Anaemia is one of the most common blood disorders and is generally defined as the deficiency of haemoglobin in blood. Anaemia can be of the following types:
- Deficiency anaemias either due to inadequate intake of iron, vitB12, or inadequate production of normal red blood cells by the bone marrow as in iron deficiency anaemia, megaloblastic anaemia, pernicious anaemia, aplastic anaemia, etc.
- Anaemia due to increased destruction of red blood cells, as in various haemolytic diseases and in thalassaemia.
- Anaemia due to sudden blood loss, as in an accident, or blood loss of a more chronic nature as in some bleeding disorders.
Symptoms of Anaemia
The most common symptoms of anaemia are easy fatigability, breathlessness, headache, palpitations and dizziness. Pallor of the skin, mucous membranes and conjunctiva of the eyes are often seen.
Iron Deficiency Anemia
This is by far the commonest type of anaemia found in most parts of the world, especially in the developing countries. The most common causes of iron deficiency anaemia are:
- Inadequate dietary intake of iron
- Bleeding, resulting in increased loss of iron
- Deficiency in absorption of dietary iron from the intestine, known as malabsorption
Inadequate dietary intake of iron
- A child in whom weaning is delayed or not proper can develop iron deficiency anaemia as milk is a very poor source of iron.
- In adolescents there occurs a sudden increase in the iron requirement due to growth spurt, and this may lead to imbalance between dietary intake and requirement of iron, causing iron deficiency anaemia.
Bleeding, resulting in increased loss of iron
- There is a cyclic loss of blood in women during menstruation. A pregnant mother also requires additional iron for the growing fetus and for herself. These factors result in iron deficiency anaemia being more common in women than men during their reproductive years.
- In the middle-aged and elderly, iron deficiency anaemia can be as a result of various bleeding disorders of the gastro-intestinal system like gastric ulcers, hookworm infestation, etc.
- Many drugs are also known to cause gastro-intestinal bleeding when taken over a long period of time – the most commonly used group being the anti-iflammatory drugs, prescribed for chronic joint pains.
Apart from these common causes, there are some disorders known as malabsorption disorders which prevent adequate absorption of iron from the intestine, causing iron deficiency anaemia.
Vitamin B12 Deficiency anaemia
Vitamin B12 is required for the maturation of red blood cells. It is absorbed in the body from the lower ileum. This absorption is facilitated by an enzyme known as ‘intrinsic factor’, secreted by the stomach. Animal foodstuffs are the main sources of dietary Vitamin B12.
Deficiency of Vitamin B12 in the body can be either due to inadequate dietary intake or impaired absorption from the ileum because of insufficient ‘intrinsic factor’.
Vitamin B12 deficiency can lead to a condition known as megaloblastic anaemia where most of the red blood cells fail to mature. These immature red blood cells are called megaloblasts and are destroyed easily.
Deficiency of ‘intrinsic factor’ is due to an auto-immune disease where the enzyme secreting cells of the stomach are destroyed. Megaloblastic anaemia primarily due to deficiency of intrinsic factor in the stomach is known as pernicious anaemia.
Folate Deficiency Anaemia
Like Vitamin B12, folate is also essential for the maturation of red blood cells. It is present in both vegetables and animal foodstuffs. Much is destroyed by cooking. Deficiency of folate can be as a result of:
- Dietary insufficiency of meat and vegetables
- Increased requirement such as in pregnancy, leukaemia, haemolytic anaemia
- Impaired absorption from the intestine in diseases like sprue
Folate deficiency also causes megaloblastic anaaemia.
Diagnosis of Anaemia
Examination of the blood and peripheral blood film is usually adequate to establish the diagnosis of anaemia and usually involves the following tests:
- Haemoglobin level estimation
- Total Red blood cell count
- Reticulocyte count
In addition, examination of the stool for occult blood, urine, bone marrow as well as other special investigations may sometimes be required.
Treatment of Anaemia
Iron deficiency anaemia is commonly treated with oral iron supplements in the form of ferrous sulphate tablets. These tablets contain 200mg of the salt and 60mg of elemental iron, to be taken thrice daily. They can cause dyspepsia, constipation or diarrhoea in a small proportion of patients. Some patients may require injections in the form of iron-sorbitol or iron-dextran.
Folate deficiency anaemia is commonly treated with oral supplements of folic acid tablets containing 5mg of folic acid, to be taken once daily.
Vitamin B12 deficiency has to be treated parenterally in the form of hydroxocobalamin injections administered in a dosage of 1000 micrograms twice during the first week, followed by a weekly dose of 1000 micrograms for a further six weeks .
Blood transfusion may sometimes be required.
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