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Introduction Anaemia is the general name for a range of disorders affecting red blood cells. Red blood cells contain haemoglobin, which is responsible for carrying oxygen in the blood. To produce red blood cells, the body needs iron, vitamin B12 and folic acid. If one or more of these is deficient, anaemia will develop. Red blood cells are produced in the bone marrow and circulate in the bloodstream before they are broken down in the spleen. If the level of red cells (and therefore of haemoglobin), in the blood is abnormally low the oxygen-carrying capacity of blood is reduced and anaemia develops. Haemoglobin is measured in terms of the weight present in grams (g) per 100 millilitres (1 decilitre or dl) of blood. A normal level in females will lie somewhere between 11.5 and 15.5 g per dl, and in males between 13 and 18 g per dl. The normal range of red cell numbers per cubic millimetre of blood is 4,100,0005,200,000 in females and 4,400,0005,800,000 in males. Iron deficiency anaemia is the most common type of anaemia. It affects up to 30% of the worlds population. Up to 14% of menstruating women in developed countries have iron deficiency anaemia. Megaloblastic anaemia (the red cells are megablastic i.e. large and abnormal) develops if vitamin B12 or folic acid are lacking. A lack of folic acid, leads to megaloblastic anaemia. Another type of megablastic anaemia is called pernicious anaemia, in which there is insufficient absorption of vitamin B12 from the diet. Haemolytic anaemia occurs as the result of an inherited or an acquired condition in which the body destroys red blood cells prematurely. Haemolysis describes the breaking up of red blood cells, resulting in the release of haemoglobin into the plasma. Aplastic anaemia results from the failure of the bone marrow to produce sufficient numbers of red blood cells.
Symptoms General symptoms of anaemia include: tiredness, breathlessness, palpitations, dizziness, and headache. If the anaemia is severe, chest pain, and leg pains can occur. Long-term effects of iron deficiency: sore tongue (glossitis), pinful cracks at the corners of the mouth (cheilosis), brittle, flaking nails, spoon-shaped nails, unusual dietary cravings (pica), difficulty in swallowing (dysphagia), pallor (pale skin), and loss of weight. Pernicious anaemia also causes soreness of the tongue, loss of weight, skin pallor often with a lemon tint, and intermittent diarrhoea. In untreated cases the nervous system may be affected, causing tingling of the fingers and toes, muscle weakness, pains in the legs and difficulty walking, depression and confusion. Megablastic anaemia due to folic acid deficiency also causes soreness of the tongue, indigestion and diarrhoea. Haemolytic anaemia also causes pale skin, often with a yellowish tinge. The spleen will be enlarged, due to ruptured red cells. Aplastic anaemia also causes fever, sore throat, bruising and bleeding and blood spots, pale skin and signs of heart failure.
Causes Each type of anemia has different causes: Iron-deficiency anaemia is caused by a shortage of iron. It affects women much more often than men, because women lose some blood in each menstrual period between puberty and the menopause. An average healthy mixed diet will contain enough iron to make up normal menstrual losses, but unusually heavy periods, a poor diet, or large loses of weight can lead to a shortage of iron. In some cases there is also blood loss from elsewhere, especially from the stomach/ intestine. This may be from stomach and duodenal ulcers or from piles. Bleeding high up in the intestine turns the stools black. Bleeding piles produce visible red blood. Chronic diseases, such as infections, cancer and rheumatoid arthritis, can cause iron-deficiency anaemia because the developing red cells in the bone marrow are unable to use the iron reserves. Haemolytic anaemia occurs when red blood cell destruction is increased as the result of an acquired or inherited condition, which generally interferes with normal red blood cell production. They include hereditary Spherocytosis, Sickle cell anaemia, and Thalassaemia. Megaloblastic anaemia develops if vitamin B12 or folic acid are lacking and is mainly caused by a diet low in fresh fruit and vegetables. Reduced absorption of folic acid may be due to excessive alcohol consumption and by some medicines. There is an increased need for folic acid during pregnancy. Folic acid deficiency also occurs in people with cancer and in those with coeliac disease. Pernicious anaemia is caused by a shortage of vitamin B12. This is usually because the vitamin is not being absorbed, because the stomach lining does not produce a certain chemical (intrinsic factor). The bone marrow needs vitamin B12 in order to produce red blood cells. In pernicious anaemia the blood contains a smaller number of abnormally large cells (megablastic), which do not last as long as normal. In Aplastic anaemia, the bone marrow does not make any new red cells, nor indeed any other kind of blood cells, and so the immune system cant work properly. The average life of a red cell is 120 days, so new cells have to be made all the time. If this does not happen, the anaemia will get steadily worse and create a very serious situation. About a third of all cases of aplastic anaemia follow virus infections, especially measles, mumps and hepatitis, or are caused by drugs such as butazolidine, sulphonamides, chloramphenicol by mouth or dipyrone. Because of this risk, most of these drugs are no longer prescribed. Inhaling benzene fumes can also cause aplastic anaemia. In most cases, however, the cause remains obscure. The condition is rare, affecting only 2 to 5 people per million
