Chen Dapeng MD, PhD Pediatric Department West China Second University Hospital

To understand the characteristics of neonatal bilirubin metabolism. Objective

Jaundice( 黄疸 )

Term baby (>37w) 50% Incidence in Newborn Preterm baby(<37w) 80%

Core of Bilirubin Metabolism Unconjugated bilirubin ( 未结合胆红素 ) Conjugated bilirubin （结合胆红素） glucuronic acid （葡萄糖醛酸）

Metabolism of Bilirubin

Red Blood Cell 1. Increase of bilirubin production Adult 3.8mg/L Newborn 8.5mg/L

RBC life span 120 d 80 d

RBC Quantity 4.5x10 12 /L6.5x10 12 /L

2.Lack of Albumin( 白蛋白 )

3.Poor hepatic function

Unconjugated Bilirubin Y/Z Protein(Y/Z 蛋白 )

Unconjugated Bilirubin glucuronyl transferase( 葡萄糖醛酸转移酶 ) Conjugated bilirubin

4.Increasing of Enterohepatic circulation ( 肠肝循环 )

Enterohepatic circulation Definition: Circulation of bilirubin, which was absorbed from the intestine and carried to the liver, where it was secreted into the bile and again enter the intestine.

Neonatal Enterohepatic circulation Glycuronidase 葡萄糖醛酸苷酶

1. Increase of bilirubin production 2. Lack of albumin 3. Poor hepatic function 4. Increase of enterohepatic circulation Summary of Neonatal Bilirubin Metabolism

Physical and Pathologic Jaundice of Newborn