progressive multifocal leucoencephalopathy
Last reviewed 01/2018
Progressive multifocal leucoencephalopathy (PML) is a multifocal demyelinating disease of the brain's white matter.
PML is caused by reactivation of latent JC papova virus. It occurs in association with systemic illness in which cell-mediated and often, humoral immunity is depressed:
- AIDS
- immunosuppressive therapy
- sarcoidosis
- systemic lupus erythematosus
- lymphoma
Features include personality change, dementia, hemiparesis, cortical visual loss, and seizures.
Papova virus is evident in oligodendroglia on electron microscopy. CT and MRI reveal widespread multifocal damage to the white matter. Definitive diagnosis is made by brain biopsy. The virus can be isolated by inoculation on to glial tissue culture.
Antiviral agents have been unsuccessful. Death usually occurs within 3-6 months.