Vestibular and balance dysfunction in children with congenital CMV: a systematic review

"Minimally symptomatic" congenital cytomegalovirus infection: latest data and emerging concepts

PURPOSE OF REVIEW

Universal and targeted screening of newborns for congenital cytomegalovirus (CMV) infection is increasing globally. Questions remain concerning the management of infants who have been identified with congenital CMV infection, especially those with "minimally symptomatic" or clinically inapparent infection. Our objective is to discuss current management of CMV-infected neonates with a focus on less affected infants with or without sensorineural hearing loss (SNHL).

RECENT FINDINGS

Valganciclovir is being prescribed increasingly in neonates with congenital CMV infection for improvement in hearing outcomes through 2 years of age. Treatment initiated in the first month of age is recommended for clinically apparent disease. A recent study showed hearing improvement at 18-22 months of age when therapy was initiated at age 1-3 months in infants with clinically inapparent CMV infection and isolated SNHL.

SUMMARY

Antiviral therapy with either ganciclovir or valganciclovir has shown moderate benefit in prevention of hearing deterioration among infants with clinically apparent CMV infection or isolated SNHL. Sustainability of benefit beyond 2 years of age remains unknown. At present, infants with clinically inapparent CMV infection (normal complete evaluation including hearing) should not receive antiviral therapy. All CMV-infected infants require close audiological and neurodevelopmental follow-up.

[Neurodevelopment and neuroprotection in young children]

In France, the most pessimistic estimates put the prevalence of neurodevelopmental disorders (NDD) at 15 % of births. The two largest populations of newborns at highest risk of NDD are premature babies and babies born into siblings with one or more infants who already have an autism spectrum disorder or another NDD. The high prevalence of these disorders justifies a health promotion policy, centred on the child and his or her family. Prevention is based on the early identification of high-risk factors, by informing families and training pregnancy and early childhood professionals, and implementing perinatal prevention protocols for high-risk newborns (antenatal corticosteroid therapy and magnesium sulfate for women at risk of preterm delivery before 32 weeks, developmental care, therapeutic hypothermia for full-term infants with early neonatal encephalopathy presumed to be anoxic). Preventing the severity of NDD depends on their early identification, as early as possible in the highest plastic "1000 days" developmental window, a smooth flow of diagnosis and care for mothers and children, and the establishment of an ecosystem that includes multi-modal early intervention, at the best in multi-disciplinary teams such as the early medical and social action centres, support for families through guidance programs and inclusion in the community, first in day-care centers and then in nursery schools.

Cytomegalovirus and Pregnancy: A Narrative Review

Cytomegalovirus (CMV) infection is the most common congenital infection worldwide, affecting between 0.7% and 1% of all live births. Approximately 11% of infected newborns are symptomatic at birth, and between 30% and 40% of these are at risk of developing long-term neurological sequelae. Until recently, the lack of an effective treatment did not justify universal testing of pregnant women. In recent years, however, valacyclovir at a dose of 8 g/day has been shown to be effective in preventing vertical transmission, and ganciclovir has been shown to be effective in preventing long-term sequelae in the treatment of symptomatic neonates. The aim of this article is to review congenital CMV infection, from its epidemiology to its treatment, using the most recent studies in the literature, and to help in the decision to modify protocols for universal testing of pregnant women according to the possibilities of each locality.

Newborn cytomegalovirus screening: is this the new standard?

PURPOSE OF REVIEW

Congenital cytomegalovirus infection (cCMV) is a major cause of childhood hearing loss and neurodevelopmental delay. Early identification of cCMV allows for interventions that improve outcomes, particularly for cCMV-related hearing loss that develops in early childhood. Most cCMV is asymptomatic at birth and is rarely diagnosed without newborn screening. Therefore, various approaches to cCMV screening are increasingly being adopted.

RECENT FINDINGS

Both universal screening (testing all newborns) and targeted screening (testing triggered by failed hearing screening) for cCMV appear valuable, feasible and cost-effective, though universal screening is predicted to have greatest potential overall benefits. CMV PCR testing of newborn oral swabs is sensitive and practical and is therefore widely used in targeted screening programs. In contrast, PCR using dried-blood spots (DBS) is less sensitive but was adopted by current universal cCMV screening initiatives because DBS are already collected from all newborns in high-income countries, which circumvents large-scale oral swab collection.

SUMMARY

Targeted screening is widely recommended as standard of care, while universal screening is less common but is progressively considered as the optimal strategy for identification of children with cCMV. As with all screening programs, cCMV screening requires commitments to equitable and reliable testing, follow-up and services.

