Of the over 4 million infants born each year in the USA, nearly 3.5 million are over 35 weeks of gestation and should have benign outcomes with little or no threat of neurological compromise during the first year after their birth. Most are discharged from their birth hospital before 72 h of age, prior to the usual peak of TB, which occurs between age 72 and 120 h. The jaundice usually resolves by 7-10 days of age and the outcome is benign. However, significant hyperbilirubinemia (>95th percentile for age in h) occurs in 8-11% of infants, with approximately 2-5% requiring readmission to a hospital for treatment. The exact incidence of chronic bilirubin encephalopathy is not known or surveyed, however, it should be exceedingly rare in current clinical practice. In one study, 125 cases were documented in the voluntarily reported Pilot USA Kernicterus Registry for term and late preterm infants (1992-2004). Approximately one in 650 to 1000 infants greater than 35 weeks of gestation can develop serum bilirubin values greater than 25 mg per 100 ml (>427 μmol/l) and approximately one in 10,000 have levels greater than 30 mg per 100 ml (>513 μmol/l). The frequency of catastrophic hyperbilirubinemia (TB > 513 μmol/l) is listed in Table 1. There is a varying occurrence of infants with TB levels greater than 25 mg per 100 ml and incidence of chronic kernicterus from diverse communities and practices. In Denmark, there were no case reports of kernicterus in the 20 years prior to a report of eight cases between 1994 and 2002 (incidence of 1.4/100,000 live births). Between 2002 and 2005, with a more vigilant approach to newborn jaundice management, the overall incidence was reduced to 1.1/100,000 live births between 1994 and 2005.[23,24] The estimated risk of kernicterus in infants with TB greater than 25 mg per 100 ml ranges from one in 14 to one in 16. This compares to a risk range of one in four to one in seven in infants with TB greater than 30 mg per 100 ml. None of the retrospective data provide any insight to signs of acute kernicterus in infants with TB greater than 25 mg per 100 ml.
Pediatr Health. 2009;3(4):369-379. © 2009 Future Medicine Ltd.
Cite this: Screening for Severe Neonatal Hyperbilirubinemia - Medscape - Aug 01, 2009.