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Iron overload may develop in transfusion-dependent patients receiving red cells
over a long period.
Iron overload is a major concern in patients with congenital and acquired anemias
for whom regular transfusions are needed
- under normal conditions, iron absorption and loss are balanced at approx1
mg/day. Transfused blood contains 200-250 mg of iron per unit
- hence, patients with beta-thalassemia major (TM) or other refractory
anemias receiving 2-4 units of blood per month have an annual intake of
5000-10 000 mg of iron or 0.3-0.6 mg/kg per day. The body has no mechanism
for excreting this excess iron.
- regular iron cell transfusions may increase this iron load by up
to 10 g per year
Symptoms are similar to those seen in haemochromatosis with:
- endocrine dysfunction - for example, diabetes mellitus
- liver cirrhosis
- cardiac failure
- growth failure in children
- delayed onset of puberty
- skin pigmentation
- serum ferritin to estimate body iron stores
- desferrioxamine as a chelating agent, with vitamin C to enhance the therapeutic
- iron overload may be prevented or treated with a chelating agent that
complexes iron and allows excretion of chelator-iron complexes from the
body. The most widely used chelating agent is desferrioxamine mesylate
(desferrioxamine) administered subcutaneously or intravenously
- normal body stores are 3-4.0 g; daily losses are 1 mg
- problems usually develop once more than 30 g of iron accumulate
- each unit of red cells has 200 mg of iron
- siderosis describes the deposition of iron in tissues
- haemosiderosis describes the accumulation of excess haemosiderin
- haemosiderin is an iron-storage complex. It is always found within
cells and appears to be a complex of ferritin, denatured ferritin and
- iron within deposits of hemosiderin is very poorly available to
supply iron when needed. Hemosiderin can be identified histologically
with "Prussian-blue" stain.
- excessive accumulation of hemosiderin is usually detected within
cells of the mononuclear phagocyte system (MPS) or occasionally within
epithelial cells of liver and kidney.
- Kushner JP, Porter JP, Olivieri NF. Secondary iron overload. Hematology
/ the Education Program of the American Society of Hematology. American Society
of Hematology. Education Program 2001;2001(1):47-61.
- Hoffbrand AV et al. How I treat transfusional iron overload. Blood. 2012
Last reviewed 01/2018