Depending on the nature of the bilirubin elevated, the condition may be grouped into:-
→ conjugated or Unconjugated hyperbilirubinemia.
A → Congenital Hyperbilirubinemias
They result from abnormal uptake, conjugation or excretion of bilirubin due to inherited defects such as
- The defect is due to conjugation, there is severe deficiency of UDP glucuronyl transferase. The disease is often fatal and the children die before the age of 2.
- Unconjugated bilirubin level increases to more than 20mg/dl, and hence kernicterus results.
- Bilirubin level in blood exceeds 20 mg/dl in Crigler-Najjar syndrome Type 1 and does not exceed 20 mg/dl in Crigler-Najjar syndrome Type 2.
- It is inherited as an autosomal dominant trait.
- The defect is in the uptake of bilirubin by the liver.
- Bilirubin level is usually around 3 mg/dl, and patient is asymptomatic, except for the presence of mild jaundice.
- It is an autosomal recessive trait leading to defective excretion of conjugated bilirubin.
- The disease results from the defective ATP-dependent organic anion transportin bile canaliculi.
- There is a mutation in the MRP-2 protein which is responsible for transport of conjugated bilirubin into bile.
- The bilirubin gets deposited in the liver and the liver appears black. The condition is referred to as Black liver jaundice.
- exact defect is not identified. Bilirubin excretion is defective, but there is no staining of the liver. It is an autosomal recessive condition.
- Called as neonatal hyperbilirubinemia.
- Transient hyperbilirubinemia is due to an accelerated rate of destruction of RBCs and also because of the immature hepatic system of conjugation of bilirubin.
Breast milk jaundice
- In some breast-fed infants, prolongation of the jaundice has been attributed to high level of an estrogen derivative in maternal blood, which is excreted through the milk.
- Dubin Johnson’s syndrome
- Rotor syndrome
- Benign Recurrent intrahepatic Cholestatsis (BRIC)
- Progressive Familial intrahepatic Cholestatsis (FIC)
- Unconjugated Hyperbilirubinemia is associated with > 85% indirect bilrubin or less than 15% of direct bilirubin.
- Hemolytic disorders and increased hemoglobin destruction cause unconjugated or indirect hyperbilirubinemia.
- Biliary atresia and neonatal hepatitis lead to conjugated hyperbilirubinemia.
- Uncojugated hyperbilirubinemias is-Gilbert’s disease, Crigler-Najjarsyndrome.
- Conjugated Hyperbilirubinemias-A. Dubin Johnson’s syndrome, B. Rotor syndrome, c.Benign Recurrent intrahepatic Cholestatsis (BRIC), d.Progressive Familial intrahepatic Cholestatsis (FIC)