Deep vein thrombosis (DVT) is a condition that occurs when a blood clot forms in a vein deep inside a part of the body. It mainly affects the large veins in the lower leg and thigh, but can occur in other deep veins such as in the arms and pelvis.
DVT is most common in adults over age 60. But it can occur at any age. When a clot breaks off and moves through the bloodstream, it is called an embolism. An embolism can get stuck in the blood vessels in the brain, lungs, heart, or another area, leading to severe damage.
Blood clots may form when something slows or changes the flow of blood in the veins. Risk factors include:
Blood is more likely to clot in someone who has certain problems or disorders, such as:
Sitting for long periods when traveling can increase the risk for DVT. This is most likely when you also have 1 or more of the risk factors listed above.
DVT mainly affects the large veins in the lower leg and thigh, most often on 1 side of the body. The clot can block blood flow and cause:
Your health care provider will perform a physical exam. The exam may show a red, swollen, or tender leg.
The 2 tests that are often done first to diagnose a DVT are:
Blood tests may be done to check if you have an increased chance of blood clotting, including:
Your provider will give you medicine to thin your blood (called an anticoagulant). This will keep more clots from forming or old ones from getting bigger.
Heparin is often the first drug you will receive.
Depending on your medical history, a drug called fondaparinux may be recommended by your doctor as an alternative to heparin.
A blood thinning drug, for example warfarin (Coumadin), is often started along with heparin. Examples of other drugs that may be prescribed include rivaroxaban, apixaban, dabigatran, and edoxaban. Your doctor will decide which medicine is right for you.
When you are taking a blood thinning drug, you are more likely to bleed, even from activities you have always done. If you are taking a blood thinner at home:
You will be told to wear a pressure (compression) stocking on your leg or legs. A pressure stocking improves blood flow in your legs and reduces your risk for complications from blood clots. It is important to wear it every day.
In rare cases, you may need surgery if medicines do not work. Surgery may involve:
Follow any other instructions you are given to treat your DVT.
DVT often goes away without a problem, but the condition can return. Some people may have long-term pain and swelling in the leg called post-phlebitic syndrome.
You may also have pain and changes in skin color. These symptoms can appear right away or you may not develop them for 1 or more years afterward. Wearing compression stockings during and after the DVT may help prevent this problem.
Blood clots in the thigh are more likely to break off and travel to the lungs (pulmonary embolus) than blood clots in the lower leg or other parts of the body.
Call your provider if you have symptoms of DVT.
Go to the emergency room or call the local emergency number (such as 911) if you have DVT and you develop:
To prevent deep vein thrombosis:
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.