Liver

Question 1

what components make up a liver ‘function’ test (LFT)?

Answer 1

• Bilirubin: total and ‘split’ bilirubin (direct (conjugated) and indirect (unconjugated))
• ALT/AST: elevated in hepatocellular damage (hepatitis)
• alkaline phosphatase (ALP) and gamma glutamyl transferase (GGT) > elevated in biliary disease
• could also do albumin and coagulation screen.

Question 2

what are the clinical manifestations of paediatric liver disease?

Answer 2

• Jaundice
• incidental finding of abnormal blood test
• symptoms/signs of chronic liver disease

Question 3

what type of bilirubin (conjugated or unconjugated) is present in:
a) pre-hepatic jaundice
b) intra-hepatic jaundice
c) post-hepatic jaundice (cholestasis)

Answer 3

a) mostly unconjugated
b) mixture of both
c) mostly conjugated

Question 4

what are causes of early neonatal jaundice (< 24 hours old)?

Answer 4

• always pathological
• causes: haemolysis, sepsis

Question 5

what are some causes of intermediate neonatal jaundice (24hrs-2 weeks old)?

Answer 5

• physiological
• breast milk
• sepsis
• haemolysis

Question 6

what are some causes of prolonged neonatal jaundice (> 2 weeks old)?

Answer 6

• extrahepatic obstruction e.g. biliary atresia, choledochal cyst, Alagille syndrome > conjugated
• neonatal hepatitis > conjugated
• hypothyroidism > unconjugated
• breast milk > unconjugated

Question 7

describe ‘physiological’ jaundice, what causes it?

Answer 7

• shorter RBC life span in infants (80-90 days)
• relative polycythaemia
• relative immaturity of liver function

Causes unconjugated jaundice that develops after first 24 hrs of life.

Question 8

what causes breast-milk jaundice?

Answer 8

• Exact reason for prolongation of jaundice in breastfed infants is unclear:
• inhibition of UDP by progesterone metabolite?
• increased enterohepatic circulation?

Causes unconjugated jaundice that an persist up to 12 weeks.

Question 9

what are some complications of early infant jaundice?

Answer 9

Kernicterus:
- unconjugated bilirubin is fat-soluble (water insoluble) so can cross blood-brain barrier
- neurotoxic and deposits in brain
- early signs: encephalopathy > poor feeding, lethargy, seizures
- late consequences: severe choreoathetoid cerebral palsy, learning difficulties, sensorineural deafness

Question 10

treatment for unconjugated infant jaundice

Answer 10

• phototherapy
• visible light (450nm wavelength) converts bilirubin to water soluble isomer (photoisomerisation)

Question 11

Conjugated jaundice in infants is always abnormal and always requires further investigation. What is the most important test in prolonged jaundice?

Answer 11

A ‘split’ bilirubin test

Question 13

What is biliary atresia and how does it present?

Answer 13

• Congenital fibro-inflammatory disease of bile ducts leading to destruction of extra-hepatic bile ducts.
• presents with prolonged conjugated jaundice, pale stools and dark urine.
• most common indication for liver transplantation in children.

Question 14

what is the treatment for biliary atresia?

Answer 14

Kasai Portoenterostomy
- best results if performed before 60 days (< 9 weeks old)

Question 15

how is biliary atresia diagnosed?

Answer 15

• split bilirubin test
• stool colour
• ultrasound
• liver biopsy