Characteristics of neonatal Bilirubin metabolism Increased bilirubin production 8.8mg/kg daily vs 3.8mg/kg in adults Insufficiency of bilirubin transportation acidosis, hypoalbuminemia Immature of liver function lower ingestion(y, z protein); lower UDPGT activity Increased“ enterohepatic circulation” lower in gut bacteria; higher B-glucuronidase activity
Characteristics of Neonatal Bilirubin Metabolism ➢ Increased bilirubin production 8.8mg/kg daily vs 3.8mg/kg in adults ➢ Insufficiency of bilirubin transportation acidosis, hypoalbuminemia ➢ Immature of liver function lower ingestion (y, z protein); lower UDPGT activity ➢ Increased “enterohepatic circulation” lower in gut bacteria; higher b-glucuronidase activity
"Physiological Jaundice Seen in 60% of term infants and over 80% of preterm Serum values reaches maximum at 6mg/dl on 4.5d in term and 10-12 mg/dl on 5-7d in premature infants Jaundice declines gradually, reaching normal values within 2 wks in term, and 34w(1-2m)in preterm Causes no damage in term infants Up limit for abnormal? Undefined (Term <12mg/dl, or term<13, preterm<15mg/dI)
“Physiological” Jaundice ➢ Seen in 60% of term infants and over 80% of preterm ➢ Serum values reaches maximum at 6mg/dl on 4~5d in term and 10~12mg/dl on 5~7d in premature infants ➢ Jaundice declines gradually, reaching normal values within 2 wks in term, and 3~4w (1~2m) in preterm ➢ Causes no damage in term infants Up limit for abnormal? Undefined (Term <12mg/dl, or term<13, preterm<15mg/dl)
Factors likely to make “ physiological/ jaundice” worse prematurity bruising cephalohematoma polycythaemia delayed passage of meconium breast feeding certain ethnic groups, esp Chinese
Factors likely to make “physiological jaundice” worse ➢ prematurity ➢ bruising ➢ cephalohematoma ➢ polycythaemia ➢ delayed passage of meconium ➢ breast feeding ➢ certain ethnic groups, esp Chinese