Cytomegalovirus natural history, complications and prognosis

Template:Cytomegalovirus Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Natural History

Once a person becomes infected, the virus latently persists in the body for the person's life and can exhaust the immune system at old age, increasing risk of mortality from other diseases. Recurrent disease rarely occurs unless the person's immune system is suppressed due to therapeutic drugs or disease. Initial CMV infection, which may have few symptoms, is always followed by a prolonged, inapparent infection during which the virus resides in cells without causing detectable damage or clinical illness. Severe impairment of the body's immune system by medication or disease (see below) may reactivate the virus from the latent or dormant state.

Complications

For infants who are infected by their mothers before birth, two potential problems exist:

• Generalized infection may occur in the infant, and symptoms may range from moderate enlargement of the liver and spleen (Hepatosplenomegaly) (with jaundice) to fatal illness. With supportive treatment most infants with CMV disease usually survive. However, from 80% to 90% will have complications within the first few years of life that may include hearing loss, vision impairment, and varying degrees of mental retardation.
• Another 5% to 10% of infants who are infected but without symptoms at birth will subsequently have varying degrees of hearing and mental or coordination problems.

Primary CMV infection in the immunocompromised patient can cause serious disease. However, the more common problem is the reactivation of the latent virus. In patients with a depressed immune system, CMV-related disease may be much more aggressive. CMV hepatitis may cause fulminant liver failure.

Severe CMV can cause:

• Blindness
• Pneumonia
• Diarrhea
• Bleeding ulcers in the esophagus (windpipe) or intestines
• Inflammation of the brain (encephalitis)
• Seizures

Prognosis

However, the above complications appear to be almost exclusively associated with women who previously have not been infected with CMV and who are having their first infection with the virus during pregnancy. Even in this case, two-thirds of the infants will not become infected, and only 10% to 15% of the remaining third will have symptoms at the time of birth. There appears to be little risk of CMV-related complications for women who have been infected at least 6 months prior to conception. For this group, which makes up 50% to 80% of the women of child-bearing age, the rate of newborn CMV infection is 1%, and these infants appear to have no significant illness or abnormalities.

Infection with CMV is a major cause of disease and death in immunocompromised patients, including organ transplant recipients, patients undergoing hemodialysis, patients with cancer, patients receiving immunosuppressive drugs, and HIV-infected patients.