Transfusion siderosis

It is an orally active iron chelator. It is useful in acute iron poisoning, iron overload in cirrhosis, transfusion siderosis in thalassemia patients. Adverse effects are anorexia, vomiting, altered taste, joint pain and neutropenia. 

Conventional treatments for hemochromatosis and for nutritional iron overload include reduction of dietary iron and periodic removal of blood (phlebotomy) until iron stores are reduced. In transfusion siderosis, it is necessary to eliminate iron via the urine by the intravenous infusion of highly specific chelating agents such as desferral (see Iron Transport Siderophores). This process is painful, laborious, and costly. The development of new orally effective iron chelators is expected. 

Patients with transfusion siderosis require a long-term programme of chelation therapy. In patients who are transfusion-dependent from infancy (thalassaemia major, congenital refractory anaemia) chelation therapy is commenced after 10-20 transfusions at about 3 years of age. In older patients with acquired transfusion-dependent anaemias chelation is commenced after 20 transfusions or when the serum ferritin is 2-3 times the upper limit of normal. 

It is conceivable that iron-catalyzed reactions could occur in some diabetic individuals, since diabetes is found commonly in patients with transfusion siderosis, dietary iron overload, and idiopathic hemochromatosis (McLaren et al, 1983 Phelps et al, 1989). This suggestion is further supported by the observation that desferrioxamine treatment decreases hyperglycemia and lowers hypercholesterolemia and hyperlipidemia in diabetic patients with high ferritin but no hemachromatosis (Cutler, 1989). 

Treatment of chronic iron overload, e.g. haemochro-matosis, patients who are transfusion-dependent due to chronic haemolytic anaemias, thalassaemia and refractory anaemias with transfusional iron overload (siderosis). The goal of therapy is the reduction and maintenance of body iron stores at normal or near-normal levels to avoid the tissue damage associated with iron overload. 

As a result of the crises entailing destruction of the red blood cells and the frequently required blood transfusions, liver siderosis develops. This may subsequently lead to fibrosis in some cases. Episodic cholestasis can be witnessed. In progressive siderosis, treatment with deferoxamine is indicated. Pigment gallstones (s. figs. 

Patients who have received about 100 units of erjdhro-cjdes inevitably develop siderosis of the organs and tissues as a consequence of transfusion-induced iron overload... 

Hemosiderosis is a form of siderosis in which the iron deposits result from hemoglobin breakdown. Hemosiderosis may be focal (a consequence of hemorrhage) or generalized, resulting from a reduced life span of the red cell (repeated blood transfusion, hemolytic anemia, etc.). Hemochromatosis is characterized by cirrhosis, diabetes, and skin pigmentation and probably results from some molecular alteration of iron metabolism. Hemochromatosis will be described in more detail after a discussion of the iron pigments in tissues. 

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