Iron Deficiency Anaemia

Understanding blood

Blood is made up of a fluid called plasma which contains:

• Red blood cells - which take oxygen around the body.
• White blood cells - which are part of the immune system and defend the body from infection.
• Platelets - which help the blood to clot if we cut ourselves.
• Proteins - and other chemicals that have various functions.

Red blood cells are made in the bone marrow, and millions are released into the bloodstream each day. A constant new supply of red blood cells is needed to replace old cells that break down. Red blood cells contain a chemical called haemoglobin. Haemoglobin binds to oxygen and takes oxygen from the lungs to all parts of the body.

To constantly make red blood cells and haemoglobin you need a healthy bone marrow and nutrients such as iron and certain vitamins which we get from food.

What is iron deficiency anaemia?

Anaemia means:

• You have fewer red blood cells than normal, OR
• You have less haemoglobin than normal in each red blood cell.

In either case, a reduced amount of oxygen is carried around in the bloodstream. The most common cause of anaemia in the UK is a lack of iron. Iron is needed to make haemoglobin. Anaemia caused by a lack of iron is called iron deficiency anaemia.

What are the causes of iron deficiency anaemia?

A normal balanced diet will usually contain enough iron for the body's needs. A low level of body iron leading to anaemia can result from various causes. Some are more serious than others, and include the following:

Heavy menstrual periods

Anaemia is common in women of all ages who have heavy periods. About 1 in 10 women will become anaemic at some stage due to heavy periods. The amount of iron that you eat may not be enough to replace the iron that you lose with the blood each period. Having heavy periods does not always lead to anaemia. Anaemia is more likely to develop if you have heavy periods and eat a diet that contains little iron.

Pregnancy

A growing baby needs iron and will take it from the mother. Anaemia is common in pregnant women. It is more likely to develop during pregnancy if you eat a diet that has little iron.

Poor absorption of iron

Some conditions of the gut (intestine) lead to poor absorption of various foods, including iron. Coeliac disease is an example.

Bleeding from the gut (intestine)

Several conditions of the gut can lead to 'internal bleeding'. Sometimes this is sudden, for example, after a burst duodenal ulcer. Vomiting or passing blood is then obvious.

However, often the bleeding is not obvious. A constant trickle of blood into the gut can be passed unnoticed in the stools (faeces). The iron that you may lose with the bleeding may be more than you eat. Conditions causing this include: stomach or duodenal ulcers, colitis (inflammation of the large intestine), inflammation of the oesophagus (gullet), piles (haemorrhoids), cancers of the bowel, and other rare bowel disorders. If you have one of these problems, you may have other gut symptoms such as stomach pains, constipation, or diarrhoea. However, in the early stages of these conditions, you may not have any symptoms, and anaemia may be the first thing that is noticed. For example, iron deficiency anaemia in an older person is a common first indication that bowel cancer has developed.

Medication

Some medicines which you may take for other conditions can sometimes cause bleeding into the gut without causing symptoms. The most common example is aspirin. Other anti-inflammatory painkillers such as ibuprofen, naproxen, diclofenac, etc, also have this side-effect in some people. (The reason anti-inflammatories may cause bleeding is because they sometimes irritate the stomach lining which can lead to bleeding.)

Bleeding from the kidney

A small but regular trickle of blood from diseases of the kidney or bladder may not be noticed in the urine. However, enough may be lost to cause anaemia.

Dietary factors

Not eating foods with enough iron is sometimes the cause of iron deficiency anaemia. This is uncommon in the UK as iron is in meat, liver, green vegetables, flour, eggs, and other foods. However, some people who may have a poor diet with 'just enough' iron to get by normally may slip into anaemia if other factors develop. For example, a barely adequate diet combined with a growth spurt in children, with pregnancy, or with heavy periods may lead to anaemia.

A restricted diet such as a vegan or a limited vegetarian diet sometimes does not contain enough iron.

Traditional diets in some parts of the world contain a high level of chemicals such as phytates and polyphenols. For example, certain types of unleavened breads (such as chapatis) may contain a high level or phytates, and tea can contain a high level of polyphenols. These chemicals interfere with the way iron is absorbed from the gut. So, if you eat a lot of these foods, it can lead to iron deficiency. For example, in parts of India where chapatis are a staple food, iron deficiency anaemia is common.

