Minor injuries linked to dangerous blood clots
Publication Date:14/01/2008
Introduction
Minor injuries, such as those you might get playing tennis, could increase the risk of getting a blood clot in your leg, researchers have found. They say many people with these blood clots might have got them because of a torn muscle in the weeks beforehand.
What do we know already?
A blood clot in the deep veins of your legs can cause serious problems. It can be painful, and also some blood clots here can travel to the lungs, which can be life-threatening. Usually, these blood clots (called deep vein thrombosis, or DVT) can be treated with medicines.
Doctors don't know the causes of all DVTs. There are some clear risks – for example, staying still for a long time, such as on a long plane journey, having a big operation like a hip replacement, or having a major injury that means you can't move around afterwards, such as a broken leg.
Also, pregnant women are more likely to get DVTs, and certain medicines like HRT and the contraceptive pill can slightly increase the risk. But there are plenty of cases where doctors don't know what caused a person to get a DVT. So researchers set up a study to try to find out what else could cause them.
What does the new study say?
People who had minor injuries to the legs, such as a ruptured (torn) muscle or ligament, had more chance of having a DVT in the weeks following the injury. Knee and ankle sprains also increased the likelihood of DVT, although not as much as ruptured muscles or ligaments.
Injuries elsewhere on the body (not the legs) did not increase the likelihood of getting a DVT. The risk seemed to be temporary. The risk of getting a DVT after injury was highest 2 to 3 weeks after the injury, and the increased risk had disappeared 10 weeks after the injury.
Tell me more about the study's findings
The study looked at nearly 2,500 people who'd been treated for a DVT. It asked them about any injuries in the 3 months prior to getting the blood clot. The researchers took out all the people who'd had major injuries needing plaster casts, treatment in hospital or more than 4 days resting in bed. That's because we already know these major injuries increase your risk.
When they looked at minor injuries, they found that recent leg injuries, especially a rupture of the sural muscle (in the back of the calves), were about five times more common in people who'd had a DVT, compared to people of the same age and sex who hadn't had a DVT. Tennis players are prone to this particular injury.
Where does the study come from?
The study was carried out by researchers at the Leiden University in Leiden, The Netherlands. It was published in the Archives of Internal Medicine, a medical journal owned by the American Medical Association.
How reliable are the findings?
This type of study is good for finding links between things, for example the link between minor injuries and DVTs. But they can't prove for sure that the injury caused the blood clot. That's because other factors that the researchers don't know about might have been important.
However, the study was well carried out and the researchers tried to take account of things like people's ages and sexes, and whether they had a genetically increased risk of getting a DVT. So the results are likely to be quite reliable.
What does this mean for me?
If you play a lot of sports, you may worry that you're more likely to be injured and so more likely to get a blood clot in your leg. However, the risks from sport are likely to be outweighed by the benefits you get from taking healthy exercise. DVT is quite rare. Every year, about 1 in 5,000 people are diagnosed with a DVT.
The people most likely to get a DVT are:
- Older people (over 70)
- Pregnant women
- People having major operations, especially hip and knee replacements. But these people usually have drug treatment to prevent clots.
What should I do now?
If you've had a leg injury, especially a ruptured muscle or ligament, it's worth being aware of the symptoms of DVT. If you think you may have them, see your doctor at once. Symptoms of a DVT include:
- Swelling or pain in the thigh or calf of your leg
- Your leg feeling hot
- Your leg going red or purple in colour.
If you are worried about getting a blood clot on a long journey, especially a flight, doctors recommend that you try to exercise your legs while seated, for example by circling your feet and bending and stretching your legs, and get up to take short walks. Keeping your blood flowing helps prevent DVTs. You might want to consider wearing compression stockings, which seem to protect some people.
From:
van Stralen KJ, Rosendaal FR, Doggen CJM. Minor injuries as a risk factor for venous thrombosis. Archives of Internal Medicine. 2008; 168 : 21-26.
To find out more, see our information on deep vein thrombosis.
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This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
