Where you go yellow. Technically, its a build up of bilirubin in the body.
Can be caused by a variety of things:
- Physiological neonatal: relatively common in premature infants. (membrane between the blood and the brain is really thin in babies, so unconjugated bilirubin gets into the brain)
- Structural: Biliary Atresia – where the bile duct fails to develop
- Functional: Congenital metabolic defects involving the liver
Can be classified into 3 types:
In these there is excess bilirubin from the break down of blood cells – Haemolysis. Because the excess bilirubin is unconjugated (and thus insoluble) it cant be excreted so the bile contains so much bilirubin it puts the person at risk of gall stones.
Caused by hepatic disorders such as:
- Acute viral hepatitis
- Drug induced liver injury
- Alcoholic hepatitis
- Intrahepatic bile duct loss
The excess bilirubin is predominantly conjugated (and so soluble), and so is excreted in the urine and causes dark urine.
Inteferes with biliarry drainage, the excess conjugated bilirubin produces dark urine and pale stools.
Clinical and Associated Features
Obviously the most important feature is yellowing, of skin, of the whites of the eyes. Others you might experience include
Clues to pathophysiology:
- Pre-hepatic - urine and poo normal colour, itchy, not very yellow, as unconjugated bilirubin is not soluble, nor as yellow.
- Hepatic - urine normal colour, poo normal or pale, itchy, not very yellow.
- Post-hepatic - urine dark, poo pale, itchy, very yellow - the conjugated bilirubin is getting stuck and going into the blood, so the poo isn't getting any, but the urine is getting loads.