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SICKLE CELL DISEASE

What is Sickle Cell Disease ?

Sickle cell disease is a disorder of the haemoglobin inside the red blood cells. Haemoglobin is the red pigment inside the red blood cells which carries oxygen from the lungs to the body tissues. Instead of normal haemoglobin, people with sickle cell disease have a type of haemoglobin called sickle haemoglobin. Under certain conditions, the sickle haemoglobin causes the red blood cells to alter shape. They change from their normal disc shape to a sickle shape. This is called sickling. It can occur with lack of fluids, infection, pregnancy and anaesthetics. Sometimes it happens for no obvious reason. The sickled red cells block up the small blood-vessels so that blood cannot get through. This can lead to pain in various parts of the body, often in the bones or the abdomen. This is called a sickle cell crisis. The sickle cells are more easily destroyed, leading to anaemia (lack of red blood cells). The severity and frequency of crises varies from one person to another. Some patients can lead a normal life, others may miss school or be absent from work quite often.

How does Sickle Cell Disease occur ?

Our haemoglobin type is inherited from our parents through a pair of genes, one from each parent. People who have sickle cell disease have inherited two abnormal genes, one from each parent. Instead of making normal haemoglobin (haemoglobin A), the red cells then make sickle haemoglobin (haemoglobin S). A person can also inherit one normal gene and one gene for sickle haemoglobin. In this case, their red cells make a mixture of sickle cell haemoglobin and normal haemoglobin A. This is called sickle cell trait. Sickle cell trait is not a disease. However, if both parents have sickle cell trait there is a one in four chance that any child will be born with sickle cell disease.

Why does Sickle Cell Disease occur ?

Sickle cell disease affects mainly people of African-Caribbean origin. It also occurs in people from Mediterranean, Asian and Arab countries. This is because in the past, before there was effective treatment for malaria, the presence of the sickle cell haemoglobin protected children against malaria : the malaria parasite does not like growing in red cells which contain sickle haemoglobin. They were therefore more likely to survive and have children than people with normal haemoglobin.

Treatment involved for Sickle Cell Disease

It is not possible to alter the type of haemoglobin within your red cells. Management therefore depends on trying to prevent painful crises and treating the symptoms if they occur. PREVENTION OF CRISES good nutrition and avoiding dehydration and exposure to cold all help prevent crises. Infections should be treated promptly. People with sickle cell disease are usually advised to take penicillin every day to prevent certain kinds of infection. (Erythromycin is used if allergic to penicillin.) This is especially important in children. Folic acid, a vitamin needed for blood formation, is usually prescribed, as people with sickle cell disease need more than usual: their red cell factory is working overtime to keep up with the breakdown of the sickle cells. Drug treatment with a drug called hydroxyurea is now sometimes used to prevent sickle crises from occurring. Regular blood tests are needed to check the response. TREATMENT OF CRISES This involves pain relief, warmth, fluids and rest, together with treatment of any infection. Mild crises can be treated at home but severe crises will mean that you need hospital treatment. This allows fluids, including more powerful painkilling drugs, to be given by drip. If the crisis is very severe, exchange transfusion may be performed. This means taking off some of your blood which contains the sickle cells and replacing it with normal blood.

After treatment for Sickle Cell Disease

In between crises you need to pay attention to things like avoiding getting short of fluids and getting cold. It is important to take folic acid and penicillin regularly. If a painful crisis starts, you should take some painkillers, go to bed, keep warm, and drink plenty. If there is a fever or cough, or if the symptoms do not start to improve within a few hours, the doctor should be called. He will decide whether the condition should be treated in hospital. If receiving hospital treatment, the most important thing to watch for is whether the pain is improving or not. This helps the doctors decide whether additional treatment like exchange transfusion is needed.

If Sickle Cell Disease is left untreated

If sickle cell crises are not treated adequately, then a vicious circle develops. The sickling process itself leads to further sickling. This is especially true when the lungs are involved. Oxygen cannot then be taken into the body properly. This low level of oxygen in the body then leads to further sickling. Life expectancy is reduced to some extent, even with treatment: without treatment the condition can be fatal at quite a young age.

Effects on the family of Sickle Cell Disease

Sickle cell disease is an inherited condition, so other members of your family may have sickle cell disease or sickle cell trait. The doctor will probably suggest that everyone is tested so that they know whether they have either sickle cell disease, sickle cell trait, or normal haemoglobin. Many large cities in Great Britain have sickle cell centres. Here anyone who wishes can find out more about the disease and have a blood test. Counselling is available for couples who both have sickle cell trait. A lot of support will be needed from members of the family.