AIDS InfoNet Logo
This website is certified by Health On the Net Foundation. Click to verify.
This site complies with the HONcode standard for trustworthy health information:
verify here.

The Henry J. Kaiser Family Foundation
Site of the Week
November 2003

The Health Leader Award 2006
The Health Leader Award 2006

The HOPE Reward

Med411.com Medical Award

HealthAtoZ.com Featured Site Award

BuscaSalud.com

IBS Tales Hope Award

HealingWell.com Editor's Choice Award

Listed in Listed in Treasures of the Internet


AIDS InfoNet Logo.  The AIDS InfoNet - Reliable, Up-to-Date AIDS Treatment Information
International Association of Providers of AIDS Care
Reviewed April 16, 2014

Fact Sheet 516

Progressive Multifocal Leucoencephalopathy (PML)


WHAT IS PML?
HOW CAN PML BE DETECTED?
HOW IS PML TREATED?
THE BOTTOM LINE
 


WHAT IS PML?

Progressive multifocal leucoencephalopathy is a serious viral infection of the brain.

“Encephalo” means brain. “Pathy” means disease. Encephalopathy is a disease of the brain. “Leuco-” (or "leuko") means pale or white. Leucoencephalopathy is a disease of the white matter of the brain.

“Progressive” means that this disease gets worse in a short time. “Multifocal” means that it shows up in several places at the same time.

Researchers estimate that about 6% of people with AIDS develop PML. Most cases of PML show up in people with CD4 cell counts below 100. The exact rate is hard to know because PML is difficult to diagnose.

Most cases of PML used to be fatal. People diagnosed with PML lived an average of 6 months, and most died within 2 years. However, if people with PML start taking strong antiretroviral medications (ARVs) to control their HIV, they can survive much longer. Now more than half of people with HIV and PML survive for at least two years.

The “JC” virus causes PML. Between 80–85% of all adults are exposed to this virus worldwide. In people with weakened immune systems, JC virus can become active.

 


 HOW CAN PML BE DETECTED?

The first symptoms of PML are weakness or coordination problems in an arm or leg. There may be difficulty thinking or speaking. Vision and memory problems, seizures, and headaches can occur.

These symptoms can also occur with other opportunistic infections, including toxoplasmosis, lymphoma, inner ear infections, or cryptococcal meningitis. It is important to rule out these other diseases.

PML can be diagnosed using a scan of the brain by magnetic resonance imaging (MRI). Another way to test for PML is by checking spinal fluid. The sample is taken by inserting a needle into the spinal canal. This procedure is called a spinal tap.

 


 HOW IS PML TREATED?

A major problem with treating any brain infection is the “blood-brain barrier.” The blood vessels around the brain are different from the rest of the body. They are “tightly woven” to protect the brain from toxic substances. Chemicals that dissolve in fat can get through. Those that dissolve in water can’t. Unfortunately, this includes most antibiotics and many other medications.

There is currently no proven treatment for PML. Research studies have had conflicting results. Some possible treatments have not been carefully studied. However, PML has slowed down or stopped in some patients taking strong ARVs to fight HIV.Strengthening the immune system is currently the best way to treat PML. This approach might trigger immune reconstitution inflammatory syndrome (IRIS, see fact sheet 483.)

Ara-C (Cytosine arabinoside or cytarabine) has been tried against PML. It was given intravenously, or pumped directly into the brain. It seemed to work in one small study, but not in later ones. Ara-C is very toxic, and damages bone marrow.

High-dose AZT has been tried against PML, because it crosses the blood-brain barrier. Other substances that have been tried with different degrees of success include acyclovir, heparin, peptide-T, beta interferon, dexamethasone, mefloquine, n-acetylcysteine, topotecan and cidofovir.

Because PML can progress rapidly, it is important to begin treatments quickly.

 


 

 THE BOTTOM LINE

PML is a viral infection of the brain caused by the JC virus. It is fatal in about 50% of cases. It can be confused with other medical conditions.

There is no approved treatment for PML, although several treatments may be helpful. Strengthening the immune system using antiretroviral therapy is currently the best approach. Any treatment must be started as early as possible. Combination antiretroviral therapy (ART) may slow the progress of PML.

 


 

 


Back to Fact Sheet Categories



New Mexico AIDS Education and Training Center The University of New Mexico Health Sciences Center International Association of Providers of AIDS Care

 

The AIDS InfoNet is a project of the New Mexico AIDS Education and Training Center at the University of New Mexico Health Sciences Center,
and the International Association of Providers of AIDS Care.
webmaster@aidsinfonet.org

 

United States National Library of Medicine

Partially funded by the National Library of Medicine



Search Our Site
Newest Fact Sheets
Print This Fact Sheet
You can print this fact sheet on a single page in Microsoft Word (.doc) format or Adobe Acrobat (.pdf) format. Click on the links below to open the document in your browser and then print it.
 Adobe Acrobat PDF
 Microsoft Word

You can print directly from your browser using the link below. The printout will probably go onto a second page.
 Print Version (Web)

Monthly E-mail Updates

The InfoNet updates its Fact Sheets frequently. A listing of each month's changes is posted to several e-mail lists.

If you would like to receive this monthly update by personal e-mail, please provide your e-mail address below, and click on the "Submit" button.



Subscribe
Unsubscribe