Excessive red cell breakdown overwhelms the livers ability to conjugate
Any bilirubin that manages to become conjugated will be excreted normally, unconjugated bilirubin remains in the bloodstream to cause the jaundice
Causes include - haemolysis of all causes, haemolytic anaemias, malaria, HUS, sickle cell crisis (triggered by infection)
Hepatic
Dysfunction of the hepatic cells
The liver loses the ability to conjugate bilirubin, but in cases where it may also become cirrhotic, it compresses the intra-hepatic portions of the biliary tree to cause a degree of obstruction
This leads to both unconjugated and conjugated bilirubin in the blood
Causes include - acute liver failure, alcoholic hepatitis, cirrhosis (decompensated), bile duct loss (PBC, PSC), pregnancy, hepatitis A and E (occasionally Hep B), malaria, enteric fever
Post-hepatic
Obstruction of biliary drainage
The bilirubin that is not excreted will have been conjugated by the liver - conjugated bilirubin in blood
Causes include - congenital biliary atresia, gallstones blocking CBD, strictures blocking CBD, tumours e.g. carcinoma at head of pancreas, ascending cholangitis, Helminths
Clinical presentation
Yellow sclera
Pale stools
Dark urine
May be associated with
Itch
Weight loss
Abdominal pain
Ascites
Investigations
USS first line
If USS identifies dilated intra and/or hepatic biliary tree - MRCP +/- ERCP
If USS identifies abnormal lesions - CT
If USS identifies cirrhosis - bloods (virology and immunology), may require US guided liver biopsy
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