Congenital Cytomegalovirus Infection as a Cause of Sensorineural Hearing Loss in a Highly Immune Population

Aparecida Y. Yamamoto, MD; Marisa Marcia Mussi-Pinhata, MD; Myriam de Lima Isaac, MD; Fabiana R. Amaral, MD; Cristina G. Carvalheiro, MD; Davi C. Aragon, MSc; Alessandra K. da Silva Manfredi, MSc; Suresh B. Boppana, MD; William J. Britt, MD.

Disclosures

Pediatr Infect Dis J. 2011;30(12):1043-1046. 

In This Article

Results

Among 121 infants with congenital CMV infection, 12 (10%) had clinical findings at birth that were consistent with symptomatic congenital infection, 5 had multisystem disease (1 died within the first week of life), and 4 showed at least one clinical finding. The remaining 3 infants had only cranial computerized tomography findings including abnormalities of neuronal migration, leading to polymicrogyria (1 infant), white matter gliosis and supratentorial ventriculomegaly (1 infant), and myelination delay in association with lissencephaly (1 infant). Of 12 symptomatic infants, 5 received 6 weeks of intravenous ganciclovir therapy (6 mg/kg/per day in 2 doses) and 4 of them had multisystem disease. None of the infected infants had abnormal findings on ophthalmologic examination. Intrauterine growth restriction was observed in 35 of 121 (28.9%) infants. Among 12 symptomatic infants, 8 (66.7%) were small for gestational age.

Hearing Outcome in Children With Congenital CMV Infection

The overview of the study population and the results of hearing evaluations are shown in Figure 1. Of the 121 infants, 102 (84%) with congenital CMV infection underwent at least one ABR assessment, and the median age of initial ABR testing was 12 months (range: 15 days–51 months; 18 of 102 [17.6%] <6 months, and 32 of 102 [30%] <12 months of age). Three infants had conductive hearing loss at the time of this analysis, and 14 infants (1 symptomatic) were lost to follow-up after undergoing only one ABR test. All of these 14 infants had normal hearing. Of the 102 children who underwent at least one ABR testing, 10 (9.8%; 95% confidence interval [CI]: 5.1–16.7) were demonstrated to have SNHL. Their median age at the latest hearing evaluation was 47 months (range: 12–84 months). Using more stringent criteria that included at least 2 ABR assessments and follow-up for at least 12 months, SNHL was confirmed in 10 of 85 (11.8%; 95% CI: 6.1–19.9) children; 6 of 11 with symptomatic (54.5%; 95% CI: 25.9%–81.3%), and 4 of 75 (5.3%; 95% CI: 1.7–12.4) with asymptomatic congenital CMV infection. Five children had bilateral hearing loss and among these, 4 (3 with multisystem disease and 1 asymptomatic in the neonatal period who had no abnormalities in the CT scan) had profound loss (>90 dB) and the remaining child with multisystem disease during neonatal period had moderate SNHL (60 dB). All 5 children with unilateral involvement (2 symptomatic and 3 asymptomatic) had moderate to severe SNHL (60–90 dB).

Figure 1.

Overview of the study population.

Of the 85 children, 65 (76%) whose hearing status could be ascertained completed follow-up for at least 36 months of age and underwent multiple hearing evaluations (median of 4 tests, range: 2–6). Their median age at the latest hearing evaluation was 56 months (range: 36–84 months). None of the 65 children had progression in the hearing deficit.

The demographic characteristics and newborn findings were compared among study children with at least 2 ABR evaluations according to their hearing status (Table 1). No association was observed between hearing loss and intrauterine growth restriction, gestational age, gender, maternal age, or gravidity. Although univariate analyses showed that children with abnormal findings at birth and those born to mothers younger than 20 years of age were more likely to develop hearing loss, only symptomatic congenital CMV infection remained independently associated with hearing loss. Additional risk factors for SNHL were observed in 1 infant who was born prematurely (32 weeks) and received intravenous aminoglycosides for more than 5 weeks after birth.

Newborn Hearing Screening Findings

Of 10 infants, 7 with confirmed hearing loss had been tested by OAE within the first month of life and 6 of these infants failed OAE. In all 6 children, ABR confirmed loss in the same ear in which OAE testing resulted in failure, suggesting that hearing loss was present at birth. In 1 child who had normal hearing at 2 months of age, ABR testing at 10 months of age revealed unilateral profound SNHL (109 dB). Among 75 infants with normal hearing, 30 had been screened by OAE in the neonatal period. Two of them had failed OAE in 1 ear, however, subsequent testing by OAE and at least 2 ABR assessments revealed normal hearing. Delayedonset SNHL could not be excluded in 3 children in whom hearing loss was detected at the time of their first ABR evaluations at older ages (21, 28, and 40 months) and did not undergo OAE testing during the neonatal period.

Maternal Immune Status and CMV-associated Hearing Loss

The data on association between the type of maternal CMV infection and hearing loss are shown in Table 2. Serum samples were collected from 43 (50%) of the mothers of 85 children, adequately evaluated by at least 2 ABR tests, during their first prenatal visit and at delivery. Seven infants of these 43 mothers had hearing loss and 6 of them were born to mothers with nonprimary maternal CMV infection as determined by the presence of CMV-IgG antibodies before pregnancy in 1 mother and by the presence of CMV-IgG antibodies of high avidity in serum samples obtained between 6 and 25 weeks of gestation in 5. The mother of the remaining infant with SNHL had primary infection as indicated by low-avidity CMV IgG antibodies in the serum sample obtained at 9 weeks of gestation.

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