Sickle Cell Anaemia
Sickle Cell Anaemia is a disease that affects the haemoglobin in the red blood cells. The haemoglobin is what the oxygen binds to so changing this means less oxygen is carried around the body. The blood cells also change shape in a sickle shape and become fragile which means that they can break up and clog up blood vessels which leads to blood clots. These episodes are called crises’. Crisies’ can cause many problems such as strokes and heart attacks. Sickle Cell Anaemia can also cause acute chest syndrome a life-threatening infection in the lungs which can cause problems with the air circulating in the lungs.
All of these conditions need urgent medical attention due to the severe risk they cause to a person’s health. The most common treatment for Sickle Cell Anaemia is with the drug hydroxycarbamide, also known as hydroxyurea. The drug, which is given if a person has recurring episodes of a sickle cell crisis which require treatment in hospital, was found to stimulate the production of a type of haemoglobin called foetal haemoglobin. Foetal haemoglobin (HbF) is found in unborn babies and is gradually replaced by adult haemoglobin as the child gets older.
As foetal haemoglobin is not affected by the sickle cell mutation, it is able to partly take over the role of adult haemoglobin, helping to reduce the risk of someone with the condition experiencing a sickle cell crisis. Replacing the affected adult haemoglobin with foetal haemoglobin by treatment with Hyrdoxyurea which stimulates production of HbF means that blood cells are able to carry more oxygen around the body. Having fewer red blood cells that are affected by Sickle Cell Anaemia also means that they won’t become fragile so blood clots are less likely.
This reduces the threat of Crisies’ to an affected person. Red blood cells are the body’s principal means of transporting oxygen around the body. Sickle cell anaemia is a genetic blood disorder where red blood cells develop abnormally. These cells are rich in iron containing haemoglobin which bind to oxygen and are responsible for the blood’s red colour. In humans, red blood cells are flexible biconcave disks. Sickle cell anaemia however, contains an abnormal type of haemoglobin called ‘haemoglobin S’.
This protein changes the shape of the red blood cells into a sticky, rigid, sickle shape, especially at low oxygen levels. These sickle shaped cells are more fragile and carry less oxygen. They can also die prematurely which results in a shortage of red blood cells. Due to the fragile nature of the sickle red blood cells, they can break up and clog up blood vessels, causing nearby tissue to become starved of oxygen in episodes known as a ‘sickle cell crises. These crises’ can cause moderate pain and in severe cases, caused by lack of a regular oxygen supply, can lead to strokes and heart attacks.
The frequency of these crises differs from person to person so the exact frequency cannot be stated. They can occur several times in one year or not at all for several years, however it is known that they last between 5-7 days. Sickle cell anaemia is the most common genetic condition in England affecting, around 12,500 people and every one in 2,000 babies. The disease is much more common in people of African and Mediterranean descent and is also seen in people from South and Central America, the Caribbean, and the Middle East.