Jaundice (Icterus)

In jaundice (synonyms: Bilirubin Metabolism Disorder; Cholaemia; Cholemia; Skin Icterus; Icterus; Conjunctival Icterus; Rubinicterus; Sclerae – Yellow; Sclerenic Icterus; Yellow Sclerae; ICD-10-GM R17: Hyperbilirubinemia, with or without jaundice, not elsewhere classified) is jaundice, which can occur as a symptom of many different diseases, especially liver disease. Sclerae (white skin of the eye), skin and mucous membranes turn yellow due to the deposition of bile pigments (mainly bilirubin).

Icterus is caused by a strong increase in bilirubin levels in the blood (= hyperbilirubinemia). Icterus is most easily recognized from bilirubin levels > 2-3 mg/dl (> 51 μmol/l) on the conjunctivae (conjunctiva of the eyes).

Two types of hyperbilirubinemia are distinguished (see below Causes/pathogenesis (disease development):

  • Unconjugated hyperbilirubinemia (= indirect hyperbilirubinemia): elevated total bilirubin with a proportion of direct bilirubin of less than 15%.
  • Conjugated hyperbilirubinemia (= direct hyperbilirubinemia; water-soluble form of bilirubin): concentration of conjugated bilirubin > 2 mg/dl or > 20% of total serum bilirubin.

Three forms/causes of jaundice can be distinguished:

  • Prehepatic icterus – here the cause is before the liver:
    • Etiology (cause): ineffective hematopoiesis/hemolysis with increased bilirubin.
    • Disorder: excess hepatic conjugation capacity (coupling of bilirubin to glucuronic acid).
  • Intrahepatic jaundice (synonym: hepatic icterus) – here the cause is in the liver:
    • Etiology: liver diseasesDisorder: disorders of hepatic conjugation and / or bile flow (= intrahepatic cholestasis).
  • Posthepatic jaundice – here the cause is anatomically located behind the liver, i.e. from the major bile ducts:
    • Etiology: compression/occlusion of large extrahepatic bile ducts.
    • Disorder: disturbance of bile outflow (= extrahepatic cholestasis).

Icterus can also occur in newborns (“neonatal jaundice“). Approximately 60% of newborns have more or less pronounced jaundice in the first days of life. Normally, neonatal jaundice has no clinical significance. It occurs 2-3 days after birth and usually disappears spontaneously (on its own) within 8 days.

Course and prognosis: Course and prognosis depend on the underlying disease. Icterus may also be chronic and result in organ damage.