Anaemia

What is anaemia?

Anaemia is a condition in which the amount of haemoglobin in the blood or the number of red blood cells is reduced to below normal levels. Haemoglobin is an iron-containing pigment found in red blood cells, which aids the transport of oxygen from the lungs to the body tissues. This means that if you are anaemic your body is less able to transport oxygen.

Iron deficiency anaemia is caused by a lack of iron while pernicious anaemia is caused by faulty absorption of vitamin B12. Iron deficiency anaemia is the most common type and occurs most often in women between the ages of 15 and 44 years and in both men and women over the age of 75 years. Symptoms of pernicious anaemia are usually not seen until after the age of 30 with the average age at diagnosis being around 60. Pregnant women, children, premature infants and vegetarians are all at an increased risk of becoming anaemic (see below).

What are the symptoms of anaemia?

Anaemia can cause symptoms of tiredness, lethargy, breathlessness on exertion, dizziness, palpitations and headache. Your doctor may examine your eyelids, which can lose their normal colour, and your lips, tongue or skin, which may look pale. Some people will not have any symptoms.

What causes anaemia?

The most common cause of iron deficiency anaemia is blood loss. The blood loss may be gradual, such as in a woman having heavy periods, or sudden, as a result of severe bleeding (eg, in a patient with a perforated stomach ulcer or during childbirth).

Anaemia may also be caused by your red blood cells being broken down too quickly. This can happen in conditions such as sickle-cell anaemia, malaria or kidney failure.

Your body may be unable to produce enough red blood cells if your diet does not contain enough iron, vitamin B12 or folic acid. Pregnant women, children and premature infants all need a lot of iron and may need to take an iron supplement. It is also more difficult for the body to absorb iron from vegetables than from meat so vegetarians need to ensure that they have sufficient quantities of iron in their diet.

Another cause of pernicious anaemia is a lack of intrinsic factor, a protein that occurs naturally in the body. It is secreted by glands in the stomach and is necessary for the absorption of vitamin B12. Lack of intrinsic factor can occur in people who have had previous stomach surgery. The reason for the condition is unknown but it could be genetic.

Are there any tests necessary?

A blood test will show if you are anaemic and may also indicate the reason for the anaemia. Your doctor will ask for a medical history to determine any likely cause or combination of factors that may have caused you to become anaemic. If it is thought that you may have pernicious anaemia, your doctor will carry out a Schilling's test to check for vitamin B12 absorption. If you need to have this test your doctor will explain it to you. 

What treatment is available?

Treatment will depend on the type and cause of the anaemia. For iron deficiency anaemia, iron tablets will be given for a period of months, initially to correct the deficiency and then to replenish the body's stores. Sometimes the tablets can cause side effects such as constipation or diarrhoea; they can also darken stools. If oral supplements are not sufficient or if iron stores need to be replenished rapidly, an iron injection may be given.

If there is a lack of the intrinsic factor necessary for B12 absorption, vitamin B12 injections (hydroxocobalamin) will be given every three months. Alternatively, cyanocobalamin, another form of vitamin B12, can be taken orally. Vitamin B12 is given for life as the intrinsic factor cannot be restored.

If the anaemia has been caused by another illness, this will be treated directly.

Self-help measures:

  • If the anaemia is due to a deficiency in your diet you must try to increase your intake of that element:
      - Vitamin B12 is found in meat, fish, eggs and milk.
      - Iron is found in liver, meat, green vegetables, flour, eggs and milk.
      - Folic acid (another B vitamin vital to the formation of red blood cells) is found in green
        vegetables (lightly cooked) especially broccoli and spinach, and in liver and kidney.
  • Take your iron tablets with orange juice to aid absorption.
  • Keep your iron tablets away from children, iron tablets can be fatal to children and often look similar to sweets.
  • If you are vegetarian, try to find other sources of vitamin B12 such as eggs and milk; some breakfast cereals have added B12 while soya milk and yeast extracts are also a good alternative to supplements.

Fact sheet provided by MIMS

Date last reviewed: June 2014

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