Progressive multifocal leukoencephalopathy

Definition

Progressive multifocal leukoencephalopathy (PML) is a rare disorder that damages the material (myelin) that covers and protects nerves in the white matter of the brain.

Causes

The JC virus (JCV) causes PML. By age 10, most people have been infected with this virus. But it hardly ever causes symptoms. Persons with a weakened immune system, though, are at risk of developing PML. Causes of a weakened immune system include:

AIDS (less common now because of better AIDS treatments)
Certain medicines used to treat multiple sclerosis, rheumatoid arthritis, and related conditions
Leukemia and lymphoma

Symptoms

Headaches
Loss of coordination, clumsiness
Loss of language ability (aphasia)
Memory loss
Vision problems
Weakness of the legs and arms that gets worse

Exams and Tests

Tests may include:

Brain biopsy (rare)
Cerebrospinal fluid test for the JCV
CT scan of the brain
Electroencephalogram (EEG)
MRI of the brain

Treatment

In people with AIDS, treatment to strengthen the immune system can lead to recovery from the symptoms of PML. No other treatments have proved effective for PML.

Outlook (Prognosis)

PML is a life-threatening condition. Talk to your doctor about care decisions.

Review Date: 2/27/2013
Reviewed By: Luc Jasmin, MD, PhD, Department of Neurosurgery, Cedars Sinai Medical Center, Los Angeles and Department of Anatomy, University of California, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.

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