Deep venous thrombosis 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 the deep veins in the arms.
Deep vein thrombosis (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, 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:
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 of DVT. This is most likely when you also have one or more of the risk factors listed above.
DVT mainly affects the large veins in the lower leg and thigh, almost always on one 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 two 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 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.
Heparin is usually the first drug you will receive.
Depending on your medical history, fondaparinux may be recommended by your doctor as an alternative to heparin.
A blood-thinning drug, for example warfarin (Coumadin), is usually started along with heparin.
When you are taking warfarin, you are more likely to bleed, even from activities you have always done. If you are taking warfarin at home:
You will be given a pressure (compression) stocking to wear 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 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:
To prevent deep vein thrombosis:
Reviewed By: Rita Nanda, MD, Assistant Professor of Medicine, Section of Hematology/Oncology, University of Chicago Medicine, Chicago, IL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.