VOL: 99, ISSUE: 04, PAGE NO: 30
Anaemia is a condition in which the blood has an abnormally low oxygen-carrying capacity.
There are three general causes of anaemia:
1. Insufficient red blood cells
- Haemorrhagic anaemia results from blood loss, either acute (stab wound) or chronic (bleeding ulcer);
- In haemolytic anaemia red blood cells are ruptured prematurely;
- Aplastic anaemia results from the destruction or inhibition of the blood cell producing components in the red bone marrow by certain toxins, drugs, or ionising radiation.
2. Decreased haemoglobin content:
- Nutritional anaemia is suspected when haemoglobin (Hb) molecules are normal, but erythrocytes contain fewer than usual Hb molecules;
- Iron deficiency anaemia is usually a result of haemorrhagic anaemias, but also results from inadequate intake of iron-containing foods or impaired iron absorption;
- Pernicious anaemia is due to a deficiency of vitamin B12.
3. Abnormal haemoglobin:
Production of abnormal Hb is normally genetically based, such as thalassaemia and sickle cell anaemia.
Causes of iron deficiency anaemia
- Heavy menstrual periods.
- Poor absorption of iron.
- Intestinal bleeding.
- Some medicines such as aspirin, ibuprofen, naproxen, and diclofenac.
- Bleeding from the kidneys.
- Poor diet.
- Hookworm infection.
Signs and symptoms
- General tiredness or weakness.
- Loss of breath on exertion.
- Dizziness and/or fainting.
- Pale face.
- Pulling down the lower eyelid can indicate anaemia if the colour is pale.
- Sore mouth or tongue (may mean deficiencies in vitamin B group).
- Medical history.
- Physical examination.
- Full blood count and iron studies.
- Iron deficiency anaemia is characterised by low ferritin, low serum iron, raised total iron-binding capacity, low Hb and low mean corpuscular volume (MCV).
- Gastrointestinal (GI) investigations should be considered in all patients with confirmed iron deficiency, unless there is a history of significant non-GI blood loss.
- Treatment of an underlying cause should prevent further iron loss.
- All patients should have iron supplementation to correct anaemia and to replenish body stores: 200mg of ferrous sulphate three times daily, although ferrous gluconate or ferrous fumarate are as effective.
- Continue supplementation for three months after correction of anaemia to replenish iron stores.
- Once normal, the Hb concentration and red cell indices should be monitored on a three-monthly basis for one year and again after a further year. Further investigation is only necessary if the Hb and MCV cannot be maintained in this way.
- Education regarding the nature of the condition.
- The elements of a good diet, with advice on foods containing iron.
- The dose, route, duration and side effects of ferrous sulphate.
- Details of further investigations, date and times.
- All symptoms should be reported.
There is research into the importance of stratifying for the risk of significant disease according to Hb level and the value of computerised tomography colonography in investigating iron deficiency anaemia.
McGee, M. (2000) A guide to laboratory investigations. Abingdon: Radcliffe Press.