Progressive multifocal leukoencephalopathy
Progressive multifocal leukoencephalopathy (PML) is a rare infection that damages the material (myelin) that covers and protects nerves in the white matter of the brain.
Myelin
Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty ...
White matter of the brain
White matter is found in the deeper tissues of the brain (subcortical). It contains nerve fibers (axons), which are extensions of nerve cells (neuro...
Causes
The John Cunningham virus, or JC virus (JCV), causes PML. JCV is also known as human polyomavirus 2. By age 10, most people have been infected with JCV, but it rarely causes symptoms. The virus remains in the body, but normally is inactive and causes no problems. But people with a weakened immune system are at risk of developing PML. Causes of a weakened immune system include:
-
HIV/AIDS (less common now because of better management of HIV/AIDS).
HIV/AIDS
Human immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). When a person becomes infected with HIV, the ...
ImageRead Article Now Book Mark Article - Medicines that suppress the immune system called monoclonal antibodies. These medicines are used to prevent organ transplant rejection or to treat multiple sclerosis, rheumatoid arthritis and other autoimmune disorders, and related conditions.
- Cancers, such as leukemia and Hodgkin lymphoma.
Symptoms
Symptoms may include any of the following:
- Loss of coordination, clumsiness
- Loss of language ability (aphasia)
- Memory loss
- Vision problems
- Weakness of the legs and arms that gets worse
- Personality changes
Exams and Tests
The health care provider will perform a physical exam and ask about symptoms.
Tests may include:
- Brain biopsy (in rare cases)
- Cerebrospinal fluid and blood test for the JCV
-
CT scan of the brain
CT scan of the brain
A head computed tomography (CT) scan uses many x-rays to create pictures of the head, including the skull, brain, eye sockets, and sinuses.
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Electroencephalogram (EEG)
Electroencephalogram
An electroencephalogram (EEG) is a test to measure the electrical activity of the brain.
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MRI of the brain
MRI of the brain
A head MRI (magnetic resonance imaging) is an imaging test that uses powerful magnets and radio waves to create pictures of the brain and surrounding...
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Treatment
In people with HIV/AIDS, treatment to strengthen the immune system can lead to recovery from the symptoms of PML. No other treatments have proved effective for PML. Medicines to treat PML are being developed and may be available in the near future.
Outlook (Prognosis)
PML is a life-threatening condition. Depending on how severe the infection is, up to one half of people diagnosed with PML die within the first few months.Talk to your provider about care decisions.
Reviewed By
Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Berger JR, Nath A. Cytomegalovirus, Epstein-Barr virus, and slow virus infections of the central nervous system. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 346.
Tan CS, Koralnik IJ. JC, BK, and other polyomaviruses: progressive multifocal leukoencephalopathy (PML). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 144.
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