Congenital cytomegalovirus infection: the state of the art and future perspectives

Congenital cytomegalovirus (cCMV) infection is the most common congenital infection, with an estimated incidence of approximately one in 200 infants in high-income settings. Approximately one in four children may experience life-long consequences, including sensorineural hearing loss and neurodisability. Knowledge regarding prevention, diagnosis, and treatment increased in the recent years, but some challenges remain. In this review, we tried to summarize the current knowledge on both the obstetrical and pediatric areas, while also highlighting controversial aspects and future perspectives. There is a need to enhance awareness among the general population and pregnant women through specific information programs. Further research is needed to better define the classification of individuals at birth and to have a deeper understanding of the long-term outcomes for so defined children. Finally, the availability of valaciclovir medication throughout pregnancy, where appropriate, has prompted the assessment of a universal serological antenatal screening. It is recommended to establish a dedicated unit for better evaluation and management of both mothers and children.

Vestibular Follow-up Program for Congenital Cytomegalovirus Based on 6 Years of Longitudinal Data Collection

OBJECTIVES

Congenital cytomegalovirus (cCMV), the leading nongenetic cause of pediatric sensorineural hearing loss, can also affect vestibular function. Literature findings suggest clinical presentation of vestibular loss in cCMV to be as variable as the hearing loss. Still, probably due to the considerable additional burden it entails for both patients and diagnostic centers, longitudinal vestibular follow-up in cCMV is not well-established in clinical practice. Therefore, this study aims to propose an evidence-based vestibular follow-up program with proper balance between its feasibility and sensitivity.

DESIGN

In this longitudinal cohort study, 185 cCMV-patients (mean age 3.2 years, SD 1.6 years, range 0.5-6.7 years) were included. Vestibular follow-up data were obtained through lateral video head impulse test (vHIT) and cervical vestibular evoked myogenic potential (cVEMP) evaluations around the ages of 6 months, 1 year, and 2 years. Around 3 and 4.5 years of age, data from vertical vHIT and ocular vestibular evoked myogenic potentials (oVEMP) were also collected.

RESULTS

At birth, 55.1% (102/185) of patients were asymptomatic and 44.9% (83/185) were symptomatic. The mean duration of follow-up for all patients was 20.8 (SD 16.3) months (mean number of follow-up assessments: 3.2, SD 1.5). Vestibular loss occurred at some point during follow-up in 16.8% (31/185) of all patients. Six percent (10/164) of patients with normal vestibular function at first assessment developed delayed-onset vestibular loss; 80.0% (8/10) of these within the first 2 years of life. Vestibular deterioration was reported both in patients who had been treated with postnatal antiviral therapy and untreated patients. At final evaluation, both the semicircular and the otolith system were impaired in the majority of vestibular-impaired ears (29/36, 80.6%). Dysfunctions limited to the semicircular system or the otolith system were reported in 4 (4/36, 11.1%) and 3 (3/36, 8.3%) ears, respectively. The occurrence of vestibular loss was highest in patients with first trimester seroconversion (16/59, 27.1%) or with an unknown timing of seroconversion (13/71, 18.3%), patients with sensorineural hearing loss (16/31, 51.6%), and patients with periventricular cysts on magnetic resonance imaging (MRI) (7/11, 63.6%).

CONCLUSIONS

Longitudinal vestibular follow-up, most intensively during the first 2 years of life, is recommended in cCMV-patients with vestibular risk factors (first trimester or unknown timing of seroconversion; sensorineural hearing loss; periventricular cysts on MRI). If those risk factors can be ruled out, a single evaluation early in life (around 6 months of age) might be sufficient. Both semicircular and otolith system evaluation should be part of the follow-up program, as partial losses were reported.

Congenital Cytomegalovirus and Hearing Loss: The State of the Art

In developed countries, congenital cytomegalovirus (cCMV) infection is the most common congenital viral infection, representing the leading non-genetic cause of sensorineural hearing loss (HL). Diagnosis of cCMV infection can be performed by detection of CMV DNA in urine or saliva within 2-3 weeks after birth, or later in dried blood samples on the Guthrie card. Currently, there are many controversies regarding the preventive, diagnostic, and therapeutic approaches to cCMV infection. HL secondary to cCMV is highly variable in onset, side, degree, audiometric configuration, and threshold changes over time. Therefore, it is of paramount importance to perform a long and thorough audiological follow-up in children with cCMV infection to ensure early identification and prompt treatment of progressive and/or late-onset HL. Early cochlear implantation appears to be a valid solution not only for children with bilateral profound HL, but also for those with single-sided deafness, improving localization ability and understanding speech in noisy environments. Moreover, the decision to apply a unilateral cochlear implant in children with cCMV is strengthened by the non-negligible possibility of hearing deterioration of the contralateral ear over time.

