Progressive multifocal leukoencephalopathy
PML; John Cunningham virus; JCV
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.
The tissue called "gray matter" in the brain and spinal cord is also known as substantia grisea, and is made up of cell bodies. "White matter", or substantia alba, is composed of nerve fibers.
Progressive multifocal leukoencephalopathy is an advancing viral inflammation of the white matter of the brain. Immunosuppressed people are more susceptible to this disorder than the general population. Evidence of the disease may be a person's recent loss of coordination and weakness, progressing to a loss of language, visual problems and headaches.
Causes
The John Cunningham virus, or JC virus (JCV) causes PML. By age 10, most people have been infected with this virus though it hardly ever causes symptoms. But, people with a weakened immune system are at risk of developing PML. Causes of a weakened immune system include:
- HIV/AIDS (less common cause of PML now because of better management of HIV/AIDS).
- Certain medicines that suppress the immune system. Such medicines may be 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 test for the JCV
- CT scan of the brain
- Electroencephalogram (EEG)
- MRI of the brain
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.
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.
References
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. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 370.
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, Updated Edition. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 147.
Version Info
Last reviewed on: 2/27/2018
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.
