Neonatal Liver Disease ✅ Flashcards
What proportion of term babies have transient jaundice 3-5 days after birth?
Around 2/3
What is often the underlying mechanism of unconjugated jaundice in neonates?
Immaturity of the hepatic enzyme glucuronosyltransferase
What is the enzyme glucuronosyltransferase responsible for?
Glucuronidation of bilirubin
What can cause unconjugated jaundice in the neonatal period?
- Breastmilk jaundice
- Haemolysis
- Sepsis
- Hypothyroidism
What is often the underlying mechanism in conjugated jaundice in neonates?
Hepatic dysfunction due to a number of potential causes
What should be measured in babies with significant jaundice?
Bilirubin level with fractional breakdown of the conjugated and unconjugated components
What are Crigler-Najjar types I and II?
Rare autosomal recessive disorders which cause intensive unconjugated hyperbilirubinaemia in the first days of life, which persists after
What is the underlying problem in Crigler-Najjar syndrome type I?
No UDP-glucuronosyltransferase
What is the problem with hyperbilirubinaemia in Crigler-Najjar syndrome type I?
It is very severe despite phototherapy, and may result in kernicterus
How is a diagnosis of Crigler-Najjar syndrome type I made?
DNA analysis
How is Crigler-Najjar syndrome type 1 acutely treated?
Exchange transfusion
What is the long term treatment for Crigler-Najjar syndrome type I?
Liver transplantation
Can Crigler-Najjar syndrome type I be treated with phenobarbital?
No, there is no response to phenobarbital
How does Crigler-Najjar syndrome type II differ from type I?
In type II, some UDP-glucuronosyltransferase is present, so hyperbilirubinaemia is less severe
How is Crigler-Najjar syndrome type II managed?
Phenobarbital (causes marked decreased in serum bilirubin)
How does phenobarbital help in Crigler-Najjar syndrome type II?
It causes cytochrome P450 enzyme induction
What are likely to be helpful in the future management of Crigler-Najjar syndrome?
Therapies based on gene and cell transfer techniques
What is conjugated hyperbilirubinaemia defined as in neonates?
Serum conjugated bilirubin of greater than 25% of the total, or >25µmol/L
What is the most common cause of conjugated neonatal jaundice?
Cholestasis
What causes neonatal cholestasis?
Impairment of bile excretion caused by defects in intrahepatic production or transmembrane transport of bile, or mechanical obstruction to bile flow
What do the biochemical features of cholestasis reflect?
Retention of components of bile within the serum (bilirubin, bile acids, and/or cholesterol)
How to patients with conjugated jaundice classically present?
- Jaundice
- Pale (acholic) stool
- Dark urine
Why does conjugated jaundice present with pale stools?
As no bilirubin reaches the GI tract
Why does conjugated jaundice present with dark urine?
Due to excretion of water-soluble conjugated bilirubin in the urine
What is the most common cause of neonatal liver disease?
Biliary atresia
How does biliary atresia present?
- Conjugated jaundice
- Acholic stools
- Hepatomegaly
What is bile essential for?
Carrying waste from the liver and promoting absorption of fats and fat-soluble vitamins
What does biliary atresia result in if not corrected?
Chronic liver failure
How is biliary atresia surgically corrected?
The Kasai portoenterostomy - attaching porta hepatis to a loop of small intestine
What is the purpose of the Kasai portoenterostomy?
To allow diversion of bile from the residual small bile ducts
How effective is the Kasai portoenterostomy?
Up to 60% will achieve biliary drainage (bilirubin <20µmol/L) within 6 months
What is the prognosis for children with biliary atresia who have undergone a successful Kasai portoenterostomy?
Most will reach adolesence with a good quality of life (but with cirrhosis/evidence of portal hypertension) without undergoing liver transplantation
Which congenital infections are associated with conjugated jaundice and hepatomegaly?
- CMV
- Toxoplasmosis
- Rubella
- Syphilis
What other infections can cause cholestasis?
Any infection acquired around the time of birth, e.g. herpes simplex, varicella zoster, or any bacterial infection