sickle cell disorder – evolution gone wrong?
by Nick Chandler
We all have red blood cells. There are literally millions of them flowing through our bodies all the time. They are tiny; you would need thousands of them to make up the size of a pinhead. It is these minute doughnut shaped cells that transport oxygen from our lungs around our bodies to our muscles.
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'Sickle cells' are red blood cells with one important difference: when they release their oxygen they become hard, sticky and change their shape. They end up crescent shaped, hence the name 'sickle'. The trouble is that when these hard and pointy blood cells try to pass through narrow blood tubes, they get stuck, break apart and can clog the flow of the ordinary blood. In the carrier of the sickle cells, this results in pain, damage to anything the blood passes through, and a low red blood cell count (see symptoms, below).
origins
In a curious case of the human body evolving to improve its chances of survival, sickle cells are, in a way, good for you. In some cases, they actually reduce your chances of getting malaria. Initial hints came from a study that linked the geographical distribution of mosquitoes that carried the malaria parasite and the geographical distribution of people with Sickle Cell Disorder: the two regions virtually overlapped. Scientists put two and two together and discovered that children who had inherited sickle cells from their parents were more likely to survive malaria. This explains why today we see that people with Afro-Caribbean or Asian ancestry are the predominant groups who suffer from Sickle Cell Disorder.
how is it transmitted?
This is a little bit complicated… First of all, Sickle Cell Disorder can be divided in to two categories: Sickle Cell Disease and Sickle Cell Trait. The Disease is the one where some of the blood cells go 'sickle' shaped, as described above, and is the one that causes all the problems. If you have the Trait then all your blood cells will be the normal doughnut shape, and you are unlikely to suffer any side effects.
The only way that you can get the Disease is if both your natural parents have a Sickle Cell Disorder. That is, the Disease, the Trait, or a combination of the two. If only one of your natural parents has the Disease or the Trait then you are only likely to get the Sickle Cell Trait. In some ways, Sickle Cell Trait is no bad thing – it does not develop into Sickle Cell Disease and it partially protects you from malaria. But, it has obvious implications if you want to have a baby with someone else who also has Sickle Cell Disease or Sickle Cell Trait (see having children, below).
how could it affect you?
symptoms
The problem with the sickle cells is that they are easily damaged and do not last as long as ordinary red blood cells. This can result in tiredness as the body catches up and tries to make more blood cells. When cells turn sickle shaped, the blockages that they cause result in pain and swelling. These pain attacks can last from hours to months, and often result in the sufferer being admitted to hospital where they are dosed up with strong painkillers. Ninety per cent of hospital admissions that involve Sickle Cell Disorder are for these pain attacks. Some of the more serious problems that Sickle Cell Disease can cause include strokes, increased chance of infections, leg ulcers, yellow eyes, kidney damage, painful erections for men, a low red blood cell count (anaemia) and delayed growth.
easing the suffering at home
The damage caused by the sickle cells to the kidneys reduces the amount of water the kidneys can retain. Because of this, people with Sickle Cell Disease tend to have to urinate more often, and so dehydration is more likely to occur. To combat this, sufferers need to drink water, and lots of it. An adult sufferer of average weight is advised to drink up to about nine pints of the stuff a day!
Hot baths and keeping warm as well as a healthy diet, which includes plenty of fresh fruit and veg, will help to reduce the frequency, duration and severity of the symptoms of the disease.
As sickle cell sufferers are more prone to infections, they are advised to avoid contact with crowds, where the chance of catching infections is increased. Any conditions that increase oxygen needs – such as physical overexertion or stress – should also be avoided, as should smoking and exposure to second hand smoke, both of which may trigger acute chest syndrome.
having children
This is a decision that must be taken carefully so as to avoid passing on the disease to your offspring. Remember, it is possible for both you and your partner to have Sickle Cell Trait without knowing it, and, if you both did, any children you have would have a 25 per cent chance of inheriting Sickle Cell Disease.
sickle cell sufferers in the UK
Because of the link to areas where malaria is rife, Sickle Cell Disorder in the UK predominantly affects people of African, Caribbean or Asian descent. With a large proportion of the sufferers now approaching the age of parenthood, the number of people with Sickle Cell Disorder is predicted to rise. It is estimated that by 2008 there will be 18,000 sufferers in the UK.
how do I know if I have Sickle Cell Disorder?
