A 45-year-old man with aplastic anaemia requires regular blood transfusions, 2–4 units of blood every 4 weeks. He has now received over 100 units of blood.
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(a) What tests would you request to assess his degree of iron overload?
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Correct answer:
Tests for iron overload include:
(a) Serum iron and total iron binding capacity (TIBC). The normal percentage of saturation of the TIBC is 20–40%. In iron overload this may rise to 100% or even >100% if there is free non-transferrin bound iron in plasma.
(b) Serum ferritin – this is a measure of iron stores. Levels >1000 µg/L usually indicate severe iron overload.
(c) MRI scans can be used to detect iron overload in the liver and heart. Different MRI techniques are in use. T2* MRI is best for heart iron.
(d) Liver biopsy maybe used to get a histological and chemical measurement of liver iron and assess for cirrhosis. In a patient with aplastic anaemia, it maybe inadvisable because of a low platelet count predisposing to haemorrhage. It is also undertaken less often because MRI can measure liver iron.
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(b) What tests would you request to assess organ damage due to iron overload?
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Correct answer:
Tests for organ dysfunction include those for the heart, liver and endocrine glands.
For the heart: MRI, ECG, echocardiography and possibly 24-hour tape marker are used to assess heart rhythm and function.
For the liver: liver function tests, coagulation studies are needed. Ultrasound will help to determine whether liver cirrhosis has developed.
For the endocrine organs: tests for diabetes, testosterone level, thyroid and parathyroid function are needed.
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(c) What therapy is available for him?
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Correct answer:
Treatment of transfusional iron overload requires iron chelating drugs. Desferioxamine is given by subcutaneous infusion which may be difficult in a patient with aplastic anaemia (increased risk of haemorrhage or infection at the infusion site). Deferiprone is given by mouth. It is particularly effective at removing cardiac iron but carries a 1% risk of agranulocytosis. Deferasirox is also given by mouth and is currently the first choice for use in aplastic anaemia with iron overload.
