Hemolytic conditions in preterm neonates, including Rhesus (Rh) disease, can lead to mortality and long-term impairments due to
bilirubin neurotoxicity. Universal access to Rh immunoprophylaxis, coordinated perinatal-neonatal care, and effective
phototherapy has virtually eliminated the risk of
kernicterus in many countries. In the absence of
jaundice due to isoimmunization and without access to
phototherapy or exchange transfusion (in 1955),
kernicterus was reported at 10.1%, 5.5%, and 1.2% in babies <30, 31-32, and 33-34 wks gestational age, respectively.
Phototherapy initiated at 24±12 hr effectively prevented
hyperbilirubinemia in infants <2,000 g even in the presence of
hemolysis. This approach (in 1985) reduced exchange transfusions from 23.9% to 4.8%. Now with 3 decades of experience in implementing effective
phototherapy, the need for exchange transfusions has virtually been eliminated. However,
bilirubin neurotoxicity continues to be associated with prematurity alone. The ability to better predict this risk, other than
birthweight and gestation, has been elusive. Objective tests such as total
bilirubin, unbound or free
bilirubin,
albumin levels, and
albumin-
bilirubin binding, together with observations of concurrent
hemolysis,
sepsis, and rapid rate of
bilirubin rise have been considered, but their individual or combined predictive utility has yet to be refined. The disruptive effects of immaturity, concurrent
neonatal disease,
cholestasis, use of
total parenteral nutrition or drugs that alter
bilirubin-binding abilities augment the clinical risk of neurotoxicity. Current management options rely on the "fine-tuning" of each infant's exposure to beneficial
antioxidants and avoidance of silent neurotoxic properties of
bilirubin navigated within the safe spectrum of operational thresholds demarcated by experts.