Sickle cell anaemia is a genetic (inherited) blood disorder where red blood cells develop abnormally.
Abnormal blood cells
Red blood cells carry oxygen from the lungs to the rest of the body. The cells are usually round and flexible, allowing them to move easily around the 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 (crescents). The cells die prematurely, leading to a shortage of red blood cells. This causes symptoms of anaemia, such as tiredness and breathlessness.
Sickle cell crisis
The sticky red blood cells can clog up blood vessels, resulting in nearby tissue becoming starved of oxygen. The lack of oxygen can trigger episodes of moderate to severe pain. These episodes are known as a sickle cell crisis.
The time a sickle cell crisis can last can be highly variable; anywhere from a few minutes to several months. Though on average, a crisis would usually be expected to last for around 5-7 days.
Serious complications
A lack of a regular oxygen supply can also result in tissue and organ damage. This can potentially lead to a wide range of complications, including:
- a stroke, where the blood supply to the brain is interrupted
- frequent and often serious infections because the spleen, which plays an important part in fighting infection, becomes damaged
- acute chest syndrome, a serious and sometimes life-threatening lung condition, which is thought to be triggered by infection
How common is sickle cell anaemia?
The genetic mutation (a change in the normal pattern of DNA, see Causes of sickle cell anaemia for more information) that is responsible for sickle cell anaemia first developed many hundreds or possibly thousands of years ago in Africa. For this reason, sickle cell anaemia is most common among black Caribbean, black African and black British people. The condition affects males and females equally.
Bone marrow transplants
A bone marrow transplant can sometimes be used to cure sickle cell anaemia. Bone marrow transplantation is usually only possible if the donation is provided by a brother or sister who does not have sickle cell anaemia and has the same bone marrow type. Only 1 person in 10 with sickle cell anaemia is able to find a suitable donor.
There are a number of alternative treatments that can help reduce the severity and frequency of the symptoms of sickle cell anaemia and prevent complications. For example, a medication called hydroxyurea has proved to be successful in treating moderate to severe sickle cell anaemia.
Outlook
The outlook for sickle cell anaemia can be highly changeable. Some people only have mild symptoms, while others have frequent attacks of pain and experience a wide range of complications.
There have been major advances in the treatment of sickle cell anaemia over the last twenty years. In the past, life-threatening complications, such as stroke or pneumonia (infection of the lungs) were common, and most people with the condition would die in childhood or early adulthood.
Nowadays, following improvements in preventative treatment, many of the complications associated with sickle cell anaemia can be avoided. The average life expectancy of a person with the condition is estimated to be 53-60 years of age. It is hoped that, in the future, the life expectancy of people with sickle cell anaemia will continue to increase as the effectiveness of treatments improves.
Glossary