Hepatic porphyrias. Current concepts.

Acute intermittent porphyria, variegate porphyria, and hereditary coproporphyria are hepatic porphyrias due to enzyme defects that are inherited as autosomal dominants. Porphyria cutanea tarda is considered an acquired disorder. Similar drugs or circumstances are precipitants of acute attacks in all three inherited hepatic porphyrias. The respective biochemical abnormalities are identifiable by simple, readily available laboratory tests. Management of patients with any of the inherited hepatic porphyrias is directed primarily toward prevention of attacks through avoidance of precipitants and through a diet high in carbohydrate. Therapy for porphyria cutanea tarda includes interdiction of alcohol use and repeated phlebotomy.