prehepatisk

Prehepatisk, or prehepatic, is a medical term describing conditions or processes that occur before bilirubin is taken up or processed by the liver. In hepatology, jaundice is commonly categorized as prehepatic, hepatic, or posthepatic, depending on where the bilirubin problem arises. Prehepatic jaundice results from increased production of bilirubin, typically due to accelerated breakdown of red blood cells or ineffective erythropoiesis. The liver's ability to uptake and conjugate bilirubin is usually intact, but the amount of bilirubin entering the liver exceeds its conjugation capacity, leading to an accumulation of unconjugated (indirect) bilirubin in the blood.

Common prehepatic causes include hemolytic anemias (such as autoimmune hemolysis, sickle cell disease, hereditary spherocytosis), thalassemias, and, in newborns, physiologic jaundice due to immature bilirubin conjugation. In severe or chronic cases, increased bilirubin production may be accompanied by anemia or reticulocytosis. Clinical features are dominated by jaundice; dark urine is typically absent because unconjugated bilirubin is not water-soluble, while stool color remains brown because urobilinogen production persists. Laboratory findings show elevated indirect bilirubin with normal or near-normal liver enzymes and alkaline phosphatase; the urinalysis usually shows no bilirubin but increased urobilinogen.

Diagnosis relies on bilirubin fractionation (direct vs indirect) and assessment of reticulocyte count, blood smear, and hemolysis markers. Management focuses on treating the underlying cause of increased red cell destruction and, in newborns, supportive care such as phototherapy for significant unconjugated hyperbilirubinemia. Prognosis is generally favorable with effective treatment of the underlying disorder. Prehepatic jaundice is contrasted with hepatic jaundice, which involves liver dysfunction, and posthepatic jaundice, caused by biliary obstruction.