Sickle cell anaemia is a genetic (inherited) blood disorder in which red blood cells, which carry oxygen around the body, develop abnormally.
Rather than being round and flexible, the sickle red blood cells become shaped like a crescent (or sickle).
These abnormal red blood cells can then clog sections of blood vessels leading to episodes of pain which can be severe. These episodes are called a sickle cell crisis (also known as a vaso-occlusive crisis).
They can last from a few minutes to several months, though on average most last five to seven days.
The abnormal blood cells have a shorter life-span and are not replaced as quickly as normal; this leads to a shortage of red blood cells, called anaemia. Symptoms of anaemia include tiredness and breathlessness; especially after exercise.
Read more about the symptoms of sickle cell anaemia.
Complications
Symptoms of sickle cell anaemia can have a significant impact on quality of life. Potential complications can be life-threatening.
They include:
- stroke – where the supply of blood to the brain becomes blocked
- acute chest syndrome – where the lungs suddenly lose their ability to breathe in oxygen; often as a result of infection
- increased vulnerability to infection
- pulmonary hypertension – where the blood pressure inside the blood vessels that run from the heart to the lungs becomes dangerously high
However, following improvements in preventative treatment, many complications associated with sickle cell anaemia can be avoided and most people with the condition live much longer than previously.
Read more about the complications of sickle cell anaemia.
When to seek urgent medical advice
Due to the risk of life-threatening conditions, it is important to look out for any signs or symptoms that the patient's health has suddenly deteriorated.
These include:
- high temperature (fever) of 38C (100.4F) or above
- severe pain that develops during a sickle cell crisis that cannot be controlled using over-the-counter painkillers, such as paracetamol or ibuprofen
- breathing difficulties
Read more about when to seek urgent medical advice.
Treating sickle cell anaemia
Treatment helps reduce the severity and frequency of the symptoms of sickle cell anaemia and prevent complications.
In some cases a person with sickle cell anaemia may require regular blood transfusions to help reduce the risks of complications.
Read more about the treatment of sickle cell anaemia.
What causes sickle cell anaemia?
Sickle cell anaemia is caused by a genetic mutation that affects normal development of red blood cells.
A genetic mutation is when the instructions found inside all living cells become scrambled in some way meaning one or more of the processes of the body do not work in the way they should.
The mutation that causes sickle cell anaemia is often referred to as the sickle cell trait.
It is estimated that around a quarter of a million people in England have the sickle cell trait; most of whom have African-Caribbean ancestry.
Having the sickle cell trait itself will not cause a person to develop sickle cell anaemia. But if two people with the trait conceive a child then there is a one in four chance that child will be born with sickle cell anaemia.
Read more about the causes of sickle cell anaemia.
Screening
Sickle cell anaemia can be diagnosed with a blood test.
In England, all pregnant women are offered screening (either a blood test or questionnaire) to find out if they are a carrier. If they are a carrier, the baby's father should be offered a screening blood test.
However, all babies born in the UK are tested for sickle cell anaemia as part of the heel-prick newborn screening test performed by the midwife.
Anyone from at risk groups having a general anaesthetic should be tested for the sickle cell trait or thalassaemia because a general anaesthetic temporarily lowers the amount of oxygen in the blood, which could be dangerous for someone with the condition.
Read more about screening for sickle cell anaemia.
