A study of effect of aminoglycoside therapy on auditory brainstem evoked responses in preterm and term neonates

Background: Aminoglycosides are widely used drugs in neonates with associated ototoxic side effects, that can be diagnosed with auditory brainstem evoked responses, which is the recommended screening technique in neonatal intensive care unit infants.  This study was conducted to evaluate the effect of aminoglycoside therapy on auditory brainstem evoked responses in term and preterm neonates.Methods: A cross-sectional case control study. Two groups of 26 term and 22 preterm neonates who received aminoglycosides, with no other known risk factors for ototoxicity, were compared with suitable matched control group of 10 neonates in each. ABER was done after at least 5 days of aminoglycoside therapy and results were compared to suitable matched controls.Results: Mean latency of wave I in term neonates at 90 dB and 60 dB and mean interwave latencies of I-V waves in preterm neonates at 30 dB was higher in study group and statistically significant. No statistically significant difference in any of ABER parameters was observed in any group, at all other intensities.Conclusions: Wave I latency was prolonged in study group of term neonates at two intensities which indicates effect of aminoglycoside therapy on distal portion of acoustic nerve. But as there were no such findings at other intensities in term study group and in preterm study group and moreover no other ABER abnormalities were observed, it was concluded that the aminoglycoside therapy has low potential for ototoxicity. Authors support the ABER screening for early detection of hearing abnormalities, and recommend study on larger group of neonates and meta-analysis for final conclusion for evidence-based recommendations to use aminoglycosides in neonates, in view of audiometric and neurological abnormalities.

Normal parameters of ventricular system in healthy infants.

Six hundred healthy inborn newborns and infants upto the age of 18 months were studied. Cranial sonography was performed by real time 2D scanner with 5 MHz transducer and images were obtained through anterior fontanelle and temporo-squamal suture. Various parameters related to ventricular system were measured for different ages till the fontanelle remained open. These values will prove useful for diagnosing hydrocephalus at an early stage of the disease and also to find out the blocks at various levels in ventricular system.

Ultrasonic diagnosis of intracranial hemorrhage in high risk neonates.

One hundred and eleven high risk neonates were subjected to (cranial ultrasound (CR-USG) Caranial sonography was performed by 2D realtime scanner with 5 MHz transducer through anterior and posterior fontanelle and temporo-squamal suture. One quarter of these neonates developed intracranial hemorrhage (ICH) within 120 hours of birth. Of them 42.8% neonates recovered completely, 21.4% developed ventriculomegaly, 21.4% neonates expired, 10.4% developed pseudo-porencephalic cysts and 3.5% developed aqueductal block. It is concluded that CR-USG is a useful technique for detection and monitoring of complications of ICH and at least one screening sonogram is essential in the first week of life of all high risk neonates.

Cranial ultrasonic assessment of infants with acute bacterial meningitis.

A prospective study was performed on 44 patients (newborn to one year old) with acute bacterial meningitis. Sonograms were obtained within 72 hours of diagnosis, and repeated on 7th, 14th or at an early date, if required. The spectrum of sonographic features of meningitis included normal scan (35.4%), echogenic sulci (63.7%) and parenchyma (29.5%), ventriculomegaly (59%), ventriculitis (35%), pseudo-porencephalic cyst (4.4%), extra axial fluid collection (4.4%), encephalomalacia (2.2%) and cerebral abscess (2.2%) in patients.