Deep vein thrombosis (DVT).

Occurs when a blood clot forms in a vein, usually in the legs or pelvis. DVT is also known as venous embolism, thrombophlebitis or phlebothrombosis. DVT is more likely in patients who have had orthopedic surgery, pelvic surgery, or abdominal and thoracic surgery. Patients with cancer and other chronic illnesses such as heart disease, including those who have suffered a recent heart attack, are also at high risk for developing DVT.

DVT can be chronic, with recurrent episodes. The three factors that contribute to DVT are:
1) changes in the content of the blood that clots more quickly,
2) radical changes in blood flow, and
3) irritation or damage to the lining the blood vessels (which may be caused by high blood pressure).

DVT is caused by blood clots forming in blood vessels, which form where the blood flow in the veins is restricted. This most often occurs in pockets in the deep veins of the legs or pelvic veins that are weakened or damaged. In some cases the development of deep vein thrombosis is in the arm near the shoulder, a condition known as Paget-Schrötter disease.

The most noticeable symptoms of DVT include swelling, pain and redness of the affected limb. In some cases, the visible veins near the surface of the skin may be swollen. These external symptoms, however, usually occur in less than half of patients. Part of the danger of the disease is that it is often silent. It makes sense for those with a family history of DVT to monitor their situation and have regular tests.