Iron deficiency anaemia

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Iron deficiency anaemia



Iron


Iron is a constituent of haemoglobin and rate limiting for erythropoiesis. The metabolism of iron in the body is dominated by its role in haemoglobin synthesis (Fig 12.1). Normally, the total iron content of the body remains within narrow limits: absorption of iron from food (usually up to 3–4 mg/day) must replace any iron losses. Iron is not excreted as such but is lost in desquamated cells, particularly epithelial cells from the gastrointestinal tract. Menstruating women will lose an additional highly variable amount of iron, and in pregnant women the rate of iron loss is about 3.5 times greater than in normal men. The storage forms of iron, ferritin and haemosiderin, constitute about 13% of total body iron. The small peptide hepcidin plays a key role in iron metabolism and absorption (see p. 36).





Causes


The likely cause will vary with the age, sex and geographic location of the patient (Table 12.1). Iron deficiency is usually caused by long-term blood loss, most often gastrointestinal or uterine bleeding and less commonly bleeding in the urinary tract or elsewhere. Particularly in elderly patients, deficiency may be the presenting feature of gastrointestinal malignancy (Fig 12.2). Hookworm infection is the commonest cause of iron deficiency worldwide. Malabsorption and increased demand for iron, as in pregnancy, are other possible causes. Poor diet may exacerbate iron deficiency but is rarely the sole cause outside the growth spurts of infancy and teenage years.



Jun 12, 2016 | Posted by in HEMATOLOGY | Comments Off on Iron deficiency anaemia

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