Deep venous thrombosis is a condition in which a blood clot forms in a vein that is deep inside the body.
DVT; Blood clot in the legs; Thromboembolism; Post-phlebitic syndrome; Post-thrombotic syndrome
Deep venous thrombosis (DVT) mainly affects the large veins in the lower leg and thigh. The clot can block blood flow and cause swelling and pain. When a clot breaks off and moves through the bloodstream, this is called an embolism. An embolism can get stuck in the brain, lungs, heart, or other area, leading to severe damage.
Blood clots may form when something slows or changes the flow of blood in the veins. Risk factors include:
You're also more likely to develop DVT if you have any of the following conditions:
DVTs are most common in adults over age 60, but can occur at any age.
Sitting for long periods when traveling can increase the risk of DVTs. This is most likely when one or more of the risk factors listed above are also present.
Your health care provider will perform a physical exam. The exam may show a red, swollen, or tender leg.
The following tests may be done:
Blood tests may be done to check if there is increased chance of blood clotting (hypercoagulability). Such tests include:
This list is not all-inclusive.
Your doctor will give you medicine to thin your blood (called an anticoagulant). This will keep more clots from forming or old ones from getting bigger. These drugs cannot dissolve existing clots.
Heparin is usually the first drug given.
A drug called warfarin (Coumadin) will be started along with heparin. Warfarin is taken by mouth. It takes several days to fully work. Heparin is not stopped until the warfarin has been at the right dose for at least 24 hours. You will most likely take warfarin at least 3 months. Some people must take it for the rest of their lives, depending on their risk for another clot.
When you are taking warfarin, you may be more likely to bleed, even from activities you have always done.
Changing how you take your warfarin, taking other medicines, and eating certain foods all can change the way the warfarin works in your body. If this happens, you may be more likely to form a clot or have bleeding problems.
You will be given pressure stocking prescribed by your doctor. They will improve blood flow in your legs, and reduce your risk for blood clots. It is important to wear these every day.
In rare cases, surgery may be needed if medicines do not work. Surgery may involve:
Many DVTs disappear without a problem, but they can return. Some people may have long-term pain and swelling in the leg known as post-phlebitic syndrome. Wearing tight (compression) stockings during and after the DVT may help prevent this problem.
Blood clots in the thigh are more likely to break off and cause pulmonary embolism (PE) than blood clots in the lower leg or other parts of the body.
A blood clot can break free in the leg and travel to the lungs (pulmonary embolus) or anywhere else in the body, and can be life threatening. Rapid treatment of DVT helps prevent this problem.
Post-phlebitic syndrome refers to long-term swelling (edema) in the leg that had the deep vein thrombosis. Changes in skin color and pain can also be present. These symptoms may be noticed right away, or may not develop for one or more years afterward. This problem is called post-thrombotic syndrome.
Call your health care 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 chest pain, difficulty breathing, coughing blood, fainting, loss of consciousness, or other severe symptoms.
Wear the pressure stockings your doctor prescribed. They will improve blood flow in your legs and reduce your risk for blood clots.
Doctors may prescribe blood thinners to help prevent DVT in people at high risk, or those who are undergoing high-risk surgery.
Moving your legs often during long plane trips, car trips, and other situations in which you are sitting or lying down for long periods of time can also help prevent DVT. People at very high risk for blood clots may need heparin shots when they are on a flight that lasts longer than 4 hours.
Do not smoke. If you smoke, quit. Women who are taking estrogen must stop smoking. See: Smoking - tips on how to quit.
Geerts WH, Berggvist D, Pineo GF, et al. American College of Chest Physicians. Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6 Suppl):381S-453S.
Snow V, Qaseem A, Barry P, et al. Management of venous thromboembolism: a clinical practice guideline from the American College of Physicians and the American Academy of Family Physicians. Ann Intern Med. 2007;146(3):204-210.