Cytomegalic inclusion body disease

Definition

Cytomegalic inclusion body disease (CIBD) is a condition caused by infection with cytomegalovirus (CMV), a type of herpes virus. A hallmark of CIBD is the periodic reappearance of symptoms throughout life, as the virus cycles through periods of latency and active infection.

Description

CMV is one of the members of the herpes virus group, which includes herpes simplex types 1 and 2, and the viruses that cause chicken pox and infectious mononucleosis. The virus causes enlargement of cells of some organs and the development of inclusion bodies—bits of cellular material—in the cytoplasm or nucleus of these cells. A hallmark of the virus group is the ability to infect a host and then become dormant. CMV can remain dormant for years. Even in periods without symptoms, the

virus can still be periodically shed from the body in fluids like tears, saliva, blood, semen, and breast milk. The virus can infect another person through close contact.

Many people with CMV can harbor the virus and display no symptoms. However, if the immune system is damaged or otherwise not functioning efficiently, the virus can reactivate from its dormancy. Cytomegalic inclusion body disease is also known as giant cell inclusion disease, cytomegalovirus infection, and salivary gland disease.

Demographics

The latent infection caused by CMV occurs virtually all over the world and is very common in any population. In the United States, up to 50–85% of people will be infected by the age of 40. CMV infection without symptoms is common in infants and young children. CMV infection is most widespread in economically debilitated regions, although people in developed countries are also susceptible.

Additionally, the virus can be readily transferred from a pregnant mother to the fetus. An infected pregnant woman may not display any symptoms. However, the fetus of a mother with CIBD is at risk for problems, including lung disease, bleeding, anemia, liver damage, or brain damage. CIBD is also a problem among those whose immune systems are not functioning properly or have not yet matured. This includes the unborn, people infected with the human immunodeficiency virus (HIV), and those whose immune systems have been deliberately disabled (i.e., organ transplant recipients).

Causes and symptoms

The cytomegalovirus is the cause of CIBD. When the infection occurs in healthy people after birth, symptoms can be minimal or even nonexistent. Some people experience mild symptoms similar to those of mononucleosis, including a prolonged fever, fatigue , mild hepatitis, and tender lymph nodes.

In a fetus, newborn, or a person with a compromised immune system, CIBD can be much more severe. With CIDB, people suffering from acquired immunodeficiency syndrome (AIDS ) or people recovering from kidney and or other transplant surgeries can also develop inflammation of the retina of the eyes (retinitis) or encephalitis. Retinitis is more common, and in severe cases, blindness can result.

CIBD can cause death of a fetus or a premature birth. In infected newborns, CIBD can be apparent as a lung infection, excessive bleeding, anemia, liver damage, enlargement of the spleen, seizures , and inhibited brain development. The latter can result in hearing loss, developmental delays, and difficulty in coordination.

CMV-related polyradiculopathy also causes leg weakness, bowel dysfunction, and bladder dysfunction in end-stage AIDS patients suffering CMV infection.

Diagnosis

Diagnosis is based on the detection of the symptoms of CIBD. Because symptoms can be absent, diagnosis is often overlooked or difficult. If the virus is actively dividing, antibodies to the virus may be detectable by immunological tests of the blood such as the enzyme-linked immunosorbant assay (ELISA). As the antibodies persist for life, their detection is not a guarantee of an ongoing infection. The virus can also be isolated from urine and other body fluids.

One diagnostic feature associated with retinitis is the description of moving black spots in the eye. Although these "floaters" are common even in healthy individuals, they can also be the result of inflammation of the retina, and can alert a physician to the possibility of CIBD.

Treatment team

Treatment is usually maintained by the primary care physician for otherwise healthy patients. For those who are deliberately immunocompromised, newborns, and AIDS patients, a battery of specialists, including immunologists and specialists in infectious disease, can be involved in treatment and care.

Treatment

There is no cure for CIBD. Typically, good hygiene, including proper hand washing, is recommended to avoid transmission of the virus from person to person. Antiviral drugs such as ganciclovir and acyclovir can be administered, particularly to AIDS patients to reduce the amount of virus in the body. These drugs are taken throughout life. There are no vaccines for CIBD.

Recovery and rehabilitation

The CMV infection persists throughout life, therefore, rehabilitation efforts focus on supportive measures to combat CMV-caused complications, minimize the effect of symptoms, and minimize the possibility for transmission of the virus.

Clinical trials

As of February 2004, there are no specific CIBD clinical trials underway.

Prognosis

Most people who are infected with CMV display no symptoms and have no residual effects of the infection. However, in immunocompromised people, newborns, and unborn babies, the infection can cause serious illness or death.

Resources

BOOKS

Parker, J. N., and P. M. Parker. The Official Patient's Sourcebook on Cytomegalic Inclusion Body Disease. A Revised and Updated Directory for the Internet Age. San Diego: Icon Health Publications, 2003.

OTHER

Cytomegalic Inclusion Body Disease Information Page. National Institute of Neurological Disorders and Stroke. (May 20, 2004). <http://www.ninds.nih.gov/health_and_medical/disorders/cytomegalic.htm>.

Cytomegalovirus (CMV). New Mexico AIDS InfoNet. (May 20, 2004). <http://www.thebody.com/nmai/cmv.html>.

Cytomegaolavirus (CMV) Infection. Centers for Disease Control and Prevention. (May 20, 2004). <http://www.cdc.gov/ncidod/diseases/cmv.htm>.

ORGANIZATIONS

Centers for Disease Control and Prevention (CDC). 1600 Clifton Road, Atlanta, GA 30333. (404) 639-3311 or (800) 311-3435. <http://www.cdc.gov>.

National Institute of Allergy and Infectious Disease (NIAID). 31 Center Drive, Rm. 7A50, MSC 2520, Bethesda, MD 20892-2520. (301) 402-1663; Fax: (301) 402-0120. [email protected]. <http://www.ninds.nih.gov>.

National Institute for Neurological Diseases and Stroke (NINDS). 6001 Executive Boulevard, Bethesda, MD 20892. (301) 496-5751 or (800) 352-9424. <http://www.ninds.nih.gov>.

Brian Douglas Hoyle, PhD