PML is a rare progressive disease of the nervous system. It is caused by a viral infection of the cells that produce myelin.
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PML is caused by a specific 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 suppressed immune systems.
The virus damages myelin, the material that wraps around nerves. This impairs nerve function.
PML is most common in people with supressed immune systems. Supressed immune systems may be the result of:
Organ transplantCancerChronic steroid therapyRare inherited immunodeficiencies
Certain medications, such as
natalizumab, a medication used to treat
Symptoms progress over weeks and may include: Vision problemsSpeech pronunciation problemsCoordination lossMemory lossWeakness in limbsBehavioral changesChanges
—a loss of language capability
Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include: MRI
—used to take images of brain structures (key in the diagnosis)
Lumbar punctureBlood and urine tests
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
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.
National Institute of Neurological Disorders and Stroke. Progressive multifocal leukoencephalopathy information page. National Institute of Neurological Disorders and Stroke website. Available at
. Updated September 27, 2011. Accessed July 11, 2013.
Warnke C, Menge T, Hartung HP, et al. Natalizumab and progressive multifocal leukoencephalopathy: what are the causal factors and can it be avoided?
Last reviewed July 2013 by Rimas Lukas, MD; Brian Randall, 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.
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