Long-term outcome of vestibular function and hearing in children with congenital cytomegalovirus infection: a prospective cohort study

PURPOSE

Congenital cytomegalovirus infection (cCMV) is the most frequent nonhereditary cause for sensorineural hearing loss (SNHL) in children. Data on vestibular function in children with cCMV are, however, scarce, although some evidence for cCMV-associated vestibular dysfunction exists. In this prospective cohort study, we evaluated long-term vestibular function and hearing outcomes in a cohort of children with cCMV.

METHODS

Participants were 6-7-year-old children with cCMV from a large population-based screening study. Controls were age and gender matched healthy children, who were CMV-negative at birth. Hearing was examined with pure tone audiometry. Definition of hearing loss was pure-tone average > 20 dB. Vestibular function was assessed using the video head impulse test that provides a measure of semicircular canal function. Definition of vestibular dysfunction was lateral semicircular canal gain < 0.75.

RESULTS

Vestibular dysfunction occurred in 7/36 (19.4%) of children with cCMV and in 1/31 (3.2%) of controls (p = 0.060). SNHL was recorded in 4/38 (10.5%) of children with cCMV and in 0/33 of controls (p = 0.118). Hearing loss was unilateral in all cases. In cCMV group, the two children with bilateral vestibular dysfunction also had SNHL, whereas those with unilateral vestibular dysfunction (n = 5) had normal hearing.

CONCLUSIONS

In this cohort of children with cCMV identified using newborn screening, vestibular dysfunction was more common than SNHL at 6 years of age. Vestibular dysfunction occurred both in children with and without SNHL. Based on these data, inclusion of vestibular tests in follow-up protocol of cCMV should be considered.

Hearing outcomes in children with congenital cytomegalovirus infection: From management controversies to lack of parents' knowledge

OBJECTIVES

Congenital cytomegalovirus (cCMV) is the leading nongenetic cause of sensorineural hearing loss (HL). However, there are no universally accepted approaches to diagnosis, follow-up and treatment. The aim of this study was to evaluate the main characteristics of cCMV-infected children, focusing on their management and long-term hearing outcomes.

METHODS

This retrospective study included all children with cCMV infection who were referred to a third-level referral audiologic center for a 6-year hearing follow-up. The main information collected from the medical records included gestational age, birth weight, trimester of maternal seroconversion, hearing status at birth and after 6 years, hearing fluctuations, treatment with oral valganciclovir (within the first month of life and for 6 months), use of hearing devices, presence of speech-language delay, motor delay, cognitive delay and balance disorders, awareness of cCMV among parents, and parents' engagement in behaviors that could increase the risk of CMV infection during pregnancy.

RESULTS

A total of 141 children with cCMV infection (72 males and 69 females; mean gestational age: 37⁺³ weeks; mean birth weight: 2893 g) were assessed. Overall, 48 children (34.0%) had a diagnosis of speech-language delay, 32 (22.7%) of sensorineural HL (59.4% bilaterally; 50% of profound degree), 18 (12.8%) of motor delay, 16 (11.3%) of balance disorders, and 6 (4.3%) of cognitive delay. Among children with HL, 8 (25.0%) were fitted with hearing aids (5 unilaterally and 3 bilaterally), and 5 (15.6%) had undergone cochlear implantation (1 unilaterally and 4 bilaterally), while a bimodal hearing solution was adopted for 2 (6.3%) patients. Compared to children with asymptomatic cCMV infection, symptomatic children had a higher prevalence of neurological and auditory sequelae (P < 0.01) and bilateral (P = 0.003) and severe-to-profound HL (P = 0.004). Overall, 23 children (16.3%) received oral valganciclovir, and only one of them experienced hearing deterioration. Only 14.9% of mothers and 5% of fathers were aware that cCMV could cause progressive or late-onset HL, and 87.9% of parents (248/282) had engaged in behaviors that increased the risk of CMV infection during pregnancy.

CONCLUSION

This study confirmed the importance of performing a long audiological follow-up in children diagnosed with cCMV infection due to the possible late-onset, progressive and fluctuating nature of HL. Moreover, the study highlighted many current controversies in preventive (poor prenatal education), diagnostic (routine maternal serological screening) and therapeutic (valganciclovir administered to asymptomatic children) approaches to cCMV infection. More efforts should be made to improve prevention strategies and raise awareness of cCMV infection risks among the population.