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What is Deep vein thrombosis and Causes
The formation of BLOOD clots in the veins, usually the deep or interior veins in the legs and lower pelvis. Physical inactivity is the primary cause of Deep vein thrombosis (DVT). The veins, which are not as muscular as the arteries, rely on the skeletal muscles to support them. The contraction and relaxation of skeletal muscles, such as occurs during walking and other physical activities, helps move blood through the veins. This support and massaging action is particularly important for function of the large veins in the legs, which transport significant volumes of blood toward the heart against pressure that can reach three times the force of gravity.
During periods of extended inactivity the skeletal muscles relax the tension they otherwise would exert against the veins, allowing the flow of blood to become sluggish. When other problems with the veins exist, such as VENOUS INSUFFICIENCY (inadequate function of the valves in the veins) and VARICOSE VEINS, blood may pool. The pooling provides opportunity for the blood to begin clotting, which can cause the localized occlusion and PAIN that characterizes DVT as well as HEART ATTACK, STROKE or PULMONARY EMBOLISM (blood clot in the LUNG) if a particle of the clot breaks away and travels through the bloodstream.
Birth control pills, even low-DOSE formulations, increase the risk for deep vein thrombosis, most significantly in women who also smoke.
The most effective approach for DVT is prevention, which for many people can be as simple as walking for a few minutes every couple hours during the day, even if only around a desk or lifting the legs as if marching in place. Additional risk factors include OBESITY, DIABETES, VARICOSE VEINS, PERIPHERAL VASCULAR DISEASE (PVD), and cigarette smoking. Doctors may recommend ANTICOAGULATION THERAPY as a further preventive measure to reduce the blood’s clotting ability for people who are at risk for developing Deep vein thrombosis (DVT). Though extended airline flights present a well-popularized risk for DVT, less than one tenth of 1 percent of the 2 million Americans who develop DVT do so as a result of flying.
Symptoms of Deep vein thrombosis (DVT)
Once the thrombosis, or clot, develops it blocks the flow of blood, which results in a backup of fluid that seeps into the surrounding tissues (edema). The clot also irritates the walls of the VEIN, causing INFLAMMATION. Symptoms of Deep vein thrombosis (DVT) include
- redness and swelling (edema) at the site of the clot
- tenderness or PAIN at the site of the clot
- FEVER and generalized discomfort
Deep vein thrombosis Diagnosis and treatment
The diagnostic path may include ULTRASOUND or VENOGRAM of the suspected occlusion, which typically provides the visualization necessary to confirm the diagnosis. Treatment typically consists of
- anticoagulation therapy to prevent the clot from enlarging or other clots from forming
- bed rest, with heat to the area to improve circulation, until the clot dissolves
- support stockings
People who have one experience with Deep vein thrombosis (DVT) face increased risk for subsequent DVTs and usually take prophylactic anticoagulation therapy to lower the risk. Lifestyle measures such as daily walking and other physical activity, SMOKING CESSATION, and weight loss if necessary are also key to preventing subsequent DVTs.