Hyperbilirubinemia
HyperbilirubinemiaMonica StemmleObjectivesUnderstand pathway where bilirubin comes fromPhysiologic vs Pathologic HyperbilirubinemiaUnderstand the risk for Kernicterus Understand why we care about hyperbilirubinemiaPhysiology
Bilirubin = breakdown of hemoglobinConjugation is carried out by UGT (uridine diphosphate glucoronosyl transferase)Once in the gut in babies they have an enzyme called beta glucuronidase that de conjugates the bilirubin 3Physiologic hyperbilirubinemia1. Increased production: Increased RBC volume and decreased lifespan of RBC in neonates 2. Decreased Excretion: UGT activity is decreased in neonates for first few days. Also increased enterohepatic circulation
Pathologic HyperbilirubinemiaCan you name some of the risk factors :1. Increased bilirubin load?2. Decreased bilirubin clearance?Increased bilirubin loadHemolysisImmune mediated (ABO, rH, minor antigens)Heritable defects (RBC membrane defect, RBC enzyme defects, hemoglobinopathies)Sepsis/DICHematomasPolycthemiaMacrosomiaIncreased enterohepatic ciculation6Decreased bilirubin clearanceG6PD deficiencyMeconium plugImperforate anus7Risk of HyperbilirubinemiaKERNICTERUSKernicterusPhysiology not well understoodBelieved that exposure to bilirubin at a sensitive window of neuronal development may lead to apoptosisRequires PROLONGED HIGH bilirubin
9Kerniticus studies1. Outcomes among Newborns with Total Serum Bilirubin Levels of 25 mg per Deciliter or More Thomas B. Newman N Engl J Med 354;18 may 4, 2006Kaiser data. Infants with bili >24. No cases of kernicterus and no neurologic difference2. Outcomes in a Population of Healthy Term and Near-Term Infants With Serum Bilirubin Levels of >19 mg/dL Who Were Born in Nova Scotia, Canada, Between 1994 and 2000. Pediatrics. Jangaard et al. 122 (1): 119. (2008).Babies in Nova Scotia bw 1994-2000. No dif in neuro problems or deafness between severe hyperbili (>19) and no hyperbili (
