Physiology

  • RBC hemoglobin breakdown -> unconjugated (indirect) bilirubin
  • Unconjugated (indirect) bilirubin -> liver -> conjugated (direct) bilirubin
  • Conjugated (direct) bilirubin -> Eliminated in stool

Causes of Hyperbilirubinemia

  • Increased RBC turnover
    • Sepsis
    • Rh incompatibility
    • RBC disorders
    • Maternal diabetes
    • Scalp hematoma
  • Decreased/slow conjugation by the liver
    • Peaks around day 5 of life
    • Congenital liver disorders
      • Gilbert/Crigler Najjar Syndromes
    • Breast milk jaundice
      • Breast milk inhibits conjugation of bilirubin
  • Decreased excretion
    • Bowel obstruction
    • Breast feeding failure (dehydration)
      • Decreased stool output results in reabsorbed bilirubin

Kernicterus

  • Brain damage from severe hyperbilirubinemia (>25 mg/dL)
  • Compare measured bilirubin to established nomogram
  • Treatment is phototherapy
    • (Worst case scenarios require exchange transfusion)

Additional Reading