Deep vein thrombosis is a blood clot that develops within a deep vein in the body, usually in the leg. Blood clots that develop in a vein can also be known as venous thrombosis.
DVT usually occurs in a deep leg vein, a larger vein that runs through the muscles of the calf and thigh.
It can cause pain and swelling in the leg, this can lead to complications such as pulmonary embolism (this is a blocked blood vessel in your lungs, this can be life threatening if not treated quickly) It occurs when a piece of blood clot breaks off into the bloodstreams and blocks one of the blood vessels in the lungs.
DVT and pulmonary embolism together are known as venous thromboembolism (VTE).
The symptoms of DVT can include pain, swelling and tenderness in one of your legs (usually the calf area) a heavy ache in the affected area, warm skin in the area of the clot and red skin at the back of your leg. In some cases DVT will show no symptoms at all.
DVT will usually only affect one leg, although not always.
Each year DVT affects around 1 person in every 1000 in the UK.
Anyone can develop DVT but it becomes more common over the age of 40. As well as age there are also a number of other factors that can increase your risk of DVT:
- Having a history of DVT or pulmonary embolism.
- Having a family history of blood clots.
- Being inactive for long periods of time, such as after an operation or a long haul journey.
- Blood vessel damage.
- Having certain conditions or treatments that cause your blood to clot more easily than normal.
- Being pregnant.
- Being overweight or obese.
The combined contraceptive pill and hormone replacement therapy (HRT) both contain the female hormone Oestrogen, which causes the blood to clot more easily. Your risk of developing DVT is slightly increased if you are taking either of these.
It can be difficult to diagnose DVT from symptoms alone; your GP will most probably advise a blood test or ultrasound scan. The blood test to look for DVT is a specialised one called a D-Dimer test.
This test detects pieces of blood clot that may have been broken down and are loose in your bloodstream. If there are large numbers of fragments found, the more likely is that you could have a clot in your vein.
However the D dimer test isn’t always reliable because blood clot fragments can increase after an operation, injury or even during pregnancy. Additional tests to confirm if you have DVT or not will usually need to be carried out.
An ultrasound scan can be used to detect clots in your veins, this will usually take between 20-40 minutes and will not be painful, you will be asked to wear loose fitting clothing and the ultrasound will be applied from the top of the groin down the leg.
If you get diagnosed with DVT, you will most probably be given a medicine called Anticoagulant. These anticoagulant medicines work by interrupting the process involved in the formation of blood clots. They are also known as blood thinning medicines, although they do not actually do this.
The length of time you need to take these medicines will depend on each case and why it has been prescribed. In many cases treatment will be a lifelong thing.