[Effect of exchange transfusion on ABR abnormality due to severe neonatal hyperbilirubinemia]

ABSTRACT

Neonatal hyperbilirubinemia, as a very common problem in neonatal period, can lead to kernicterus which is a common cause of neuro-sensory hearing loss and an avoidable cause of deafness. The aim of this study was to detect toxic effect of severe hyperbilirubinemia on brain stem and auditory tract before and after exchange transfusion [ET] by Auditory Brainstem Responses [ABR]. ABR were measured in 12 full term newborns with severe hyperbilirubinemia [case] and 12 non-icteric full term neonates [control]. Total bilirubin concentration in jaundiced cases was >/=20mg/dl and direct bilirubin Birth weight, gestational age and age on admission were 3066 +/- 477gr, 39 +/- 1.4 weeks, and 4.25 +/- 3.1 days respectively. None of the newborns showed clinically symptoms and signs of bilirubin encephalopathy. Data are analyzed by SPSS software. Two neonates did-not show ABR waves before ET, these appeared after ET. The mean latencies time of wave V of ABR before, after and at 3 months of age was 7.53 +/- 0.34, 7.43 +/- 0.33, 6.99 +/- 0.29 milliseconds [P<0.001] respectively. This showed marked improvement. The mean inter-peak -Intervals [IPI] of waves III-V were 2.58 +/- 0.19, 2.65 +/- 0.19, 2.32 +/- 0.16 respectively [P<0.009] and the IPI of waves I-V were 5.38 +/- 0.29, 6.16 +/- 0.32, 4.84 +/- 0.28 [P<0.004] respectively. This means shortening of IPI after ET. Our results suggest that bilirubin neurotoxicity rapidly disappears after ET. Therefore, we recommend ABR for screening and early detection of bilirubin ototoxicity for necessary audiological intervention in all cases of severe neonatal hyperbilirubinemia