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Progressive Multifocal Leukoencephalopathy

(PML)

Pronounced: LOO-koh-en-sef-ah-LOP-ah-thee

Definition

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

Causes

PML is caused by a papovavirus, known as JC virus. Most people get this infection in childhood, and it produces no illness. It reactivates later in life in people who have a suppressed immune system (eg, HIV/AIDS ).

Risk Factors

The most common risk factor is having HIV/AIDS. PML is rarely associated with:

Leukemia and lymphoma

Tuberculosis

Sarcoidosis

Prolonged immunosuppression (organ transplant or cancer patients)

Chronic steroid therapy

Rare inherited immunodeficiencies

Natalizumab (medicine used to treat multiple sclerosis )

Symptoms

If you experience any of these symptoms, do not assume it is due to PML. These symptoms may be caused by other conditions. Symptoms progress over weeks and include:

Vision problems

Speech pronunciation problems

Ataxia (loss of coordination)

Memory loss

Weakness in limbs

Behavioral changes

Cognitive changes

Aphasia (loss of language capability)

Seizures and headaches (rare)

Sensory loss

Diagnosis

Your doctor will ask about your symptoms and medical history. She will also do a physical exam. Tests may include:

MRI scan —a test that uses magnetic waves to make pictures of structures inside the brain (key in the diagnosis)

Spinal tap —removal of a small amount of cerebrospinal fluid to check for evidence of the JC virus in the brain

Blood and urine tests

Brain biopsy

Treatment

Treatment focuses on strategies to improve the immune system. If you have HIV, your doctor will most likely prescribe antiretroviral medicine 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.

Prevention

Most people have been exposed to this virus. If you have HIV/AIDS, get treatment to minimize your risk.

RESOURCES:

AIDS.org

http://www.aids.org/

National Organization for Rare Disorders

http://www.rarediseases.org/

CANADIAN RESOURCES:

Canadian AIDS Society

http://www.cdnaids.ca/

Canadian Organization for Rare Disorders

http://www.cord.ca/

References:

AETC National Resource Center. Progressive multifocal leukoencephalopathy. AETC National Resource Center website. Available at: http://www.aids-ed.org/aidsetc?page=cm-528_pml . Accessed November 10, 2010.

Greenlee JE, Roos RP. MedLink website. Available at: http://www.medlink.com . Accessed March 10, 2012.

National Institute of Neurological Disorders and Stroke. 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 10, 2012. Accessed March 10, 2012.

Progressive multifocal leukoencephalopathy. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Updated May 27, 2010. Accessed November 10, 2010.

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):923-30.

Last reviewed March 2013 by Rimas Lukas, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.