What is the pathophysiology of congenital cytomegalovirus (CMV) infection?

Updated: Jul 07, 2021
  • Author: Ricardo Cedeno-Mendoza, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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CMV is the leading cause of congenital infection worldwide (0.2-6.1% of live births), as well as the most common congenital viral infection the United States (20000 to 30000 infants/year, mostly black infants) and the leading cause of sensorineural hearing loss and neurodevelopmental delay in children. Congenital CMV-related sequelae affect over 5000 children per year, and add significant cost in direct medical care in the United States. The transplacental transmission rate after maternal primary infection is around 32%. The risk for transmission is low following maternal infection occurring more than 11 weeks before conception. [15, 16, 17, 18]

Most infants are asymptomatic, however, symptomatic infants are seen in about 10% of the patients with a broad range of disease manifestations. These include thrombocytopenia, petechiae, hepatomegaly, splenomegaly, hepatitis, intrauterine growth restriction, CNS involvement (microcephaly, ventriculomegaly, intracerebral calcifications, white matter changes with seizures and abnormal tone), ophthalmologic abnormalities (chorioretinitis, optic atrophy), and sensorineural hearing loss, among others. Mortality due to congenital CMV infection is low (approximately 4% of infants). Symptomatic disease can be classified as moderate to severe (multiple manifestations with or without CNS involvement) or mild disease (1-2 manifestations with no CNS involvement). [15, 18]

In pediatric population, congenital CMV infection is the most common cause of non-genetic sensorineural hearing loss (SNHL), this is also the most common permanent sequelae of congenital CMV infection. Other complications include cognitive impairment, chorioretinitis and cerebral palsy. Other manifestations include motor deficits and seizures as well in 23% and 19% respectively. CMV screening approaches could lead to identification of many more infants with congenital CMV infection than are currently identified because of clinical signs. Trials are ongoing to formulate a vaccination for pregnant woman. [15, 19, 20]

Increased rates of reactivation and cervical shedding are seen in advanced stages of gestation and congenital infection is associated with sequelae previously described. Prevention includes hand hygiene to minimize occupationally acquired CMV (such as daycare centers), as well as limiting the number of sexual partners (during pregnancy). [21]

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