Hearing Loss and Congenital Cytomegalovirus Infection
Hearing Loss and Congenital Cytomegalovirus Infection
Abstract & Commentary
By Hal B. Jenson, MD, FAAP, Professor of Pediatrics, Tufts University School of Medicine, and Chief Academic Officer, Baystate Medical Center, Springfield, MA, is Associate Editor for Infectious Disease Alert.
Synopsis: Congenital cytomegalovirus (CMV) infection affects 1% of newborns, even in populations with high levels of maternal seropositive status, with sensori-neural hearing loss in about 10% of these infants. Congenital CMV infection is the most common cause of sensorineural hearing loss in the United States.
Source: Mussi-Pinhata MM, et al. Birth prevalence and natural history of congenital cytomegalovirus infection in a highly seroimmune population. Clin Infect Dis. 2009;49:522-528.
A prospective study of congenital cytomegalovirus (CMV) infection was conducted in two hospitals in São Paulo, Brazil, from 2003 to 2007 in a maternal population with high seroprevalence to CMV. Saliva and/or urine samples were obtained from 8,047 consecutive newborns born to 7,848 mothers (192 twin pairs and seven sets of triplets) during the first two weeks of life and screened for CMV by PCR and virus culture. All specimens that were positive by PCR were also positive by virus culture.
All infants with confirmed infection had follow-up ophthalmologic evaluation, cranial-computed tomography, and hearing evaluation using auditory brainstem response during follow-up. Sensorineural hearing loss was defined as an air conduction threshold of > 30 decibels (dB).
Confirmed CMV infection occurred in 87 of 8,047 offspring (1.08%). Symptomatic neonatal infection was found in 0.09% of infants (seven of 8,047; 95% CI, 0.03%-0.18%). There were 63 of 87 (72%) CMV-infected children who underwent at least one auditory brainstem-response assessment, at a median age of 21 months (range, 3-63 months). Among these children, five (7.9%) had conductive hearing loss secondary to middle ear effusion and, therefore, cochlear function could not be assessed. Sensorineural hearing loss was found in five of the remaining 58 children (8.6%; 95% CI, 2.9%-19.0%). Three infants had bilateral hearing loss, including two with profound hearing loss (> 90 dB) and one with severe hearing loss (> 60 dB). Two infants had unilateral hearing loss, one with a threshold of 60 dB and one with a threshold of 90 dB. The remaining children had normal hearing.
Of the 44 mothers with CMV-infected offspring who had prenatal care specimens available, only two (4.5%) were seronegative and had a primary infection during gestation. The remaining 42 mothers (95.5%) were already seropositive for CMV. Of these mothers, 41 had high IgG avidity index (> 73%) and one (2.2%) had a low avidity index (13% at nine weeks of gestation). Considering that full maturation of IgG antibodies or high-avidity index occurs at 12-25 weeks after primary infection, presumed non-primary infection was responsible for 39 of 44 (88.6%) congenital infections.
Commentary
The finding of 1.1% prevalence of CMV infection is in alignment with other studies that have demonstrated a relatively significant rate of congenital infection in infants, even in a population with very high (95%) levels of maternal serologic immunity to CMV. Infants born to mothers with non-primary CMV infection have a significant risk of hearing loss of greater than moderate severity, as well as abnormal CT findings with neurodevelopmental delay.
Congenital CMV disease extends beyond symptoms in the newborn period, and accounts for approximately one-third of sensorineural hearing loss in children in the United States. In fact, most infants (90%) with congenital CMV infection are asymptomatic in the neonatal period, with the neurodevelopmental sequelae appearing in the first two years of life. The most significant abnormality in children with subclinical congenital CMV infection is sensorineural hearing loss, which may be bilateral in approximately 50% of cases.
Current recommendations call for all infants to have a hearing screening before one month of age, as well as for children through 36 months of age with one or more high-risk indicators on speech-language screening. An optimal screening strategy to identify all children with CMV-associated sensorineural hearing loss might require universal newborn hearing testing combined with virologic testing (e.g., PCR or culture). The ultimate preventive method is the development of a CMV vaccine that is effective in preventing congenital infection and the associated hearing loss.
A prospective study of congenital cytomegalovirus (CMV) infection was conducted in two hospitals in São Paulo, Brazil, from 2003 to 2007 in a maternal population with high seroprevalence to CMV.Subscribe Now for Access
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