What is Sickle Cell Disorder?
Sickle cell disorder is a serious inherited blood
disorder where the red blood
cells, which carry oxygen around the body, develop
Normal red blood cells
Sickled red blood cells
The disorder mainly affects people of African,
Caribbean, Middle Eastern, Eastern Mediterranean and Asian
origin. In the UK, sickle cell disorders are most
commonly seen in African and Caribbean people.
Normal red blood cells are flexible and disc-shaped, but in
sickle cell anaemia they can become rigid and shaped like a
crescent (or sickle).
The sickle-shaped cells contain defective haemoglobin, the
iron-rich protein that enables red blood cells to carry oxygen from
your lungs to the rest of the body.
The abnormal cells are also unable to move around as easily as
normal shaped cells and can block blood vessels, resulting in
tissue and organ damage and episodes of severe pain.
Such episodes are known as a sickle cell crisis or a
vaso-occlusive crisis. They can last from a few minutes to several
months, although on average most last five to seven days. The
abnormal blood cells also have a shorter lifespan and
aren't replaced as quickly as normal blood cells. This leads
to a shortage of red blood cells, known as anaemia.
Symptoms of anaemia include lethargy (a lack of energy),
tiredness and breathlessness, particularly after exercise.
What causes sickle cell disorder?
Sickle cell disorder is caused by a mutation (an abnormal
change) in the gene that instructs the body to produce
haemoglobin. The sickle cell gene is inherited (passed on between
family members). To get sickle cell disorder you have to inherit
the defective gene from both parents. If you only inherit the gene
from one parent, you have what's known as the sickle cell trait.
It's likely that your blood will contain some sickle cells,
but you'll be able to produce normal haemoglobin and won't usually
experience symptoms. However, you'll be a carrier of sickle cell
disorder and may pass the abnormal gene on to your
In England, about 250,000 people are thought to have the
sickle cell trait, with those of African-Caribbean origin
primarily affected. If two people with the sickle cell trait have a
child, there's a one in four chance that the child will be born
with sickle cell disorder.
Diagnosing and screening for sickle cell disorder
Sickle cell disorder can be diagnosed using a
simple blood test, which can be done at the centre, your GP, a
routine hospital admission or during pregnancy. All pregnant women
are offered screening for sickle cell as
part of their antenatal care. The blood is checked for
defective haemoglobin. A small level of defective haemoglobin would
indicate that a person has the sickle cell trait but not sickle
cell disorder. A high level would indicate sickle cell
People in high risk groups should be tested for the sickle cell
before having a general anaesthetic. This is because this type
of anaesthesia temporarily lowers the amount of oxygen in
the blood, which could be dangerous for someone with these blood
Treating sickle cell disorder
If you are diagnosed with sickle cell disorder, you should be
referred to a specialist sickle cell centre. Sickle cell centres
are specialist units usually based in large hospitals. The staff at
these units have a high level of expertise in treating people with
sickle cell disorder. A detailed plan outlining future medical care
will be drawn up and you'll be given information and support to
help manage your condition. Following simple lifestyle advice, such
as drinking plenty of fluids, can help reduce the risk of
experiencing a sickle cell crisis.
Sometimes, a person with sickle cell disorder will continue
to experience pain despite taking preventative measures. In such
cases, a medication may be called recommended.
Complications of sickle cell disorder
The symptoms of sickle cell disorder can have a significant
impact on a person's quality of life. If complications develop,
these can be very serious. Possible complications include:
- stroke - where the blood supply to part of the brain
is cut off
- increased vulnerability to infection
- acute chest syndrome - where the lungs suddenly lose their
ability to breathe in oxygen (often the result of an
- pulmonary hypertension - where the blood pressure inside
the blood vessels that connect the heart to the lungs becomes
However, following improvements in preventative treatment, many
complications associated with sickle cell disorder can be
The life expectancy of a person with sickle cell disorder has
increased significantly over recent decades. A person with the
condition can expect to live into their 50s and beyond.
When to seek urgent medical advice
Because of the risk of potentially life-threatening
complications, it's important to look out for any signs or symptoms
that the health of a person with sickle cell disorder has suddenly
deteriorated. These include:
- a high temperature (fever) of 38C (100.4F) or above
- breathing difficulties
- severe pain that develops during a sickle cell crisis that
can't be controlled using over-the-counter painkillers, such
as paracetamol or ibuprofen.