Jaundice

Question 1

How is neonatal jaundice classified?

Answer 1

By onset.

Jaundice less than 24 hours of age
Always pathological likely due to haemolysis or congenital infection.

Jaundice at 2 days to 2 weeks of age
May be pathological or normal

Jaundice at greater than 2 weeks of age
Always pathological.
Jaundice in babies over 2 weeks (or 3 weeks in preterm) is called persistent neonatal jaundice.

It may be caused by biliary atresia (conjugated) or may be unconjugated in which case there is a variety of causes.

Question 2

What are the likely causes of jaundice in neonates less than 24hrs?

Answer 2

Haemolytic disorders: rhesus haemolytic disease, ABO
incompatibility, spherocytosis and G6PD deficiency.

Congenital infection: should have other abnormal signs such as growth restriction, hepatosplenomegaly and purpura

Question 3

What are the likely causes of jaundice in neonates between 24hrs and 2 weeks?

Answer 3

Physiological jaundice
Breast milk jaundice: multifactorial causes
Dehydration
Infection

Question 4

What are the likely causes of jaundice in neonates greater than 2 weeks?

Answer 4

Conjugated = Biliary atresia/Intrahepatic biliary hypoplasia needs surgical repair to prevent long term damage. Neonatal hepatitis syndrome.

Unconjugated = breast milk jaundice, infection or congenital hypothyroidism.

Conjugated = dark urine and pale stools

Question 5

What is the major complication with high bilirubin levels?

Answer 5

If there is an excess of unconjugated bilirubin that saturates the albumin then it is free to cross the BBB and deposit itself in the basal ganglia, causing kernicterus.

Kernicterus is an encephalopathy which presents as poor feeding, irritability and increased muscle tone.

If not treated promptly it can cause death or long term complications: CP, sensorineural hearing loss and LD.

Question 6

How should you manage a neonate with jaundice?

Answer 6

Assess severity of jaundice by examination and look at the rest of the clinical picture.

Likely physiological jaundice - reassure and give advice

Unsure/pathological - measure bilirubin level using a transcutaneous bilirubinometer. If raised test serum. (note younger than 24hrs always test serum.

Question 7

What methods can be used to treat pathological jaundice?

Answer 7

Phototherapy: (wavelength 450nm)
Is used to convert unnconjugated bilirubin in to a harmless water soluble pigment. The amount of treatment received is related to the bilirubin level.

Exchange transfusion:
It involves transfusing the child with donor blood up to twice its circulating volume (so effectively exchanged twice). The aim is to remove circulating bilirubin and antibody-coated RBCs, replacing them with RBCs compatible with maternal serum and providing albumin with new bilirubin binding sites.

Exchange transfusions are only done when there are very high bilirubin levels as they carry significant mortality risk.

If underlying infection treat it.

Question 8

Which type of hepatitis virus is most likely to cause jaundice as a congenital infection.

Answer 8

Hep C.

Hep A is faeco-oral transmission therefore cannot be congenital.

Hep B and C are blood born.
Hep B however is often asymptomatic in neonates but 30-50% will suffer from chronic Hep B with 10% developing cirrhosis.