Jaundice

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