limited data suggest that treatment with immune checkpoint inhibitors, which activate the immune response to the JC virus, is sometimes helpful. Treatment is otherwise supportive. (See also Introduction to Brain Infections .) 