Deep vein thrombosis, or DVT, describes a condition in which blood clots form in the deep blood vessels of the legs and groin. If a blood clot forms in one of the leg veins, it can inhibit blood flow back to the heart. If a piece of the clot breaks off, it can be carried to the lungs, where it becomes a pulmonary embolism (PE). The main risk of DVT is that a clot or a piece of a clot will break off and travel to the lungs, causing PE. If left untreated, PE can be fatal. Most fatal cases of PE are a result of recurrence, rather than the initial episode. Since most PEs come from DVT, your doctor’s primary focus is to treat DVT.
What causes DVT?
DVT is associated with the slowing of blood flow in the legs and groin, and with injury to veins. When blood flow slows, blood clots can form on irregular areas along the blood vessel walls.
Risks include prolonged sitting, bed rest, or immobilization; recent surgery or trauma, especially hip surgery, gynecological surgery, heart surgery, or fractures; childbirth within the last 6 months; obesity; and the use of medications such as estrogen and birth control pills. Risks also include a history of polycythemia vera, malignant tumor, hypercoagulability (changes in the levels of blood clotting factors making the blood more likely to clot), disseminated intravascular coagulation (DIC), and dysfibrinogenia. DVT may be associated with, or may cause, pulmonary embolus(PE).
Who gets DVT?
About two million people experience DVT each year (approximately 2 out of 1,000 people). The condition is most commonly seen in adults over age 60. People at risk of developing DVT are those having surgery on their legs, hips, or knees; people who have cancer; and people who have been previously diagnosed with DVT. Also at risk of developing DVT are pregnant women, young people with badly broken bones in their legs, and people who are immobile.
Most people who have DVT do not know it. Only about 4 out of 100 people will have symptoms. Symptoms can include pain and swelling in the leg.
What are the symptoms of DVT?
Symptoms of DVT can include:
leg pain, tenderness or swelling in one leg only
increased warmth of one leg
changes in skin color of one leg, redness
skin discoloration, bluish
joint pain
How is DVT diagnosed?
Your doctor will take your history and perform a physical exam. He/she will look for a red, swollen, tender area of the leg, and a sharp pain when the foot is flexed upward.
Certain diagnostic tests and/or imaging procedures can help to diagnose DVT. They include:
venography
arteriography
blood flow studies
Doppler ultrasound exam of an extremity
plethysmography
How is DVT treated?
People with DVT and PE usually are treated with medications that prevent more clots from forming (oral anticoagulants or antiplatelet medications). Occasionally, medication is used to dissolve the clot. In rare circumstances, clots may be surgically removed. Sometimes physicians place filters in your blood vessels to keep the clots from reaching the lung. If you are being treated for DVT, such therapy can help reduce the risk of PE.
Bed rest may be recommended until the symptoms are relieved. The leg may be elevated to reduce swelling. Avoid prolonged sitting. Warm, moist heat to the area may help relieve pain.