Hearing in Schoolchildren After Neonatal Exposure to a High-Dose Gentamicin Regimen

Ototoxic Drug Exposure and Hearing Loss in Neonates: A Scoping Review

PURPOSE

This scoping review aims to map the effects of dosage levels, dosage intervals, duration of exposure, and serum concentration levels of gentamicin, amikacin, vancomycin, furosemide, and bumetanide on newborn hearing.

METHOD

Using PubMed, Scopus, and Ovid databases (January 2010-2022), a scoping review was conducted to identify studies on ototoxic drug exposure in neonates. The review included articles that described details on ototoxic drug exposure and hearing status, dosage levels, duration of exposure, and serum concentration levels. The search results were summarized using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews.

RESULTS

Out of 4,395 entries, 28 were selected for inclusion in the scoping review. The studies were separated according to the exposed drugs: gentamicin, amikacin, vancomycin, furosemide, bumetanide, and a combination of drugs. Four out of five studies on amikacin exposure revealed an increased association with ototoxicity and abnormal trough levels. Six of seven studies on gentamicin exposure reported elevated trough concentration levels in a small number of infants, but no studies reported hearing loss. Two out of four studies on vancomycin exposure reported a dose-dependent risk for infants to develop hearing loss.

CONCLUSIONS

Gentamicin exposure in neonates has been extensively studied and considered relatively safe, except in cases of elevated peak or trough concentration levels. Amikacin exposure was reported to be more ototoxic, as the elevation of trough concentration levels was associated with refer results in hearing. Loop-diuretic exposure demonstrated a significant ototoxic effect. When used with other ototoxic medications, vancomycin is said to have a greater effect on ototoxicity.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26814700.

Extended high frequency audiometry thresholds in healthy school children

OBJECTIVES

Extended high frequency (EHF) audiometry is the recommended method for monitoring oxotoxic hearing loss in children. This study aims to provide high quality reference audiological data for the EHF range in healthy children.

METHODS

Participants were 126 healthy schoolchildren between 6 and 14 years of age. All participants were term born with normal birthweight, had not suffered severe neonatal illness and had no history of middle ear disease.

RESULTS

The averaged mean (SD) hearing threshold for the EHF 9, 10, 11.2, 12.5, 14 and 16 kHz was -0.4 (6.0) dB HL. The lowest mean hearing thresholds were observed at 14 kHz with -4.2 (8.7) dB and at 16 kHz with -6.4 (12.1) dB HL. We found significantly lower thresholds at 16 kHz for children aged 6-9 years (-8.7 dB HL) compared to age 10-14 years (-3.9 db HL), p 0.042. For both age groups the inter-subject variability increased in the highest frequencies. We found no significant differences in mean hearing thresholds between right and left ears at any frequency, and no gender differences in the EHF range.

CONCLUSION

Our findings support that decreased hearing sensitivity in the EHF's may start around or even before the age of 10 years. In order to use EHF audiometry for ototoxic monitoring in children, we suggest to establish an international reference standard for hearing levels in children under the age of 18. Specific references for different age groups are needed as hearing in the EHF range appears to gradually deteriorate from an early age.

CLINICAL TRIAL REGISTRATION

NCT03253614.

Exposure to an Extended-Interval, High-Dose Gentamicin Regimen in the Neonatal Period Is Not Associated With Long-Term Nephrotoxicity

Objectives: To assess the association between gentamicin exposure and subclinical signs of nephrotoxicity in school children who were exposed to a high-dose gentamicin regimen in the neonatal period. Methods: Children receiving three or more doses (6 mg/kg) of gentamicin as neonates were invited to a follow-up in school age. We evaluated potential signs of subclinical nephrotoxicity with four validated urine biomarkers: protein-creatinine ratio (PCR), albumin-creatinine ratio (ACR), kidney injury molecule-1 (KIM-1), and N-acetyl-beta-D-glucosaminidase (NAG) normalized for urine creatinine (NAG-Cr). In addition, blood pressure was measured. The measures of gentamicin exposure were cumulative dose (mg/kg) and highest trough plasma concentration (TPC) in mg/L. We used logistic and linear regression and non-parametric kernel regression to analyze the relationship between gentamicin exposure and the urine biomarkers. Results: A total of 222 gentamicin exposed children were included. As neonates, the children were exposed to a median (interquartile range-IQR) cumulative gentamicin dose of 36 (26-42) mg/kg and the median (IQR) TPC was 1.0 (0.7-1.3) mg/L. At follow-up, 15 children (6.8%) had either one abnormal urine biomarker value (13 children) or two abnormal urine biomarker values (2 children). These 17 biomarker values were all marginally above the suggested upper cutoff, and included the following markers; KIM-1 (n = 2), NAC-Cr (n = 5), ACR (n = 6), and PCR (n = 4). All other 207 children had normal sets of all four urine biomarkers. One child had hypertension. There were no differences in gentamicin exposure, gestational age (GA) at birth or birth weight between the group of 15 children with one or two abnormal urine biomarker values compared to the other 207 children who had normal biomarker values. Using different regression analyses, we did not find any association between gentamicin exposure (cumulative dose and/or TPC) and the urine biomarker values. Conclusions: Exposure to an extended-interval, high-dose gentamicin regimen in the neonatal period was not associated with signs of subclinical nephrotoxicity in schoolchildren. We therefore suggest that the gentamicin treatment regimen evaluated in this study is safe in terms of long-term nephrotoxicity. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT03253614.