approach to the yellow baby

Question 1

ALT/AST

what do they stand for

Answer 1

alanine aminotransferase/aspartate aminotransferase

Question 2

elevated ALT/AST

Answer 2

hepatocellular damage - hepatitis

Question 3

typical ways in which liver disease presents in children

Answer 3

jaundice

incidental finding on blood test

rare - other symptoms/signs of CLD

Question 4

jaundice

Answer 4

yellow discolouration of skin and tissues due to accumulation of bilirubin

usually visible when total bilirubin >40-50 umol/l

Question 5

pre-hepatic jaundice

Answer 5

mostly unconjugated bilirubin

increased breakdown RBC and so too much unconjuagted bilirubin

Question 6

intrahepatic jaundice

Answer 6

mixed unconjugated/conjuagted

problem with liver, it’s not conjugating the bilirubin as much as it should be and also not excreting it effectively into bile

Question 7

post-hepatic jaundice (cholestasis)

Answer 7

mostly conjugated bilirubin

problem lies with bile being able to get out of liver and getting to small intestine to be excreted. obstruction/blockage stopping bilirubin getting out of liver/bile ducts

Question 8

neonatal jaundice: early (<24hrs old)

Answer 8

always pathological

causes: haemolysis, sepsis

Question 9

neonatal jaundice: intermediate (24hrs-2wks) causes

Answer 9

physiological
breast milk
sepsis
haemolysis

Question 10

neonatal jaundice: prolonges (>2wks) causes

Answer 10

extrahepatic obstruction
neonatal hepatitis
hypothyroidism
breast milk

Question 11

physiological jaundice

Answer 11

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

unconjugated jaundice
develops after 1st day of life

Question 12

breast milk jaundice

Answer 12

exact reason unclear - inhibition of UDP by progesterone metabolite? increased enterohepatic circulation?

unconjugated jaundice
can persist up to 12wks

Question 13

kernicterus

Answer 13

unconjugated bilirubin is fat-soluble (water insoluble) so can cross blood-brain barrier

neurotoxic and deposits in brain

Question 14

kernicterus signs

Answer 14

early signs: encephalopathy - poor feeding, lethargy, seizures

late consequences - severe choreoathetoid cerebral palsy, learning difficulties, sensorineural deafness

Question 15

phototherapy

Answer 15

treatment for unconjugated jaundice

visible light (not UV) converts bilirubin to water soluble isomer (photoisomerisation)

Question 16

other causes of early/intermediate unconjugated infant jaundice

Answer 16

sepsis

haemolysis: ABO incompatibility, Rhesus disease, red cell membrane defects

abnormal conjugation - Gilbert’s disease

Question 17

prolonged infant jaundice

Answer 17

jaundice persisting beyond 2 weeks of life (3wks for preterm infants)

Question 18

causes of prolonged infant jaundice: conjugated

Answer 18

anatomical (biliary obstruction)

neonatal hepatitis

Question 19

causes of prolonged infant jaundice: unconjugated

Answer 19

hypothyroidism

breast-milk jaundice

Question 20

what is most important test in prolonged jaundice

Answer 20

split bilirubin

Question 21

causes of prolonged infant jaundice: biliary obstruction

Answer 21

biliary atresia: conjugated jaundice, pale stools

choledochal cysts: conjugated, pale stools

alagille syndrome: intrahepatic cholestasis, dysmorphism, congenital cardiac disease

Question 22

what always needs assessed in infants with prolonged jaundice

Answer 22

stool colour

Question 23

biliary atresia

Answer 23

congenital fibro-inflammatory disease of bile ducts leading to destruction of extra-hepatic bile ducts

presents with prolonged, conjugated bilirubin
pale stools, dark urine

Question 24

biliary atresia treatment

Answer 24

kasai portoenterostomy

best results if performed before 60 days (<9wks)

Question 25

what is assessment of prolonged infant jaundice primarily targeted at

Answer 25

diagnosing patients with biliary atresia early

Question 26

causes of prolonged infant jaundice: neonatal hepatitis

Answer 26

alpha-1-antitrypsin deficiency 
galactosaemia 
urea cycle defects
haemochromatosis
glycogen storage disorders
hypothyroidism 
viral hepatitis