Anaemia and pregnancy Iron-deficiency anaemia and megaloblastic anaemia can occur during pregnancy. A woman needs up to twice as much iron as usual during pregnancy (normally 30 mgs a day). Iron is needed to produce more blood to supply the baby with the necessary nutrients and oxygen. Up to half of all pregnant women require an iron supplement from the 20th week of pregnancy. Lack of folic acid can make a pregnant woman anaemic. Folic acid is needed for the development of the babys spinal cord and general growth. The Department of Health recommends that women should take a daily supplement of 0.4mg of folic acid while they are trying to become pregnant, and for the first twelve weeks of pregnancy. Folic acid tablets can be obtained from pharmacies, large supermarkets, health food stores and by prescription. Take the 5-a-day fruit and veg test Diagnosis The diagnosis of iron deficiency anaemia is made on the basis of a blood test. Someone with this condition has a smaller than usual number of red cells in a given volume of blood. The cells are smaller, too, and contain less than the normal amount of haemoglobin.
Diagnosis may be more difficult when more than one type of anaemia is present. It may be necessary to carry out a wider range of investigations to detect reduced levels of vitamin B12 and folic acid. The levels of iron in the serum (derived from the blood taken for testing) can be measured, and in rare cases a sample of blood-forming bone marrow may be taken for examination.
Treatment Iron deficiency anaemia is managed by treating the underlying cause and replacing the iron that is missing from the body. Taking iron tablets is the usual way of building up normal levels of iron again and should be taken until the blood level is back to normal and then for a further three months to build up the iron stores. A different iron preparation or a lower dose (taken for longer) may be an option if the standard treatment produces side effects such as an upset stomach, constipation or diarrhoea. Stools may be black when iron is taken. Tests may be advised if the cause of the anaemia is not clear. The adverse effects of iron tablets are mainly nausea, abdominal pain, diarrhoea or constipation. These are directly related to the amount of iron in the intestine. Another full blood test may be done two weeks after treatment has started, in order to assess treatment response. The haemoglobin level should rise by about 0.1g to 0.2g per decilitre per day (about 2g per decilitre every three weeks). Iron replacement will normally be continued for three months once the haemoglobin has returned to normal, in order to replenish iron stores in the body. Failure to respond to treatment usually means that tablets are not being taken properly. However, it can be due to continuing excessive blood loss, failure to absorb the iron, an inflammatory disease, or another cause of anaemia. If iron taken by mouth cannot be tolerated, or if more iron is being lost than can be absorbed by mouth, then providing iron by injection or through a vein may be considered. The treatment of pernicious anaemia is also highly effective. A form of vitamin B12 known as hydroxocobalamin is given twice in the first week and then weekly until the blood is normal. In very severe cases a blood transfusion may be needed. Once normal a dose of vitamin B12 needs to be taken every three months for life. Haemolytic anaemia may be treated by removing the spleen where most of the red cell destruction occurs. This is usually very effective. Aplastic anaemia may be more difficult to treat. Because all the cells produced in the bone marrow are affected, no immune system cells are produced, putting the individual at considerable risk of contracting infections. Bleeding may be a problem because of the absence of bone marrow products called platelets that are needed for blood clotting. Without treatment the condition can lead to death. In the presence of a matched donor and young people with severe or very severe aplastic anaemia, a bone marrow transplant is usually the treatment of choice. People without a donor are usually given immunosuppressive therapy (IS) as first line treatment, and require regular blood transfusions during (and before) pregnancy. If possible, it is recommended that women take folic acid supplements for three months before they become pregnant. In cases of unplanned pregnancy it is recommended that women start taking folic acid as soon as they know they are pregnant for at least the first 12 weeks of pregnancy. The recommended dose is 400 micrograms daily a day. Folic acid can be found in green leafy vegetables, root vegetables, mushrooms, fruit, nuts and pulses. Iron tablets are recommended for pregnant women who may not be getting enough iron from their diet. The normal recommended daily dose for a pregnant woman is 30mg. Around the 20th week is when the most iron will be needed, as this is when the most extra blood production happens. Iron can be found in leafy green vegetables (e.g. broccoli, spinach, kale), lean red meat (e.g. pork, lamb or beef),strawberries and fibre-rich or wholemeal foods. Vitamin C helps the body absorb iron, this can be found in orange or cranberry juice or taken as a supplements. Tea and coffee affect the bodys absorption of iron and should be reduced or eliminated from the diet.
