A Review of Sensorineural Hearing Loss in Congenital Cytomegalovirus Infection

The intrauterine transmission of the TORCH group (toxoplasmosis, rubella cytomegalovirus (CMV), herpes simplex, and HIV) produces severe complications in the fetus, leading to major life challenges for the newborns. CMV is considered one of the leading causes of congenital hearing loss in babies born to infected mothers. The majority of the cases are asymptomatic but a certain proportion show symptoms, which may not be present until later. The human cytomegalovirus (HCMV) infection can also be transferred to the baby postnatally through breastfeeding. Mothers facing primary infection from the CMV have a greater tendency to transmit the infection to the fetus, whereas secondary infection due to reactivation of the virus in females who were affected before pregnancy, delivers asymptomatic babies in most cases. Vertical transmission of HCMV, that is via the placenta from infected mother to fetus, is one of the leading causes of congenital sensorineural hearing loss (SNHL) and neurodevelopmental complications in newborns. It accounts for up to 10% of SNHL cases in newborns, of both unilateral and bilateral types. Antiviral therapy is helpful in such cases if administered within the first month of life, and for hearing impairment, cochlear implants have been used to treat children who develop profound hearing loss. The child can present with hearing loss at birth or it may be late in onset and of progressive type. Suspected children should be evaluated regularly for the early detection of hearing loss and to provide the appropriate treatment.