• Progressive Multifocal Leukoencephalopathy



    PML is a rare progressive disease of the nervous system. It is caused by a viral infection of the cells that produce myelin.
    The Neuron
    Nucleus Image
    Copyright © Nucleus Medical Media, Inc.


    PML is caused by a specific papovavirus, known as JC virus. Many people get this infection in childhood. It produces no illness and generally does not infect the nervous system. It reactivates later in life in people who have suppressed immune systems. The virus damages oligodendrocytes, the cells in the central nervous system (CNS) which produce myelin, the material that wraps around nerves. This impairs nerve function.

    Risk Factors

    PML is most common in people with suppressed immune systems. Suppressed immune systems may be the result of:
    • HIV/AIDS (most common)
    • Leukemia and lymphoma
    • Organ transplant
    • Cancer
    • Chronic steroid therapy
    • Rare inherited immunodeficiencies
    • Certain medications, such as natalizumab, a medication used to treat multiple sclerosis (MS)


    Symptoms progress over weeks and may include:
    • Vision problems
    • Speech pronunciation problems
    • Coordination loss
    • Memory loss
    • Weakness in limbs
    • Behavioral changes
    • Changes in thinking
    • A loss of language capability— aphasia
    • Seizures
    • Sensory loss


    Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include:
    • MRI scan —used to take images of brain structures (key in the diagnosis)
    • Lumbar puncture —to evaluate cerebrospinal fluid
    • Blood and urine tests
    • Brain biopsy


    Treatment focuses on strategies to improve the immune system. If you have HIV, your doctor will most likely prescribe antiretroviral medications to treat this condition. If PML has resulted from the drug natalizumab, your doctor will have you stop taking this drug and may recommend a plasma exchange to remove the drug from your blood system.


    There are no current guidelines to prevent exposure to the JC virus. If you have a suppressed immune system, get treatment to minimize your risk.


    AIDS Information, Education, Action, Awareness http://www.aids.org

    National Organization for Rare Disorders http://www.rarediseases.org


    Canadian AIDS Society http://www.cdnaids.ca

    Canadian Organization for Rare Disorders http://www.cord.ca


    Progressive multifocal leukoencephalopathy (PML). AETC National Resource Center website. Available at: http://aidsetc.org/resource/progressive-multifocal-leukoencephalopathy-pml. Updated May 1, 2013. Accessed June 2, 2014.

    NINDS progressive multifocal leukoencephalopathy information page. National Institute of Neurological Disorders and Stroke website. Available at http://www.ninds.nih.gov/disorders/pml/pml.htm. Updated February 14, 2014. Accessed June 2, 2014.

    Progressive multifocal leukoencephalopathy. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated October 1, 2013. Accessed June 2, 2014.

    Warnke C, Menge T, Hartung HP, et al. Natalizumab and progressive multifocal leukoencephalopathy: what are the causal factors and can it be avoided? Arch Neurol. 2010;67(8):923-930.

    Revision Information

  • LiveWell personal health survey

    How healthy are you really? Find out – free.Learn more

    It's time to stop guessing. If you want to make some changes but just aren't sure how, the free personal health survey from LiveWell is a great place to start.

  • HeartSHAPE Spotlight

    At risk for a heart attack? Learn more

    Fight heart disease and prevent heart attacks. HeartSHAPE® is a painless, non-invasive test that checks pictures of your heart for early-stage coronary disease.

  • Calories and Energy Needs

    Calorie NeedsLearn more

    How many calories do you need to eat each day to maintain your weight and fuel your physical activity? Enter a few of your stats into this calculator to find out.

  • Ideal Body Weight

    Ideal Body WeightLearn more

    Using body mass index as a reference, this calculator determines your ideal body weight range. All you need to do is enter your height.

  • Body Mass Index

    Body Mass IndexLearn more

    This tool considers your height and weight to assess your weight status.

  • Can we help answer your questions?

    Wellmont Nurse Connection is your resource for valuable health information any time, 24 hours a day, seven days a week. Speak to a Nurse any time, day or night, at (423) 723-6877 or toll-free at 1-877-230-NURSE.