iron deficiency anaemiaDefinition
Iron deficiency anaemia is a low red blood cell count or haemoglobin level caused by too little iron in the body.
What is going on in the body?
Though anaemia has many causes, iron deficiency is the most common. Inside red blood cells, there is a molecule called haemoglobin that carries oxygen to cells throughout the body. Iron is a very important part of haemoglobin and red blood cells. When the body does not have enough iron stored, too little haemoglobin is made to fill the red blood cells. The size and number of red blood cells decreases. This cuts down on the body's ability to carry oxygen to the tissues. As a result, symptoms may occur.
What are the signs and symptoms of the condition?
The signs and symptoms of anaemia usually develop over a long period of time and include:
Much less common signs of severe iron deficiency include:
- pale skin and eyes, called pallor
- thinning and flattening of the finger nails
- dizziness or light-headedness
- decreased ability to concentrate
- shortness of breath
- less endurance in exercise
- an abnormally fast heartbeat
- cravings for nonfood items such as ice, which is called "pica"
What are the causes and risks of the condition?
- a sore tongue or mouth
- a smooth, red tongue
This condition occurs when iron intake cannot keep pace with iron loss. This can be due to:
Women of childbearing age, pregnant women, children, and teens are at the greatest risk for this condition.
- low intake of iron in the diet.
- blood loss. This can be due to menstruation, the most common cause in younger women. It may also be due to blood loss from the gut, which may occur with stomach ulcers, bowel cancer, or other diseases of the gut. Frequent blood donations, bleeding or blood clotting problems, and other conditions are less common forms of blood loss.
- increased need for iron in the body. This can occur in pregnancy, when a baby growing in a woman's womb uses some of the woman's iron for its own growth. Rapid growth, which occurs in infancy, childhood and adolescence, also increases the body's iron needs.
- decreased ability to absorb iron from the diet. This can occur with conditions that affect the stomach or intestines. For example, people who have had part of the bowel removed with surgery or have bowel inflammation may have trouble absorbing iron into the body.
- other rare causes, such as taking certain medications that interfere with iron, such as antacids, or infections in the bowel.
What can be done to prevent the condition?
Taking certain measures can help prevent iron deficiency anaemia.
How is the condition diagnosed?
- Pregnant women and women who still have periods should eat an iron-rich diet and consider taking a multi-vitamin with iron.
- Children and adults should make sure to get enough iron in their diet.
- When possible, babies should be given breast milk, which contains iron. Iron-fortified formula should be used if breast feeding is not possible.
The history and physical examination often make a doctor suspect this condition. Blood tests can confirm the diagnosis and may show:
Other blood tests may also be done to help make the diagnosis in some cases. Further tests may be needed to determine the reason for the low iron if it is not clear. For example, screening tests for bowel cancer (such as a colonoscopy) or other blood loss from the bowels can detect blood in the stool.
- a decreased number of red blood cells
- abnormally pale and small red blood cells
- a decreased amount of haemoglobin
- a decreased level of iron in the blood
A bone marrow biopsy may need to be done in difficult cases. This is a procedure that involves inserting a special needle through the skin and into a bone, usually the hipbone. A sample of bone marrow is then taken with the needle. Bone marrow is a soft substance in the middle of some bones. Red blood cells are made and much of the body's iron is stored inside the bone marrow. A sample of bone marrow can be examined to look for iron deficiency. This is a very good method of detecting iron deficiency, though it is not usually needed.
What are the long-term effects of the condition?
Almost all problems caused by this condition can be reversed with treatment. However, if the anaemia is severe and other health problems exist, it can lead to: What are the risks to others?
The condition itself is not contagious.
What are the treatments for the condition?
The first step in treatment is to find and correct the reason for low iron stores. For example, the source of blood loss may need to be identified, especially malignancy needs to be excluded. Iron stores are then replaced. If a person does not have a problem absorbing iron, this can be done through diet and iron pills. Iron pills are the most common treatment for this condition.
Other helpful diet measures include avoiding large amounts of tea or coffee with meals, which may interfere with iron absorption. Food high in iron includes lean meat, fish, eggs, poultry, spinach, and iron-fortified cereals. People may be asked to get a serving of iron-rich food at each meal. Vitamin C pills or food rich in vitamin C may be helpful, because it helps the body absorb iron. Milk consumption of no more than three cups per day may also be advised, as excess calcium can reduce the absorption of iron.
Even when the body is healthy, it does not take in iron very well. Because of that, a person may be advised to take iron pills for several months to a year. Iron should be taken as prescribed by a doctor. If iron pills fail, which is fairly uncommon, iron can be given intravenously or through injections into a muscle.
What are the side effects of the treatments?
Iron is best absorbed on an empty stomach. On an empty stomach, iron pills may cause some bowel problems such as nausea, diarrhoea, heartburn, or constipation. Iron poisoning can occur with an overdose of iron pills. When iron is given intravenously or in a injection, a doctor will need to monitor the person closely. Taking iron this way can cause: What happens after treatment for the condition?
Most people's symptoms go away with treatment and they are "cured." In this setting, people can return to normal activities as soon as they desire. The exact treatment and when it may end often depends on the underlying cause as well. For example, some people have bowel cancer that has caused blood loss. This may require intensive treatment with surgery and chemotherapy.
How is the condition monitored?
After treatment is finished, blood tests are done to make sure iron stores have been replaced.
At this point, affected people simply need to monitor for a return of symptoms at home. Further monitoring may be needed depending on the cause of the low iron. Lifelong iron replacement is usually not necessary.
Author: Thomas Fisher, MD
Reviewer: eknowhow Medical Review Panel
Editor: Dr John Hearne
Last Updated: 21/09/2004
Potential conflict of interest information for reviewers available on request