Deep vein thrombosis commonly affects the leg veins (such as the femoral vein or the popliteal vein) or the deep veins of the pelvis.. A DVT can occur without symptoms, but in many cases the affected extremity will be painful, swollen, red, warm and the superficial veins may be engorged. The most serious complication of a DVT is that the clot could dislodge and travel to the lungs, which is called a pulmonary embolism (PE). DVT is a medical emergency, present in the lower extremity there is a chance of a PE killing the patient. A late complication of DVT is the post-phlebitic syndrome, which can manifest itself as edema (an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body).

Venous thrombosis occurs via three mechanisms: decreased flow rate of the blood, damage to the blood vessel wall and an increased tendency of the blood to clot (hypercoagulability). Several medical conditions can lead to DVT, such as compression of the veins, physical trauma, cancer, infections, certain inflammatory diseases and specific conditions such as stroke, or heart failure. There are several factors which can increase a person's risk for DVT, including certain drugs (such as estrogen or erythropoietin), surgery, hospitalization, immobilization (such as when orthopedic casts are used, or during long-haul flights, leading to economy class syndrome), smoking, obesity, and age.

Signs and Symptoms