Overview Hyperbilirubinemia leading to yellowing of skin and eyes classified by ratio of conjugated bilirubin:total bilirubin CB < 20% Gilbert's/Crigler Najjar syndromes physiologic jaundice of newborn hemolysis CB 20-50% viral hepititis CB > 50% drugs (e.g. OCP) Dubin-Johnson/Rotor syndromes primary biliary cirrhosis obstruction (e.g. stone) Pathophysiology hepatocytes convert unconjugated (indirect) bilirubin into conjugated (direct) bilirubin performed by glucuronyl transferase enzyme to make bilirubin water soluble see Heme metabolism topic for normophysiology bilirubin is not toxic at moderate levels high increases can result in kernicterus and death deposition of bilirubin in the brain Types hemolytic destruction of RBCs than conjugation/excretion system can handle can result from hereditary hemolytic anemias, Rh incompatibility, ect. obstructive intrahepatic or bile duct block does not allow body to excrete bilirubin can result from oral contraceptives gallbladder stone carcinoma of the head of the pancreas hepatocellular damage to liver (i.e. hepatitis, cirrhosis) ↓ ability of conjugation/excretion system to handle normal bilirubin load Jaundice TypeHyper bilirubinemiaUrine BilirubinUrine UrobilinogenHepatocellularConjugated or unconjugated↑Normal/↓ObstructiveConjugated↑↓HemolyticUnconjugatedAbsent↑