Cytomegalovirus

Cytomegalovirus (CMV) is a large DNA virus of the Herpes virus group. It is estimated that 50% to 80% of adults have prior evidence of CMV infection (58). The infection is usually subclinical when contracted by immunocompetent infants and adults and infrequently may lead to a mononucleosis-type syndrome. However, significant sequelae exist from in-utero infections as well as infections in immunocompromised patients.

Neurologic involvement almost always is associated with immunosuppression or in-utero infections. Neurologic sequelae include encephalitis, myelitis, polyneuritis, and cranial nerve involvement (59). Facial nerve involvement has been implicated in CMV infections, but the true incidence of facial nerve involvement is difficult to quantify, given the ubiquitous nature of the virus and its relatively asymptomatic state in immunocompe-tent patients. However, one study documented significant levels of CMV-specific antibodies of IgM and/or IgG in 64 of 88 patients (73%) presenting with idiopathic acute peripheral facial palsy (60). Importantly, though, CMV replication of the dormant virus and acute facial palsy may be only coincidental and not pathologically linked (60).

The pathogenesis of neurologic involvement is likely due to direct injury by the virus, which results in cell lysis after infection. The diagnosis is made by histopathologic identification of inclusion bodies and enlarged cells as well as elevated titers of antibodies to CMV. Treatment is with gangcyclovir, only used in immunosuppressed patients. Treatment for immunocompetent patients is symptomatic, but infectious patients should avoid exposure to pregnant women. The prognosis for facial recovery is good, with most reported cases recovering full function within weeks to months (58).

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