Clinical assessment of bilirubin-induced neurotoxicity in premature infants.

The clinical assessment of bilirubin-induced neurotoxicity in premature infants remains difficult in the absence of a gestational age-specific total or free (unbound) bilirubin level that predicts bilirubin-induced neurotoxicity. Because the total serum bilirubin concentration is an unreliable predictor of bilirubin-induced neurotoxicity in premature infants, alternative mean for predicting bilirubin-induced neurotoxicity in jaundiced preterm newborns is needed. Over the last few years, we have witnessed substantial gain in our knowledge involving usefulness of bilirubin-binding variables (total bilirubin, free bilirubin, bilirubin:albumin molar ratio) for clinical assessment of bilirubin-induced neurotoxicity in preterm infants. The knowledge gained has provided impetus for more clinical studies that are geared toward confirming the usefulness of free bilirubin as a predictor of bilirubin-induced neurotoxicity and identifying the gestational age-specific free bilirubin level that may increase the risk of bilirubin-induced neurotoxicity in premature infants. The paper has attempted to provide an overview of bilirubin-induced auditory toxicity along with the existing clinical evidence in favor of free bilirubin assay and usefulness of auditory brainstem evoked response for evaluation of bilirubin-induced neurotoxicity in premature infants. In addition, the author has described findings that suggest an association of apnea, a clinical manifestation, with acute bilirubin encephalopathy in premature infants.