Progressive multifocal leukoencephalopathy (PML) is a rare infection that damages the material (myelin) that covers and protects nerves in the white matter of the brain.
The John Cunningham virus, or JC virus (JCV) causes PML. By age 10, most people have been infected with this virus though it hardly ever causes symptoms. But, people with a weakened immune system are at risk of developing PML. Causes of a weakened immune system include:
Symptoms may include any of the following:
The health care provider will perform a physical exam and ask about symptoms.
Tests may include:
In people with HIV/AIDS, treatment to strengthen the immune system can lead to recovery from the symptoms of PML. No other treatments have proved effective for PML.
PML is a life-threatening condition. Depending on how severe the infection is, up to one half of people diagnosed with PML die within the first few months.Talk to your provider about care decisions.
Reviewed By: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.