The Porphyrias.

Abstract

The porphyrias are a diverse group of metabolic diseases. Major manifestations are episodic neurovisceral attacks of pain or other neurologic features, and/or dermatologic abnormalities. It is essential that a clear diagnosis be established prior to planning management. In our experience, most patients referred with a presumptive diagnosis of "porphyria" do not have true porphyria at all, but rather have syndromes of other etiologies associated with mild, nonspecific increases in urinary porphyrin excretion (secondary porphyrinurias). The management of the acute or inducible porphyrias depends upon prevention and prompt, aggressive management of acute attacks. The latter includes nutrition (at least 300 g/d carbohydrate plus adequate protein), analgesia, and intravenous heme. The management of active porphyria cutanea tarda involves iron depletion by therapeutic phlebotomy and cessation of precipitating or exacerbating factors, especially alcohol and estrogens. When chronic hepatitis C and/or HIV infection are present, they should also be treated. The management of protoporphyria involves ensuring adequate iron stores, and avoidance of hepatotoxic or cholestatic factors. Liver transplantation may be life-saving in the small minority of patients who develop progressive protoporphyric liver disease. A few patients with congential erythropoietic porphyria (Günther's disease) have been treated successfully by transplantation of bone marrow from a normal donor. In the future, this and other forms of porphyria may be treated by specific gene therapy. Such efforts are now under development, but they are not yet ready for human trials in the US.