Page 71 - Essential Haematology

Chapter 4 Iron overload / 57

■ Iron overload is caused by excessive transferrin receptor 2 and ferroportin).
absorption of iron from food (genetic Repeated venesections are used to reduce
haemochromatosis) or by repeated blood the body iron burden.
transfusions in patients with refractory ■ Transfusional iron overload most frequently SUMMARY

anaemias. Each unit of blood contains occurs in thalassaemia major but also in
200 – 250 mg of iron. other transfusion dependent refractory
■ Excess iron absorbed from the anaemias (e.g. some cases of

gastrointestinal tract accumulates in the myelodysplasia, sickle cell anaemia,
parenchymal cells of the liver, endocrine primary myelofi brosis, red cell aplasia and
organs and, in severe cases, the heart. aplastic anaemia).

■ Transfusional iron overload causes damage ■ Cardiac failure or arrhythmia caused by

to these organs and also iron accumulation cardiac siderosis, best detected by MRI,
in macrophages of the reticuloendothelial is the most frequent cause of death from
system. transfusional iron overload.

■ Genetic haemochromatosis is usually ■ Treatment is with iron chelating drugs:

caused by homozygous mutation deferoxamine (given subcutaneously or
(845G → A) of the HFE gene causing a low intravenously), deferiprone or deferasirox

serum hepcidin level. Rarer forms exist (which are both active by mouth).
caused by mutations of other genes Combinations of chelators are also
coding for proteins (hemojuvelin, hepcidin, employed.
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