Causes of Jaundice
Jaundice (yellow discolouration from bilirubin deposition) is classified as pre-hepatic, hepatic, or post-hepatic. This three-level classification guides investigation and management.
✦ The Mnemonic
"Pre-Hepatic, Hepatic, Post-Hepatic — Progress Through Hierarchy"
Pre-hepatic (haemolysis) · Hepatic (hepatocellular) · Post-hepatic (obstructive)
Clinical Breakdown
Bilirubin pathway: haem → unconjugated bilirubin (fat-soluble, albumin-bound) → liver conjugation → conjugated bilirubin (water-soluble) → bile → intestine → urobilinogen (some reabsorbed, some excreted in urine; some converted to stercobilin = brown stool colour).
Pre-hepatic: unconjugated bilirubin raised; NO bilirubinuria (unconjugated is fat-soluble, not filtered); raised urinary urobilinogen; DARK stools. Post-hepatic: conjugated bilirubin raised; bilirubinuria (dark urine); absent urinary urobilinogen; PALE stools (no stercobilin).
Post-hepatic causes: intraluminal (gallstones in CBD), mural (cholangiocarcinoma, primary sclerosing cholangitis), extramural (pancreatic head carcinoma — painless progressive jaundice + palpable gallbladder = Courvoisier's sign). Hepatic causes: viral hepatitis (A–E), alcoholic hepatitis, autoimmune hepatitis, Wilson's disease, haemochromatosis, drug-induced (paracetamol, isoniazid, statins).
⭐ Clinical Pearl
Courvoisier's law: 'In the presence of obstructive jaundice, a palpable gallbladder is unlikely to be due to gallstones' — because chronic gallstone disease causes a thick-walled, contracted, non-distensible gallbladder. A palpable gallbladder with painless jaundice = cancer of the head of the pancreas until proven otherwise.