06 Jan Cerebral Palsy Rare In Infants With Elevated Bilirubin Levels

MedicalResearch.com Interview with:
Yvonne Wu MD
Professor of Clinical Neurology and Pediatrics
UCSF School of Medicine

Medical Research: What is the background for this study? What are the main findings?
Dr. Wu: Newborn infants commonly have elevated bilirubin levels, manifested as jaundice, because the body’s mechanisms for breaking down bilirubin have not yet fully matured.  Although high bilirubin levels are almost always well tolerated, extremely high bilirubin levels may lead to brain injury, or kernicterus, which in turn can cause a very severe form of cerebral palsy.  When bilirubin levels are extremely high, or when bilirubin levels remain high despite phototherapy, it is recommended that an exchange transfusion be performed to prevent brain injury and cerebral palsy.  The American Academy of Pediatrics (AAP) has published recommendations on when an exchange transfusion should be performed, based on bilirubin level, age of infant and other clinical factors.  However, no previous study had examined the actual risk of cerebral palsy in infants whose bilirubin levels exceeded the exchange transfusion thresholds.

Among 500,000 newborns born at Kaiser Permanente Northern California over a 17-year period, we found 1833 who had at least one bilirubin level above the AAP exchange transfusion level.  There were only 3 cases of cerebral palsy due to kernicterus in this group, even though only 42 (2.3%) of them had received exchange transfusions.  All 3 infants had bilirubin levels at least 5 mg/dL above the AAP exchange transfusion threshold and all 3 infants had 2 or more other risk factors for brain damage, including prematurity, sepsis, hypoxia and the hereditary blood disorder G6PD deficiency.  We did not identify any cases of kernicterus among otherwise well term babies, even at bilirubin levels that exceeded the AAP exchange transfusion threshold.

Medical Research: What should clinicians and patients take away from your report?

Dr. Wu: The current AAP guidelines for exchange transfusions state that an initial trial of phototherapy is warranted for most newborns with bilirubin levels above exchange levels.  Our findings suggest the range of bilirubin levels at which phototherapy might be used rather than exchange transfusion may be higher than previously thought, especially in otherwise well term infants.  Cerebral palsy due to high bilirubin levels was rare in this modern cohort, and did not occur in a single infant with hyperbilirubinemia who was otherwise healthy with no risk factors for brain injury, regardless of severity of elevated bilirubin.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Wu: An exchange transfusion is an invasive procedure that entails risks to the baby, such as blood clot formation, blood pressure instability, bleeding, and changes in blood chemistry.  Our study raises the question whether the threshold for exchange transfusion could be higher for infants with high bilirubin levels who are otherwise healthy and who have no other risk factors for brain injury.  Additional large, population-based studies and models of risks, costs, and potential benefits of treatment would be helpful for the AAP committee currently updating guidelines for the management of high bilirubin and jaundice in newborn infant

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Last Updated on January 6, 2015 by Marie Benz MD FAAD