Neonate Jaundice

Question 1

Solubility of unconjugated bilirubin

Answer 1

Insoluble in water but soluble in lipids

Question 2

How is unconjugated bilirubin transported?

Answer 2

Bound to albumin

Question 3

Which enzyme conjugates bilirubin in the liver?

Answer 3

UDP-glucoronyl transferase

Question 4

Importance of conjugated bilirubin?

Answer 4

Water soluble so it can be excreted in bile

Question 5

How is bile excreted?

Answer 5

In bowel as stercobilinogen and in urine as urobilinogen

Question 6

Define enterohepatic circulation

Answer 6

Some bilirubin is converted back into unconjugated bilirubin in the gut and reabsorbed back into the blood streaming transported to liver to be metabolised again.

Question 7

At what level of bilirubin do babies become clinically jaundiced

Answer 7

80µmol/L (micromoles per litre)

Question 8

What percentage of new-borns become visibly jaundiced?

Answer 8

50%

Question 9

3 causes of physiological jaundice in newborns

Answer 9

1. Shorter lifespan of red blood cells.
2. Increased enterohepatic circulation
3. immature hepatic enzymes
   (4. bruising may also contribute)

Question 10

Treatment of physiological jaundice in new borns

Answer 10

Phototherapy converts unconjugated bilirubin into conjugated bilirubin which is soluble and can be excreted in urine.

Question 11

Risk factor that makes physiological jaundice more common

Answer 11

Breastfeeding

Question 12

Timeframe of physiological jaundice in newborns

Answer 12

Jaundice appears at around 24hrs and resolves by 2 weeks of age

Question 13

4 Pathological causes of jaundice

Answer 13

Infection, hemolysis, hypothyroidism. bruising