People with Sickle Cell Disease are likely to be suffering from one of the symptoms mentioned above, the most common being acute pain attacks. The only sure way to find out if you have the disease or the trait is to have a simple blood test. Your GP can arrange for this. The medical name for this test is 'haemoglobin electrophoresis'.
living with sickle cells – a face to the disease
Fans of the R&B group, TLC, may think they know a lot about the three divas that make up the band. What they probably don't know is that the lead singer Tionne Watkins, better known as T-Boz, has Sickle Cell Disease and has to interrupt her performing and recording schedule to make frequent trips to hospital. Tionne talks about the times during her teens when she was unable to go swimming because the water was too cold and had to drink special baby milk for her bones. At times the disease has left her unable to walk or use her arms. "Yeah, I get sick," she admits, "but I don't let it take over me. I stay positive".
what is the cure?
Sickle cell disease is a life long condition, and there isn't a cure available yet. However, research is ongoing, both into ways to treat the condition, and in the meantime into making life as normal as possible for people with the condition by managing the disease and its associated pain. Hopes are currently resting on drug treatments, stem cell research, gene therapy and bone marrow transplants. Cognitive Behavioural Therapy (CBT) has been shown to be effective in controlling illness and pain, and dietary factors and supplements can alleviate some of the symptoms. Counselling is also available for people with sickle cell disorders and their families (see help and info, below).
help and info
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organisations
Sickle Cell Society
54 Station Road
London NW10 4UA
Tel: 020 8961 7795
E-mail: info@sicklecellsociety.org
Website: www.sicklecellsociety.org
UK based organisation committed to raising funds to promote education and providing information, counselling and caring for those with Sickle Cell Disorders and their families. The website includes research findings and pain management techniques, news, teaching resources, events, employment information, information for health professionals, and a publication listing.
The Haemoglobinopathy Association of Counsellors (STAC)
SW London Sickle Cell & Thalassaemia Centre
Balham Health Centre
120 Bedford Hill
London SW12 9HP
Tel: 020 8700 0615
E-mail: sicklethal.balham@swlondon.nhs.uk
Website: www.stacuk.org
A national organisation for counsellors and other professionals dedicated to providing a service and support for those "at risk" of sickle cell and related conditions. The website has a list of sickle cell centres, counsellors and specialist services throughout the UK.
websites
BBC Health – case study
www.bbc.co.uk/health/awareness/sickle_qa.shtml
Patrick Johnson, aged 33, talks about what is it like to live with sickle cell.
Managing Sickle Cell Disease
www.studentbmj.com/back_issues/
1203/education/450.html
Article from December 2003 discussing the progress being made in improving the symptoms of sickle cell disease.
NHS Sickle Cell & Thalassaemia Screening Programme
www.kcl-phs.org.uk/haemscreening
Aims to establish high quality newborn screening programmes for sickle cell disorders and antenatal screening programmes for sickle cell and thalassaemia. It is committed to ensuring that informed decision-making by women and their families is integral to the programme.
Sickle Central
www.sickle-thalassaemia.org/index.html
Website of the Brent Sickle Cell and Thalassaemia Centre, with information, useful links and details of their support group and other specialist centres in the UK.
UC Davis Health System – Sickle Cell Disease
www.ucdmc.ucdavis.edu/healthconsumers/health/000058.shtml
A thorough article covering all aspects of the Sickle Cell Disease, from symptoms to a comprehensive study of potential treatments.
reading
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Need to Know: Sickle Cell Disorder by Oliver Gillie (Heinemann Library, 2004) |
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Hope and Destiny: A Patient's and Parent's Guide to Sickle Cell Anemia by Alan Sacerdote and Allen Platt (Independent Publishers Group, 2001) |
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What Does It Mean to Have Sickle Cell Anaemia? by Louise Spilsbury (Heinemann Library, 2002) |
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(July 2004, resources updated January 2005)
