7 Predicting Kernicterus in Severe Unconjugated Hyperbilirubinemia

Kernicterus, a preventable brain injury due to severe unconjugated hyperbilirubinemia, has re-emerged worldwide. Survivors have hearing, speech and movement disorders as a long term outcome. Assessments after exchange transfusion may identify newborns that need early intervention, family support and appropriate follow-up.

To identify prognostic predictors of kernicterus in the newborn with severe unconjugated hyperbilirubinemia.

Retrospective cohort study with follow-up to a mean age of 17 months (range 6–36 months) of newborns >35 weeks gestation at birth, admitted between 1999-March 2003 to a regional tertiary care center for severe unconjugated hyperbilirubinemia (bilirubin >75%tile for age in hours). Abstracted data included clinical presentation, peak unconjugated bilirubin levels, neuroimaging findings, medical/interventional management, and long term follow-up. Predictors of kernicterus were identified by univariate and multivariate analyses.

29 newborns were admitted with severe unconjugated hyper-bilirubinemia. Peak bilirubin level ranged from 286 μmol/L at 6 hours to 780 μmol/L at 120 hours of age. All infants required an exchange transfusion. Auditory evoked responses (AER) were obtained on all newborns and 11/29 had neuroimaging in the acute phase. One died and 7 (27%) had findings suggestive of kernicterus (abnormalities of tone, hearing loss and developmental delay) at follow-up. Birth weight, gestational age, peak MBR, age at presentation, and age at intervention were not predictive of kernicterus.

Auditory evoked responses at 5–8 months of age were highly predictive of the later development of kernicterus. The usefulness of neuroimaging in the acute phase remains unclear. Hearing assessments should always be included in the follow up of newborns with severe unconjugated hyperbilirubinemia.