Sickle Cell Anaemia

Brief Information

Introduction

Sickle cell anaemia is the most common genetic (inherited) disease in England, affecting around 12,500 people.

Sickle cell anaemia affects the ability to carry oxygen around your body using your red blood cells. Normally, red blood cells carry oxygen from your lungs to the rest of your body. The cells are round and flexible, allowing them to easily move around your body.

However, in people with sickle cell anaemia, the shape and texture of the blood cells can change. They become hard and sticky and are shaped like sickles, or crescents. The cells die prematurely, leading to a shortage of red blood cells. This causes the symptoms of anaemia, such as tiredness and breathlessness.

If you have sickle cell anaemia, your blood cells can get stuck when moving through small blood vessels, stopping the supply of oxygen to parts of your body. This is known as a 'sickling crisis'. This can cause pain, tissue damage, and can lead to other serious complications, such as a stroke, or blindness.

The only cure for sickle cell anaemia is a bone marrow transplant. However, the procedure has many potentially serious side-effects and is not recommended for all cases.

The symptoms of sickle cell anaemia can be treated, and people with the condition can learn how to help prevent sickling crises from happening.

Causes

All blood cells contain a protein called haemoglobin. Haemoglobin is vital because it binds to the oxygen in our lungs, and transports it to the rest of your body.

Haemoglobin is created by a pair of genes - you inherit one gene from your mother and one from your father.

Thousands of years ago a mutation appeared in one of the genes. The mutated gene evolved in parts of the world where malaria was common, such as Africa, the Middle East and India. Due to patterns of migration, sickle cell anaemia is common among black Caribbean, black African, and black British communities. However, as these are inherited genetic diseases, it is impossible to automatically exclude anyone. Cases have been found in people who are of Portuguese, Spanish, French Corsican, Sardinian, Sicilian, Italian, Greek and Turkish descent.

People who inherit one of the mutated genes are known as having the sickle cell trait. Their bodies make both normal and sickle shaped blood cells. Usually, they have no obvious symptoms, unless they are in an environment where the oxygen levels are lower - such as on top of a mountain, or ballooning at high altitude.

If two people who have the sickle cell trait have a child, there is a chance that the child will inherit a pair of genes that both have the sickle cell trait. This means they are unable to make normal hemoglobin and have sickle cell anaemia. The chances of the sickle cell trait being passed on are outlined below.

• 25% chance that the baby will receive a pair of normal haemoglobin genes
• 50% chance that the baby will receive one normal gene and one mutated gene. In this case, they will not have sickle cell anaemia, but they will have the sickle cell trait
• 25% chance that the baby will receive a pair of mutated genes - they will have sickle cell anaemia

If one parent has the sickle cell trait, and the other parent has normal haemoglobin their baby will not get sickle cell anaemia. But, there is a 50% chance that the baby will receive the sickle cell trait.

Treatment

Living with Sickle Cell Anaemia

Most of the treatment for sickle cell anaemia involves preventing sickling crises and complications.

If you, or you child, is diagnosed with sickle cell anaemia, you will normally be referred to a specialised sickle cell clinic. A detailed plan of future medical care will be drawn up, and you will be provided with information and support to help you manage the condition.

It is important that you, or your child, attend all of your medical appointments, as regular checkups are required to monitor the level of red blood cells, and check for possible organ damage.

Pain management

The pain experienced during crises can very from mild to extremely painful. Mild pain can be treated using over-the-counter (OTC) medications, such as paracetamol. More severe pain may require stronger prescription painkillers and, in the most severe cases, injections of opiates, such as morphine.

Pain that lasts for a few days is known as acute pain. However, in some cases pain can last for up to six months, and continue after the other symptoms of the crisis have gone. This is known as chronic pain. This may require the long term use of painkillers.

Many people worry that long term use of painkillers, particularly strong opiate-based painkillers, such as morphine, will make them become addicted. Your specialist, or clinic, will carefully regulate the dosage you receive to minimise the chances of addiction. People with sickle cell anaemia are no more likely to become addicted to opiates than anyone else.

Children can become very upset and frightened during a painful crisis. However, using distractions, such as a favourite video game, or DVD, can help.

Some studies have shown that a type of therapy called Cognitive Behavioural Therapy (CBT) can help in the management of chronic pain.

CBT is based on the principle that the way we feel is partly dependent on the way we think about things. People who train themselves to react differently to their pain - using relaxation techniques, and maintaining a positive attitude - reported that the levels of pain experienced went down. They were also more likely to maintain a healthy lifestyle and diet, reducing the risks of further crises occurring.

Blood Transfusions

Blood transfusions increase the number of healthy red blood cells in your body. The procedure is used to help relieve the symptoms of anaemia.

Blood transfusions are sometimes used for children with sickle cell anaemia who have a high risk of stroke. The healthy red blood cells help the passage of oxygen to the brain, reducing the risk of a stroke.

As blood contains iron, regular blood transfusions can build up the level of iron in your blood which could cause damage to your organs. Therefore, if you are receiving regular transfusions, you will also need to have treatment to reduce your iron levels. This is normally achieved by using a medicine called desferrioxamine. This works by helping to remove the iron from your body through your urine and faeces.

Hydroxyurea

Hydroxyurea is a medicine that was first used in chemotherapy. It can be used by adults who have a high number of painful sickle crises. It appears to work by stimulating the production of foetal haemoglobin - a type of haemoglobin that is normally only found in new born babies. Foetal haemoglobin helps prevent the frequency of sickle cells.

Hydroxyuera does increase your risk of infections and can cause fatigue, so may not be suitable for everyone. Your clinic, or specialist, will be able to advise you it if is suitable for you.

Bone Marrow Transplantation

The only current cure for sickle cell anaemia is a bone marrow transplant. The procedure involves replacing the affected bone marrow with bone marrow donated from somebody who does not have sickle cell anaemia. Following a bone marrow transplant, the new bone marrow begins producing healthy blood cells.

There are some significant risks involved in having a bone marrow transplant. The new bone marrow can start producing cells that attack parts of your body. This is known as graft-versus-host disease (GVHD).

GVHD can affect many parts of your body, although the eyes, skin, stomach, and intestines are most commonly affected. Symptoms include rashes, nausea, weight-loss, irritation of the eyes, and jaundice.

Other risks that are related to bone marrow transplants include an increased chance of strokes, seizures and tumours.

Due to the associated risks, bone marrow transplants are normally only recommended in the following circumstances:

• If the patient is under 17 years of age, because children often have less organ damage from their sickle cell disease than adults, which improves their chances of survival
• If the patient has a brother, or sister, with healthy bone marrow, because a close family connection reduces the risks of developing GVHD
• If the patient has one, or more, serious complications caused by sickle cell anaemia, such as acute chest syndrome, which is a life-threatening condition where the airways of your lungs become blocked

More Information

• Sickle Cell Society
• NHS Sickle Cell & Thalassaemia Screening Programme
• Care and Management of Your Child with Sickle Cell Disease (PDF)

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