1、The Metabolic Characteristics of Bilirubin in NewbornsWu jinlinDepartment of PediatricsWest China Second University Hospital Sichuan University Baby on Phototherapy Introduction of Neonatal Jaundicev Jaundice is quite common in neonatal period1 60% of term infants and 80% of preterm infants2 Visible
2、 jaundice from sclera, mucosa and skin Introduction of Neonatal Jaundicev Can cause serious 1 Actue phaserespiratory failure bilirubin encephalopathy neonatal death2 lifelong neurologic sequelae kernicterus cerebral palsy epilepsy mental retardation auditory and visual disfunctions Why jaundice is s
3、o prevalent in neonatal period ?The Metabolic Characteristics of Bilirubin in Newborns Normal Bilirubin Metabolism Y&Z proteinUDPGT-glucuronidase Albumin shunt bilirubinEnterohepatic Circulation Whats the distinct metabolic characteristics of bilirubin in newborns comparing with our adults? 1. Incre
4、ased bilirubin production in newborns 2. Insufficient binding between bilirubin and albumin 3. Deficient bilirubin conjugation in the hepatocyte 4. Increased enterohepatic circulation of bilirubinNeonatal Bilirubin Metabolism5. Others (1) Increased oxygen partial pressure1. Increased bilirubin produ
5、ction PO2 PO2RBCRBCbilirubin1 Life span of RBCPreterm: 70 daysTerm: 80 daysAdult: 120 days2 Turnover rate of neonatal hemoglobin: 2 times faster than that of adults (2) Short survival of neonatal erythrocyte1. Increased bilirubin production (3) Over production of shunt bilirubin 1. Increased bilirub
6、in production hemebone marrow precusorshunt bilirubin1. Increased bilirubin production in newborns 2.Insufficient binding between bilirubin and albumin 3. Deficient bilirubin conjugation in the hepatocyte 4. Increased enterohepatic circulation of bilirubinNeonatal Bilirubin Metabolism5. Others2. Ins
7、ufficient Binding between Bilirubin and Albumin v low content of serum albumin GA albumin bilirubin-albumin complex v different degree of acidosis at birth binding affinity BAAAABABBBBBBBBABBBserum1. Increased bilirubin production in newborns 2. Insufficient binding between bilirubin and albumin 3.D
8、eficient bilirubin conjugation in the hepatocyte 4. Increased enterohepatic circulation of bilirubinNeonatal Bilirubin Metabolism5. Others3. Deficient Bilirubin Conjugation in the Hepatocyte v UDPGTreaches the adults values 1 week after birth v Y carrier proteinincreases rapidly 510 days laterconjug
9、ation of bilirubin with glucuronic acid 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 bilirubinNeonatal Bilirubin Metabolism5. Others4. Increased Entero
10、hepatic Circulation of Bilirubinvintestinal flora is not fully developed vabundant -glucuronidase vdelayed excretion of meconium 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 bilirubinNeonatal Bilirubin Metabolism5.Others5. Othersdehydrationacidosisintracranial hemorrhagecephalohematomahunger hypoxia Summary1 Jaundice is much more frequent in neonates2 Pathogenesis : over-production of bilirubin immature liver function
