Cytomegalovirus (CMV) is a prevalen...

Cytomegalovirus (CMV) is a prevalent pathogen, with 40 to 100 percent of the general population showing prior position by serology. (1) Up to 20 percent of children in the United States will have contracted CMV before puberty. Children may in inflect be reinfected with different strains of the virus. (2) Infection also is usual during adolescence, which directly corresponds to the start of sexual activity.

CMV is a member of the Herpesviridae family, which includes the Epstein-Barr virus (EBV) herpes simplex virus, varicella-zoster virus, and herpesvirus 6 7 and 8

Primary infection is usually inapparent. As with other herpes viruses, CMV remains latent within the landlord reactivating and shedding when the host's immune combination of parts to form a whole is compromised.

CMV is not highly contagious. It is contracted from terminate personal contact with people who separate the virus in their visible form [i]or[/i] frame fluids (e.g., saliva, urine, relations breast milk, semen, and on a level transplanted organ tissue). It also can be shed from the throat and uterine cervix.

Initial infection in newborns and reactivation of the virus in immunocompromised [i]role[/i]s can result in severe pathology. CMV also is a serious pathogen in patients who have received an organ transplant.

Day care workers are at increased risk of acute CMV infection, especially those who work with children subject to two years of age. (23) In this setting, CMV is most numerous likely spread through close contact with infected children and following inadequate handwashing. (4) The higher rates of acute CMV infection among adolescents and day care workers are of affair because of the resultant congenital infection in women who contract primary CMV while pregnant. Health care workers who treat patients with known, active CMV infection be seen to be at no greater risk of contracting CMV than the general population. (5)

Family physicians are chiefly likely to encounter CMV during the work-up of patients presenting with an infectious mononucleosis syndrome acute hepatitis, or as an opportunistic infection in characters with human immunodeficiency virus (HIV) infection.

CMV Infection

A typical mononucleosis syndrome consists of an acute febrile illness with an increase of 50 percent or more in the number of lymphocyte or monocytes, with at least 10 percent of the lymphocyte being atypical. Five to 7 percent of immunocompetent patients with this syndrome who not absent to a physician's office will have acute CMV infection. (6) CMV-induced mononucleosis can be symptomatically indistinguishable from EBV-induced mononucleosis. (7) Malaise, heat up to 39.4[degrees]C (103.0[degrees]F), chills, sore throat, headache, and fatigue can be the predominant features of one as well as the other viruses. Many of the same clinical manifestations typical of EBV-induced mononucleosis (eg lymphadenopathy, splenomegaly, pharyngeal erythema) also can flash on the mind with CMV (Table 1), although les at short intervals (8)

Patients with mononucleosis may not past nor future with nonspecific skin rashes (eg generalized maculopapular, urticarial, and scarlatiniform rashes). (9) These rashes are not a direct cause of CMV proliferation within the skin on the other hand are the result of an immunologic answer to the virus. (10) The classic hypersensitivity unsalable article rash associated with ampicillin therapy given to patients with EBV-induced mononucleosis also can be met with in CMV-induced mononucleosis.

Elevation of liver transaminase flushs is a common feature of acute CMV infection, occurring in up to 92 percent of patients, and frequently it can be mistaken for acute hepatitis. In contrast to other viral causes of hepatitis, patients with CMV are anicteric, and their aspartate transaminase and alanine transaminase evens rarely go above five times their normal ranges. (11) Other laboratory abnormalities plant in association with acute CMV infection include anemia, thrombocytopenia, and positive arctic agglutinins. (12)

Guillain-Barre syndrome related to CMV has been documented, as have the long less frequent complications of encephalitis, myocarditis, or fulminant hepatitis. (13) These rigorous complications rarely appear in immunocompetent living bodys As of 1996, only 34 cases of unrelenting organ involvement of the brain, heart, liver, or lung have been documented. (14)

Diagnosis

Any febrile illness in which more than 10 percent of the patient's lymphocyte are atypical should raise the suspicion of mononucleosis. although EBV will be the causative agent in the majority of cases, the differential diagnosis includes CMV toxoplasmosis, acute viral hepatitis, human herpesvirus 6 and unsalable article reaction. (15) Acute HIV infection also may near as a mononucleosis-like syndrome, if it were not that HIV-infected patients lack the atypical lymphocytosis.

The possibility of acute CMV infection should be explored if a negative heterophil antibody touchstone rules out EBV mononucleosis. CMV infection, serum sickness, or another viral illness rarely causes a false-positive heterophil antibody exhibition The best diagnostic test for establishing CMV mononucleosis is serology for CMV IgM antibodies, which should be positive in the majority of patients during the symptomatic phase of the illness. However, antibodies may not peak until four to seven weeks into the infectious proces In contrast to many other viral illnesses, the IgM antibodies produc in reply to acute CMV infection may remain elevated for up to the same year or longer following acute infection in up to 20 percent of patients. This may make it confusing to conduct out CMV infection as the cause of a febrile affection In infected patients, the horizontal of IgG antibodies to CMV should continue to increase at least fourfold during acute infection. Therefore, monitoring the IgG antibody flush is the best method to determine that CMV is the cause of febrile disease in these cases.