Neonatal and newborn conditions Flashcards
(179 cards)
Is neonatal jaundice common? Esp in who?
Yes mild is common esp in pre-term
Which time scales of neonatal jaundice need investigation?
First 24hr or lasting beyond 2w
What builds up in neonatal jaundice? What are the two types?
Bilirubin Unconjugated Conjugated
What two mechanisms cause unconjugated hyperbilirubinaemia?
Excessive haemolysis or impaired conjugation
What are the 8 causes of unconjugated hyperbilirubinaemia?
Prematurity (immature liver enzymes)
- Rh incompatible (haemolytic disease of the newborn (see notes at bottom). Coomb’s test positive.)
- ABO incompatible (usually milder than Rh)
- Infection (bacterial)
- Bruising (traumatic delivery)
- Hypothyroid (?pituitary disease)
- Breast milk jaundice
- Physiological
What is physiological unconj hyperbil. due to? what might it need treatment with?
- low liver enzyme activity (liver immaturity, particularly in pre-term) or breakdown of foetal haemoglobin. Occasionally needs phototherapy.
What is breast milk jaundice?
otherwise well baby who is breast-fed develops jaundice day 4-7 until week/month 3. Normal coloured stool and urine. Inhibition of liver conjugation enzymes by breast milk. Diagnosis of exclusion- measure split bilirubin to exclude conjugated hyperbilirubinaemia.
What test would be positive in haemolytic disease of the newborn?
Coomb’s test (rhesus)
Why does conjugated hyperbil. occur?
Obstruction of drainage of bile ducts
What are the 4 reasons conj, hyperbil. occurs?
Hepatitis CF Choledocal cyst Biliary atresia
What are the different types of hepatitis that could cause conj. hyperbil/?
A, B, C, CMV Inborn error of metabolism e.g. galactosaemia
Is biliary atresia common?
No 1 in 10,000
What is biliary atresia? What are the signs? What would an investigation show? What is the management and what happens if untreated?
o Persistent jaundice with rising conjugated fraction over weeks. (>20% after 2 weeks = refer, any jaundice persisting after 2 weeks should have both bilirubins checked.) o Pale, chalky stools o Due to absence of intra/extrahepatic bile ducts. o Undiagnosed- liver failure and may die without transplant. o Urgent referral to paediatric hepatologists for assessment, diagnostic isotope scan and surgical correction.
What is the normal breakdown of bilirubin?
RBC breakdown (haem)→ biliverdin→ unconjugated (lipid soluble, can cross BBB) bilirubin → conjugation occurs in liver, conjugated bilirubin is water soluble → enters gut via bile → gut enzymes break it down into urobilinogen → 80% excreted in faeces as stercobilinogen, 2% in urine as urobilin and 18% enter enterohepatic circulation.
Important things to ask in the history of neonatal jaundice?
• Age developed (within 24h investigate) • Risk factors for infection • Fhx e.g. CF, spherocytosis • How is baby? Active, alert, feeding well? Lethargic and must be woken for feeds (sig. jaundice) • Breast feeding?
Examination findings of neonatal jaundice?
• Extent (spreads head down) • Features of congenital viral infection e.g. petechiae, anaemia, hepatosplenomegaly • Dehydrated? • Pale stool • Baby well in general?
Investigations for neonatal jaundice? What is the justification for each?
• Bloods: o FBC (thrombocytopenia = viral infection or IUGR, anaemia = haemolytic disease, neutropenia or neutrophilia in infxn) o CRP (?) o Group and Coombs (ABO and Rh) o TFT o LFT (high ALT suggests hepatitis) o Coag o TORCH screen (for Hep B, CMV) • Urine metabolic screen (inborn errors of metabolism) • Liver USS • Liver isotope scan (r/o biliary atresia in persistent conjugated hyperbilirubinaemia) • ?Urine and CSF infection screen
Management options for neonatal jaundice (5)
Identify cause and severity Phototherapy Exchange transfusions Refer to hepatology if biliary atresia Vitamin K supplement depending on coag screen results
What does phototherapy do in neonatal jaundice?
Blue light 450nm wavelength converts unconjugated bilirubin to biliverdin (an isomer that can be excreted by the kidneys. In rhesus or ABO incompatibility, if bilirubin levels rise significantly despite phototherapy, may need exchange transfusion.)
When are exchange transfusions needed in neonatal jaundice and why?
Severe neonatal jaundice to prevent kernicterus
What is kernicterus?
When free bilirubin crosses BBB, deposited in basal ganglia- acute encephalopathy with irritability, high pitched cry or coma. Can lead to deafness and athetiod cerebral palsy.
What is haemolytic disease of the newborn?
If ABO or Rh incompatible, Maternal IgG crosses placenta, reacts with foetal RBC antigens.
What happens with haemolytic disease of the newborn in utero?
Foetal anaemia can = hydrops (severe oedema)
What is the in-utero management of haemolytic disease of the newborn?
Could have intra-uterine blood transfusion if severe Should be delivered before severe haemolysis





