Cytomegalovirus infection

Cytomegalovirus infection


Also called generalized salivary gland disease and cytomegalic inclusion disease, cytomegalovirus (CMV) infection is caused by the cytomegalovirus, which is a deoxyribonucleic acid, ether-sensitive virus belonging to the herpes family. The disease occurs worldwide and is transmitted by human contact.
About four out of five persons older than age 35 have been infected with CMV, usually during childhood or early adulthood. In most of these people, the disease is so mild that it’s overlooked.

Clinical tip Be aware that CMV infection during pregnancy can be hazardous to the fetus, possibly leading to stillbirth, brain damage, and other birth defects or to severe neonatal illness.
TopCauses
CMV has been found in the saliva, urine, semen, breast milk, stool, blood, and vaginal and cervical secretions of infected persons. Transmission usually happens through contact with these infected secretions, which harbor the virus for months or even years.
The virus may be transmitted by sexual contact and can travel across the placenta of a pregnant woman, causing a congenital infection. Immunosuppressed patients, especially those who have received transplanted organs, run a 90% chance of contracting CMV infection. Recipients of blood transfusions from donors with positive CMV antibodies are at some risk. Pregnant women who develop mononucleosis should also be evaluated for CMV infection.
TopSigns and symptoms
CMV probably spreads through the body in lymphocytes or mononuclear cells to the lungs, liver, GI tract, eyes, and central nervous system, where it commonly produces inflammatory reactions.
Most patients with CMV infection have mild, nonspecific complaints, or none at all, even though antibody titers indicate infection. In these patients, the disease usually runs a self-limiting course.
Immunodeficient patients, such as those with acquired immunodeficiency syndrome (AIDS), and those receiving immunosuppressants may develop pneumonia or other secondary infections. AIDS patients may also develop disseminated CMV infection, which may cause chorioretinitis (resulting in blindness), colitis, or encephalitis.
Infected infants ages 3 to 6 months usually appear asymptomatic but may develop hepatic dysfunction, hepatosplenomegaly, spider angiomas, pneumonitis, and lymphadenopathy.
Congenital CMV infection is seldom apparent at birth, although the infant’s urine contains CMV. About 1% of all newborns have CMV.
The virus can cause brain damage that may not show up for months after birth. Occasionally, it produces a rapidly fatal neonatal illness characterized by jaundice, petechial rash, hepatosplenomegaly, thrombocytopenia, hemolytic anemia, microcephaly, psychomotor retardation, mental deficiency, and hearing loss.

In some adults, CMV may cause cytomegalovirus mononucleosis, with 3 weeks or more of irregular, high fever.
Other findings may include a normal or elevated white blood cell (WBC) count, lymphocytosis, and increased atypical lymphocytes.
TopDiagnosis
Although virus isolation in urine is the most sensitive laboratory method, a diagnosis can also rest on virus isolation from saliva, throat, cervix, WBC, and biopsy specimens.
Other laboratory tests support the diagnosis, including complement fixation studies, hemagglutination inhibition antibody tests and, for congenital infections, indirect immunofluorescent tests for CMV immunoglobulin M antibody.

TopTreatment
Because CMV infection is usually self-limiting, treatment aims to relieve symptoms and prevent complications. In the immunosuppressed patient, however, CMV is treated with acyclovir, ganciclovir, and foscarnet, combined with anti-CMV immune globulin for pneumonitis and possible GI disease.

TopSpecial considerations
❑ Provide parents of children with severe congenital CMV infection with counseling to help them cope with the possibility of brain damage or death.
❑ To help prevent CMV infection, warn immunosuppressed patients and pregnant women to avoid exposure to confirmed or suspected CMV infection. Tell pregnant patients that maternal CMV infection can cause serious fetal abnormalities.
❑ Urge patients with CMV infection — especially young children — to wash their hands thoroughly to prevent spreading it.
❑ Observe standard precautions when handling body secretions.
Copyright Details: Handbook of Diseases, Copyright © 2003 Lippincott Williams & Wilkins.

Copyright notice for book excerpts: Copyright © 2007 Lippincott Williams & Wilkins. All rights reserved.


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More About This Book:
Title: Handbook of Diseases
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2003
ISBN: 1-58255-266-5




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