Hookworm infection

This gut infection is the most common cause of iron deficiency anaemia world-wide. It affects people living in, and visiting, certain tropical countries. The worm feeds off blood inside the gut.

What are the symptoms of iron deficiency anaemia?

• Common symptoms are due to the reduced amount of oxygen in the body. These include: tiredness, lethargy, feeling faint, becoming easily breathless.
• Less common symptoms include: headaches, palpitations, altered taste, sore mouth, and ringing in the ears (tinnitus).
• You may look pale.
• Various other symptoms may develop, depending on the underlying cause of the anaemia (see below).

Possible complications

Complications may develop if the anaemia becomes severe and is not treated. For example, you can develop: fragile and broken nails, heart failure, and hair loss. You may also be more prone to develop infections as a lack of iron can affect the immune system.

Anaemia in pregnancy increases the risk of complications in both mother and baby. For example, there is an increased risk of: having a low birthweight baby, preterm (premature) delivery, postnatal depression, and low iron reserves in the baby which may possibly lead to anaemia in the newborn baby.

How is iron deficiency anaemia diagnosed?

A blood test can confirm that you are anaemic. A test called the full blood count (FBC) is the main test. For this test the blood sample is put into a machine which automatically:

• Counts the number of red cells, white cells, and platelets per ml of blood.
• Measures the size of the red blood cells and calculates their average (mean) size.
• Calculates the proportion of blood made up from red blood cells (the haematocrit).
• Measures the amount of haemoglobin in the red blood cells.

This test can determine if you are anaemic, and often gives a good idea as to the cause of anaemia. But, as there are many different causes of anaemia, there may be some doubt as to the cause of the anaemia.

Therefore, you may need another blood test to confirm that the cause of the anaemia is due to lack of iron. A blood test that measures a protein called ferritin may be done. The level of this protein usually reflects the total body iron stores. A low level usually indicates that you have a lack of iron. (However, the test is sometimes difficult to interpret if infection or inflammation is present, as levels of ferritin can be high even in the presence of iron deficiency.)

Do I need any further tests?

It is important to find the cause of the iron deficiency. The cause may be obvious in some people. For example, anaemia is common in pregnancy, and in women with heavy periods. In these situations, if you are otherwise well and have no other symptoms, then no further tests may be needed. However, further tests may be advised if the cause is not clear. Every case is different and your doctor will assess if you should have further tests.

Tests that may be advised include one or more of the following:

• Tests to look into the gut to see if there is any internal bleeding. These may be advised even if you do not have gut symptoms, especially in older people. The tests may include looking into the stomach with a special telescope (endoscopy). Checking the rectum and bowel may also be advised. This is commonly done by using a special telescope (sigmoidoscopy or colonoscopy). It is sometimes done with a special X-ray examination (barium enema).
• A biopsy (small sample) of the lining of the gut may be taken if coeliac disease is suspected as the cause.
• If you have recently been to the tropics, a stool sample (sample of faeces) may be checked to rule out hookworm.
• Other tests may be advised if the cause is still unclear.

What is the treatment for iron deficiency anaemia?

Iron tablets are usually prescribed to correct the anaemia. Other treatments may also be advised, depending on the underlying cause.

Iron tablets

Various iron tablets and liquid medicines are available. A doctor will advise on one. The length of course will vary depending on how bad the anaemia is. A blood test after a few weeks will show if the treatment is working. Once the blood level is back to normal, you should continue to take iron for at least three further months. This will ensure that reserves of iron are built up in your body.

Side-effects from taking iron occur in some people. These include: feeling sick (nausea), an upset stomach, constipation, or diarrhoea. Tell a doctor if side-effects are a problem. Don't stop the iron, as the anaemia will not get better. Possible ways that a doctor may suggest to reduce the problem with side-effects are:

• Take the iron tablets with meals. Food reduces the absorption of the iron and so you may need to take a longer course to correct the anaemia.
• Take a lower dose, but again a longer course will be needed to correct the anaemia.
• Drink plenty of fluids if constipation develops.

Iron tablets may make your stools (faeces) black. This is normal and nothing to worry about. However, it is sometimes confused with blood in the stools from internal bleeding which can also make your stools black.

REMEMBER to keep iron tablets away from children. An overdose of iron tablets can be very dangerous in children (who may think that they are sweets).