The acute porphyrias

Abstract

The porphyrias are a group of metabolic disorders that arise from disturbances on the haem biosynthetic pathway. The acute hepatic porphyrias, including acute intermittent porphyria and variegate porphyria, may result in potentially fatal acute attacks characterised by autonomic, cerebral and motor dysfunction. An acute attack is confirmed by demonstrating elevated urinary levels of porphobilinogen. Further testing requires a combination of biochemical and molecular testing in an expert reference laboratory. Haem arginate is highly effective in terminating an acute attack and should be administered early. Since acute attacks are frequently precipitated by medication, care is needed in choosing medication for these patients. Two other forms of porphyria, though not associated with acute attacks, are relevant to the hepatologist. Erythropoietic protoporphyria may be associated with cholelithiasis and liver failure, whereas porphyria cutanea tarda is common, treatable and strongly associated with the presence of liver disease of various forms. © Touch Briefings 2012.