The Metabolic Characteristics of Bilirubin in Newborns

1. The Metabolic Characteristics of Bilirubin in Newborns Wu jinlin Department of Pediatrics West China Second University Hospital Sichuan University

3. Baby on Phototherapy

4. Introduction of Neonatal Jaundice • Jaundice is quite common in neonatal period [1] 60% of term infants and 80% of preterm infants [2] Visible jaundice from sclera, mucosa and skin

5. respiratory failure bilirubin encephalopathy neonatal death Introduction of Neonatal Jaundice • Can cause serious consequences [1] Actue phase

6. cerebral palsy epilepsy mental retardation auditory and visual disfunctions [2] lifelong neurologic sequelae— kernicterus

8. The Metabolic Characteristics of Bilirubin in Newborns Why jaundice is so prevalent in neonatal period ???

9. shunt bilirubin Y&Z protein UDPGT Albumin β-glucuronidase Enterohepatic Circulation Normal Bilirubin Metabolism

10. What’s the distinct metabolic characteristics of bilirubin in newborns comparing with our adults?

11. Neonatal Bilirubin Metabolism 1. Increased bilirubin production in newborns 2. Insufficient binding between bilirubin and albumin 3. Deficient bilirubin conjugation in the hepatocyte 4. Increased enterohepatic circulation of bilirubin 5. Others

12. 1. Increased bilirubin production (1) Increased oxygen partial pressure PO2 bilirubin PO2 RBC RBC

13. 1. Increased bilirubin production (2) Short survival of neonatal erythrocyte Preterm: ﹤70 days Term: 80 days [1] Life span of RBC Adult: 120 days [2] Turnover rate of neonatal hemoglobin: 2 times faster than that of adults

14. heme shunt bilirubin bone marrow precusor 1. Increased bilirubin production (3) Over production of shunt bilirubin

15. Neonatal Bilirubin Metabolism 1. Increased bilirubin production in newborns 2.Insufficient binding between bilirubin and albumin 3. Deficient bilirubin conjugation in the hepatocyte 4. Increased enterohepatic circulation of bilirubin 5. Others

16. GAalbumin bilirubin-albumin complex • low content of serum albumin • different degree of acidosis at birthbinding affinity B A A B B B B B B A B B B A A B A B B serum 2. Insufficient Binding between Bilirubin and Albumin

17. Neonatal Bilirubin Metabolism 1. Increased bilirubin production in newborns 2. Insufficient binding between bilirubin and albumin 3.Deficient bilirubin conjugation in the hepatocyte 4. Increased enterohepatic circulation of bilirubin 5. Others

18. Y carrier protein increases rapidly 5~10 days later conjugation of bilirubin with glucuronic acid • UDPGT reaches the adult’s values 1 week after birth 3. Deficient Bilirubin Conjugation in the Hepatocyte

19. Neonatal Bilirubin Metabolism 1. Increased bilirubin production in newborns 2. Insufficient binding between bilirubin and albumin 3. Deficient bilirubin conjugation in the hepatocyte 4.Increased enterohepatic circulation of bilirubin 5. Others

20. 4. Increased Enterohepatic Circulation of Bilirubin • intestinal flora is not fully developed • abundant β-glucuronidase • delayed excretion of meconium

21. Neonatal Bilirubin Metabolism 1. Increased bilirubin production in newborns 2. Insufficient binding between bilirubin and albumin 3. Deficient bilirubin conjugation in the hepatocyte 4. Increased enterohepatic circulation of bilirubin 5.Others

22. hunger 5. Others cephalohematoma intracranial hemorrhage dehydration acidosis …… hypoxia

23. [2] Pathogenesis : over-production of bilirubin immature liver function Summary [1] Jaundice is much more frequent in neonates

24. Thank you