Cytomegalovirus infection
Cytomegalovirus (CMV) infection is caused by the cytomegalovirus, a deoxyribonucleic acid, ether-sensitive virus belonging to the herpes family. Also known as generalized salivary gland disease or cytomegalic inclusion disease, CMV infection occurs worldwide and is transmitted by human contact.
Causes
CMV has been found in the saliva, urine, semen, breast milk, feces, blood, and vaginal and cervical secretions of infected people. The virus is usually transmitted through contact with these infected secretions, which can harbor the virus for months or even years. It may be transmitted by sexual contact and can travel across the placenta, 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.
About four out of five people 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. However, 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. About 1% of all neonates have CMV.
Signs 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. However, immunodeficient patients and those receiving immunosuppressants may develop pneumonia or other secondary infections. In patients with acquired immunodeficiency syndrome, disseminated CMV infection may cause chorioretinitis (resulting in blindness), colitis, encephalitis, abdominal pain, diarrhea, or weight loss. 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 neonate’s urine contains the virus. CMV can cause brain damage that may not show up for months after birth. It also can produce a rapidly fatal neonatal illness characterized by jaundice, petechial rash, hepatosplenomegaly, thrombocytopenia, hemolytic anemia, microcephaly, psychomotor retardation, mental deficiency, and hearing loss. Occasionally, this form is rapidly fatal.
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.
Diagnosis
CONFIRMING DIAGNOSIS Although virus isolation in urine is the most sensitive laboratory method, diagnosis can also be made with virus isolated from saliva, throat, cervix, WBCs, or biopsy specimens.
Other laboratory tests supporting the diagnosis include complement fixation studies, hemagglutination inhibition antibody tests and, for congenital infections, indirect immunofluorescent tests for CMV immunoglobulin M antibody.
Treatment
Treatment aims to relieve symptoms and prevent complications. In the immunosuppressed patient, CMV may be treated with acyclovir, ganciclovir, valganciclovir, cidofovir and, possibly, foscarnet. Most important, parents of children with severe congenital CMV infection need support and counseling to help them cope with the possibility of brain damage or death.
Special considerations
To help prevent CMV infection:
❑Because many patients who excrete CMV are asymptomatic, standard precautions should be maintained at all times.
❑Warn immunosuppressed patients and pregnant women to avoid exposure to confirmed or suspected CMV infection. (Maternal CMV infection can cause fetal abnormalities: hydrocephaly, microphthalmia, seizures, encephalitis, hepatosplenomegaly, hematologic changes, microcephaly, and blindness.)
❑Urge patients with CMV infection to use good hand hygiene to prevent spreading it. Stress this particularly with young children.
❑Be sure to observe standard precautions when handling body secretions.
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
Other Book Chapters Related to Infection
Read excerpts from these other book chapters related to Infection:
Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2008 Williams & Wilkins.
More About Causes of Infection
» Next page: Ebola virus infection (Professional Guide to Diseases (Eighth Edition))
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