| Popis: |
The ferrochelatase deficiency in protoporphyria leads to accumulation of protoporphyrin in erythrocytes and liver. Consequences are protoporphyrinemia with photosensitivity and liver damage (fibrosis, cirrhosis) with cholestasis. The latter are unpredictable and can be observed in about 10% of the patients. Protoporphyrin, the physiological main component of hepatocellular porphyrins, has a hepatotoxic effect in the high-concentrated crystalline storage form. The obligatory hepatobiliary excretion of the lipophil, erythropoietic increased accumulating protoporphyrin in protoporphyria strains the excretory function of the liver. Its restriction is followed by an exzessive protoporphyrin accumulation, which leads to protoporphyrin-induced, progressive cholestatic cirrhosis, icterus, and aggravation of the extrahepatic protoporphyrinemic cutaneous manifestation. In case of hepatobiliary complications a coproporphyria of diagnostic relevance develops with inversion of isomers. Simultaneously, the fecal protoporphyrin excretion decreases. After liver transplantation hyperbilirubinemia, protoporphyrinemia and coproporphyrinuria significantly went down. A protoporphyrinemia of about 20% of preoperative values reflects the persisting hereditary enzyme defect and the continuity of the metabolic disease. |
