Newborn Lectures Week 8

Question 1

Describe the pathway of getting from heme to bilirubin

Answer 1

heme –> (heme oxygenase) –> biliverdin –> (biliverdin reductase) –> bilirubin

Question 2

Describe the conjucation on bilirubin pathway

Answer 2

Bilirubin is conjugated in hepatocyte by UDPGT & is excreted into bile

Question 3

what happens to bilirubin in an infant gut when excreted into bile?

Answer 3

hydrolysed back into unconjucated bilirubin and re-enters enterohepatic circulation

Question 4

How is bilirubin eliminated?

Answer 4

1. cecal bacteria converts it to stercobilin

2. converted by kidneys to urobilin

Question 5

3 causes of physiologic jaundice?

Answer 5

1. immaturity of liver UDGPT
2. Lack of cecal bacteria so more re-enters enterohepatic circulation
3. relative increased load of RBCs

Question 6

Name some causes of indirect hyperbilirubinemia in infants? (10)

Answer 6

1. hemolytic dx (ABO, Rg, rare blood types)
2. Hereditary spherocytosis, elliptocytosis
3. G6PD def, Pyruvate kinase def
4. Hemoglobinopathies (thalasemia)
5. Sepsis
6. DIC
7. Hematoma, polycythemia
8. Prematurity
9. Inborn errors of metabolism
10. Hypothyroidism