Deep vein thrombosis, abbreviated DVT, is a serious medical condition caused by a blood clot. It occurs when a clot, called a thrombosis, forms in a vessel that carries blood toward the heart. Such clots usually occur in the deep veins of the legs, but they can also occur in other parts of the body, such as the veins of an arm or abdominal organ. Once formed, the clot can enlarge over time. Without treatment, DVT can cause serious medical complications and even death.
In many cases, DVT causes no symptoms. But it can create pain and swelling in the affected area, caused by the blocked flow of blood. Sometimes, a scar forms in the blood vessel around the clot. The scarring may damage valves that help control the flow of blood through the vein. This damage can cause blood to build up in the surrounding tissues, leading to permanent swelling in the affected area. Occasionally, a clot can break off and travel through the veins, to the heart, and into the lungs. This results in a serious condition called a pulmonary embolism. It may cause no symptoms at all, or it may cause shortness of breath, chest pain, coughing up of blood, and even sudden death.
Causes.
Many conditions can cause blood clots to form in the deep veins. Such conditions include sitting or lying for prolonged periods in which the limbs, especially the legs, are immobile. DVT can occur on long airplane flights, during which people often sit for hours with little movement in cramped conditions. People who are immobile following surgery or recovering from fractures also have an increased risk of developing DVT. Other risk factors associated with DVT include pregnancy, smoking, certain medications, and medical conditions, such as cancer or obesity.
Most people who develop DVT have a combination of several risk factors. People who have experienced DVT in the past have an increased risk of developing the condition again. In addition, physicians believe that some people have a genetic (inborn) tendency to develop DVT.
Diagnosis and treatment.
Physicians may look for DVT or pulmonary embolism in patients with pain or swelling in a limb, shortness of breath, or chest pain. The diagnosis is usually made through medical imaging tests, such as an ultrasound for DVT or complex lung scans to look for a pulmonary embolism. Physicians may administer drugs called anticoagulants if they know or even suspect a patient has DVT. Anticoagulants work to prevent blood clotting, also called coagulation. Such treatment gives the body time to dissolve and absorb the blood clot naturally. Patients may need to continue taking anticoagulants for months. People who have a high chance of developing DVT, such as those who are found to have a genetic tendency for DVT, may need to take anticoagulants for the rest of their lives.
People can take preventive measures to lessen the chances of developing DVT. On long airplane flights, for example, a person can do leg exercises in the seat or take brief walks down the aisle. Wearing special elastic stockings can help prevent blood clots from forming in the legs. Drinking sufficient water may also help. For patients confined to a hospital bed, physicians may use anticoagulant medications or special machines that keep blood flowing in the legs.
See also Anticoagulant ; Embolism .