References Diagnosing anaemia. Bandolier 1997, issue 45, pages 6-7. http://www.jr2.ox.ac.uk/bandolier/band45/b45-6.html Department of Health Referral Guidelines for Suspected Cancer. (2000) Chapter 2, Upper Gastrointestinal Cancers. Chapter 3, Lower Gastrointestinal Cancers. Iron deficiency anaemia. Frewin R et al. British Medical Journal 1997, volume 314, pages 360-363. Synchronous upper and lower gastrointestinal endoscopy is an effective method of investigating iron-deficiency anaemia. Hardwick RH, Armstrong CP. British Journal of Surgery 1997, volume 84, pages 1725-1728. Treatments for iron deficiency anaemia in pregnancy. (Cochrane Review). Cuervo LG, Mahomed K. The Cochrane Library, 4, 2001. http://www.update-software.com/abstracts/ab003094.htm Oral contraceptive pills for heavy menstrual bleeding (Cochrane Review). Iyer V et al. The Cochrane Library, 4, 2001. http://www.update-software.com/abstracts/ab000154.htm
Glossary Blood Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Heart The heart is a muscular organ that pumps blood around the body.
Stomach The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.
Immune system The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.
Oxygen Oxygen is an odourless, colourless gas that makes up about 20% of the air we breathe.
Bone marrow Bone marrow is the soft, spongy tissue in the centre of bones that produces blood cells.
Vein Veins are blood vessels that carry blood from the rest of the body back to the heart.
Plasma Plasma is the liquid part of blood, which holds other blood cells together.
Red cell Red blood cells transport oxygen around the body and remove carbon dioxide.
Platelet Platelets are cells in the blood that control bleeding by plugging the broken blood vessel and helping the blood to clot.
Chronic Chronic usually means a condition that continues for a long time or keeps coming back.
Donor A donor is a person (living or dead) who donates blood, an organ or other body parts to another person in need.
Deficiency If you have a deficiency it means you are lacking in a particular substance needed by the body.
Stool Stool (also known as faeces) is the solid waste matter that is passed from the body as a bowel movement.
Heartburn Heartburn, also known as indigestion, is a painful, burning discomfort felt in the chest, usually after eating.
High temperature A high temperature, also known as a fever, is when someone's body temperature goes above the normal 37C (98.6F).
Palpitations Palpitations refer to an irregular heartbeat, or the sensation of skipped or extra heartbeats.
Craving A craving is a powerful, often uncontrollable urge for a particular thing.
Pain Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
Depression Depression is when you have feelings of extreme sadness, despair or inadequacy that last for a long time.
Ulcer An ulcer is a sore break in the skin, or on the inside lining of the body.
Diarrhoea Diarrhoea is the passing of frequent watery stools when you go to the toilet.
Nausea Nausea is when you feel like you are going to be sick.
Constipation Constipation is when you pass stools less often than usual, or when you are having difficulty going to the toilet because your stools are hard and small.
Rupture A rupture is a break or tear in an organ or tissue.
Dose Dose is a measured quantity of a medicine to be taken at any one time, such as a specified amount of medication
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