Deep Vein Thrombosis (DVT)
What is it?
A clot that forms in a blood vessel is called a thrombus. Deep vein thrombosis (DVT) is a blood clot in a deep-lying vein, usually in the legs. You may also see deep vein thrombosis referred to as venous thromboembolism, thrombophlebitis, or phlebothrombosis. Only clots that form in the deep veins have the potential to be dangerous.
Who gets it?
Statistics from the American Heart Association show that more than two million Americans develop deep vein thrombosis every year. It can occur as a major complication of orthopedic, pelvic, abdominal, or thoracic surgery. If you have cancer, severe varicose veins, are confined to bed, have suffered a recent heart attack or stroke, or have a chronic illness, such as congestive heart failure, you have a higher risk of developing deep vein thrombosis. Some individuals are prone to blood clots or the tendency may run in the family.
What causes it?
Deep vein thrombosis occurs when a person has an increased tendency for blood to clot, usually because of some type of cancer or medication; when there is an injury to the lining of a vein; or because blood flow is slow. Blood flow usually becomes sluggish in people who are bedridden for a long period of time because of illness, injury, or surgery. However, even otherwise healthy people can develop thrombosis from sitting for a long period time, such as on a long car trip or plane flight.
What are the symptoms?
Deep vein thrombosis has no symptoms at all in approximately half of the people who develop it. When symptoms do occur because the clot has blocked a major vein, they include swelling and tenderness in the calf, ankle, foot, or thigh area. The swollen area may also feel warm to the touch. Swelling may go down at night when the legs are supported or elevated. As deep vein thrombosis becomes more severe, the skin above the ankle may appear brown. This discoloration is caused by red blood cells that have seeped out of the swollen veins into the skin. If a blood clot is not too tightly attached to the wall of the vein, it can break off and travel with the blood to other organs in the body. This is called an embolism. A pulmonary embolism is a blood clot that lodges in the lungs and blocks the lung arteries. It is one of the most serious complications of deep vein thrombosis. About 60,000 people die of pulmonary embolism each year.
How is it diagnosed?
Deep vein thrombosis can be difficult to diagnose, either because the patient has no symptoms or because its symptoms can be caused by other conditions. If your doctor suspects deep vein thrombosis, he or she will order an ultrasound of your leg veins, a painless procedure in which high frequency sound waves produce an image of the veins and show any blockages. Other diagnostic tests that are sometimes used include impedance plethysmography (IPG), a test that checks blood pressures at different locations in the leg; contrast venography, in which a special dye that shows up on x-ray is injected into the veins; or computed tomography (CT) scans of the pelvis area. If pulmonary embolism is suspected, your doctor will also order chest x-rays.
What is the treatment?
Deep vein thrombosis is treated with a combination of drug therapy, bed rest, compression bandages, and elastic stockings. Medications include drugs that help to dissolve blood clots and anticoagulants that “thin” blood so blood clots are less likely to develop. Commonly used anticoagulants include heparin, which is injected into the blood stream, and
warfarin, which is taken orally. Patients with deep vein thrombosis can reduce swelling and pain by keeping the legs elevated as much as possible. Patients who are at risk for deep vein thrombosis and are having any type of surgery are frequently kept in pressure stockings before, during, and after surgery. These stockings are hooked to an electric pump, which automatically pumps them up, then releases the pressure. The pressure squeezes the calves and empties the veins, so it is more difficult for blood clots to form. Elastic support stockings are also recommended to squeeze the veins and keep blood flowing.
Self-care tips
If you are at risk for deep vein thrombosis, you can prevent it by taking an anticoagulant, under the supervision of your doctor. If you must take a trip where you will be sitting for long periods of time, be sure to get up and move around at regular intervals. Flexing and extending your legs, feet, and ankles about 10 times every 30 minutes will help to keep the blood flowing in the leg veins. If you wear elastic stockings, be sure to take them off each day to wash and dry them, and to clean and check your skin and give it some air. Make sure the stockings fit so there is no bunching. Elastic stockings that fit poorly will actually make your condition worse by blocking blood flow in the area where they have bunched up. Elevate your legs when sitting or lying down to keep blood flowing. If you have had surgery, get up and walk as soon as possible to lower your risk of deep vein thrombosis.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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