Progressive multifocal leukoencephalopathy

  • Definition
    • 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.

  • Alternative Names
    • PML; John Cunningham virus; JCV

  • Causes
    • The John Cunningham virus, or JC virus (JCV) causes PML. By age 10, most people have been infected with this virus. But 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 now because of better AIDS treatments).
      • 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 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:

  • 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's 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. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 147.