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Repeated transfusions of red blood cells may cause transfusional iron overload, a condition that can be effectively treated and reversed with iron chelation therapy.
The most common form of genetic iron overload is hereditary hemochromatosis. Other rare inherited diseases cause iron overload because of defects in iron transport. In hypotransferrinemia/atransferrinemia, impaired erythropoiesis may also be present due to the unavailability of transferrin to transport iron to erythrocytes; this may lead to anemia.
In aceruloplasminemia, a deficiency in ceruloplasmin in macrophages prevents adequate oxidization of Fe2+ to Fe3+, thereby disabling the binding of iron to transferrin in plasma [3, 4] and increasing oxidative stress. The movement of iron from intracellular stores into plasma is impaired, leading to hemosiderosis.
Adapted with permission [5].
Patients with thalassemia major who do not receive iron chelation therapy in conjunction with blood transfusions typically develop clinically apparent iron overload at a young age. In comparison, people with genetic iron overload (homozygous or heterozygous hereditary hemochromatosis) develop iron overload much more slowly.
Acute iron intoxication most commonly occurs in children who consume their mothers' iron tablets and iron poisoning is a leading cause of death from accidental ingestion in children under age 5 [6]. Depending on the amount ingested, circulatory arrest may ensue. The treatment for acute iron poisoning includes gastric lavage, induced vomiting, suction and maintenance of a clear airway, phlebotomy, iron chelation therapy, control of shock with intravenous fluid and electrolyte replacement, correction of acidosis, and red blood cell transfusion.
Diseases of the liver, such as alcoholic liver disease [7] and chronic hepatitis C infection [8] are sometimes associated with increased iron storage, although the mechanisms are unclear.
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References
(1) Piperno A. Classification and diagnosis of iron overload. Haematologica. 1998;83(5):447-55.
(2) Hershko C, Link G, Cabantchik I. Pathophysiology of iron overload. Ann N Y Acad Sci. 1998 ;850:191-201.
(3) Miyajima H. Genetic disorders affecting proteins of iron and copper metabolism: clinical implications. Intern Med. 2002;41(10):762-9.
(4) Sheth S, Brittenham GM. Genetic disorders affecting proteins of iron metabolism: clinical implications. Annu Rev Med. 2000;51:443-6.
(5)Olivieri NF, Brittenham GM. Iron-chelating therapy and the treatment of thalassemia. Blood. 1997;89(3):739-61.
(6) Morris CC. Pediatric iron poisonings in the United States. South Med J. 2000;93(4):352-8.
(7) Pietrangelo A. Iron-induced oxidant stress in alcoholic liver fibrogenesis. Alcohol. 2003;30(2):121-9.
(8) Farinati F, Cardin R, De Maria N, et al. Iron storage, lipid peroxidation and glutathione turnover in chronic anti-HCV positive hepatitis. J Hepatol. 1995;22(4):449-56.
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