Deep Vein Thrombosis
Topic Overview
What is deep vein thrombosis?
Deep vein thrombosis (DVT) is a blood clot (thrombus) in a deep vein, usually in the legs.
Clots can form in superficial veins (called superficial thrombophlebitis or phlebitis) and in deep veins. While blood clots in superficial veins rarely cause serious problems, clots in deep veins (deep vein thrombosis) require immediate medical care. See pictures of a developing blood clot
and the leg veins
These clots are dangerous because they can break loose and then travel through the bloodstream to the lungs, causing a pulmonary embolism. A pulmonary embolism is often life-threatening. DVT can also cause long-lasting problems. DVT may damage the vein and cause the leg to ache, swell, and change colour. It can also cause leg sores.
Blood clots most often develop in the calf and thigh veins, and less often in the arm veins or pelvic veins. This topic focuses on blood clots in the deep veins of the legs, but diagnosis and treatment of DVT in other parts of the body are similar.
What causes deep vein clots to form?
Blood clots can form in veins when you are inactive. For example, clots can form if you are paralyzed or bedridden or must sit while on a long flight or car trip. Surgery or an injury can damage your blood vessels and cause a clot to form. Cancer can also cause deep vein thrombosis. Some people have blood that clots too easily, a problem that may run in families.
What are the symptoms?
Symptoms of DVT include swelling of the affected leg. Also, the leg may feel warm and look redder than the other leg. The calf or thigh may ache or feel tender when you touch or squeeze it or when you stand or move. Pain may get worse and last longer or become constant.
If a blood clot is small, it may not cause symptoms. In some cases, pulmonary embolism is the first sign that you have DVT.
How is deep vein thrombosis diagnosed?
If your doctor suspects that you have DVT, you probably will have an ultrasound test to measure the blood flow through your veins and help find any clots that might be blocking the flow. Other tests, such as a venogram, are sometimes used if ultrasound results are unclear. A venogram is an X-ray test that takes pictures of the blood flow through the veins.
How is it treated?
Treatment begins right away to reduce the chance that the blood clot will grow or that a piece of the clot might break loose and flow to your lungs.
Treatment for DVT usually involves taking blood thinners (anticoagulants) such as heparin and warfarin (Coumadin, for example). Heparin is given through a vein (intravenously, or IV) or as an injection. Warfarin is given as a pill. Treatment usually involves taking blood thinners for at least 3 months to prevent existing clots from growing.
After this first course of blood thinners, your doctor may want you to keep taking a lower dose of warfarin to prevent deep vein clots from happening again. He or she may need to adjust the dose of your medicine. You will have blood tests often so your doctor can see how well the blood thinners are working.
Your doctor also may recommend that you prop up or elevate your leg when possible, use a heating pad, take walks, and wear tight-fitting stockings. These measures may help reduce the pain and swelling that can happen with DVT.
In rare cases, a vena cava filter may be inserted into a vein to help prevent blood clots from travelling to the lungs. This device is usually only used if a person is at high risk for pulmonary embolism and is not able to take blood thinners. It may also be used if you have DVT that comes back again or you had a pulmonary embolism while taking blood thinners.
How can deep vein thrombosis be prevented?
There are things you can do to prevent deep vein thrombosis. Many doctors recommend that you wear compression stockings during a journey longer than 8 hours. On long flights, walk up and down the aisle hourly, flex and point your feet every 20 minutes while sitting, drink plenty of water, and avoid alcohol and beverages with caffeine.
Frequently Asked Questions
Learning about deep vein thrombosis:
Being diagnosed:
Getting treatment:
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| Author: | Merrill Hayden Nancy Reid | Last Updated: April 5, 2006 |
| Medical Review: | Adam Husney, MD - Family Medicine Jeffrey S. Ginsberg, MD - Hematology | |
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