Congenital cytomegalovirus (cCMV) infection is the most common fetal viral infection and contributes to about 25% of childhood hearing loss by the age of 4 years. It is the leading nongenetic cause of sensorineural hearing loss (SNHL). Infants born to seroimmune mothers are not completely protected from SNHL, although the severity of their hearing loss may be milder than that seen in those whose mothers had a primary infection. Both direct cytopathic effects and localized inflammatory responses contribute to the pathogenesis of cytomegalovirus (CMV)-induced hearing loss. Hearing loss may be delayed onset, progressive or fluctuating in nature, and therefore, a significant proportion will be missed by universal newborn hearing screening (NHS) and warrants close monitoring of hearing function at least until 5-6 years of age. A multidisciplinary approach is required for the management of hearing loss. These children may need assistive hearing devices or cochlear implantation depending on the severity of their hearing loss. In addition, early intervention services such as speech or occupational therapy could help better communication, language, and social skill outcomes. Preventive measures to decrease intrauterine CMV transmission that have been evaluated include personal protective measures, passive immunoprophylaxis and valacyclovir treatment during pregnancy in mothers with primary CMV infection. Several vaccine candidates are currently in testing and one candidate vaccine in phase 3 trials. Until a CMV vaccine becomes available, behavioral and educational interventions may be the most effective strategy to prevent maternal CMV infection.
Keywords: ABR thresholds; Auditory brainstem response and otoacoustic emissions; Aural preference syndrome; Behavioral audiometry; Betaherpesvirus; Blood-labyrinth barrier; CMV PCR; CMV-specific hyperimmune globulin; Cerebellar hypoplasia; Cerebral atrophy; Cochlear blood–labyrinth barrier; Cochlear implant; Cytomegalic inclusion disease; Cytomegalovirus (CMV); Dried blood spot (DBS); Endocochlear potential; Fluctuating hearing loss; Ganciclovir; Herpesviridae; Human Herpes Virus 5; Icosahedral capsid; Impedance audiometry; Intracranial calcifications; Lenticulostriate vasculopathy; MF59-adjuvanted CMV glycoprotein B subunit vaccine; Migrational abnormalities; Natural killer; Neurotrophins; Newborn hearing screening; Nlrp3; Non-primary maternal infection; Organ of corti; Periventricular echo density; Play audiometry; Pure tone audiometry; Sensorineural hearing loss (SNHL); Seroimmune; Speech audiometry; Spiral ganglion cells; Spiral ganglion neurons; Strain-specific epitopes; Stria vascularis; Tegument layer; Tympanometry; Unique long gene region; Unique short gene region; Valganciclovir; Ventricular adhesions; Ventricular dilatation; Ventriculomegaly; Viral core; Viral lipid bilayer envelope; Viral matrix; Viral replication cycle; Visual reinforcement audiometry; White matter disease.