The influence of locally implanted high doses of gentamicin on hearing and renal function of newborns treated for acute hematogenous osteomyelitis

Abstract

BACKGROUND: [corrected] Osteomyelitis and arthritis still present a serious diagnostic and therapeutic problem. Difficulties arise in particular in the treatment of acute hematogenic osteomyelitis (AHO) in newborns where mega-doses of gentamicin are administered locally for about 3 weeks. Gentamicin possesses strong oto- and nephrotoxicity and the occurrence of these adverse effects depends on the duration of treatment and the serum drug concentration. OBJECTIVE: Aim of the study was to evaluate the influence of local gentamicin application on auditory and kidney functions. MATERIAL AND METHODS: Twenty newborns (14 boys and 6 girls) with AHO were treated at the Department of Pediatric Surgery, Marciniak Hospital, Wroclaw, Poland, by local implantation of miniseptopal or gentamicin sponge. Serum urea, creatinine, antibiotic concentrations and NAG activity/g creatinine ratio in urine were estimated before and 1, 4, 8, 16 days after the operation and compared to values in the control group. Brainstem-evoked auditory potentials (BAEP) were examined before, during the first 3 weeks, and 6-11 months after gentamicin implantation. RESULTS: Mean gentamicin serum concentrations were: 0.67 +/- 0.98 mg/l on the 1st day, 0.16 +/- 0.37 mg/l on the 4th day, 0.03 +/- 0.09 mg/l on the 8th day, 0.01 +/- 0.03 mg/l on the 16th day after operation and did not exceed the upper limit of the therapeutic range. N-acetyl-beta-D-glucosaminidase (NAG)/g creatinine in urine ratios were satisfactory: 77.91 +/- 36.22 UI/g before the operation, 146.51 +/- 82.27 UI/g on the 4th, 162 +/- 111 UI/g on the 8th, 168 +/- 59.83 UI/g on the 16th day after operation and were statistically significantly (p < 0.05) higher than values in the control group. Serum urea and creatinine levels were in the normal range in all groups. Initial BAEP were well in the normal range in 15 of 16 children before treatment and in 14 of 16 children after treatment. CONCLUSIONS: Locally applied gentamicin as miniseptopal or sponge in newborns produces gentamicin concentrations close to the minimal therapeutic serum concentration which are present over a prolonged period. The raised NAG values in urine and normal serum urea and creatinine levels during treatment with gentamicin without concomitant clinical symptoms of renal failure suggest subclinical destruction of the renal tubules. Lack of change in BAEPs shows that there is no impairment of auditory function.