Reviewed by Brian R. Robinson, MDA deep vein thrombosis (DVT) is a blood clot found in a vein that accompanies an artery, known as a deep vein.
DVT usually affects veins in the lower leg and thigh, which comprise of the largest, most central veins in the body. When a large clot (or thrombus) forms, it may interfere with circulation or break off and embolize, or move though the blood stream where it can and can lodge in any area, causing severe damage to the part of the body where it settles (for example, in the lung as a pulmonary embolism, or PE). DVT occurs in approximately 2 out of 1,000 people, most of who are over age 60. DVT causes problems both in the deep veins where it originates and due to embolization in the lungs and other locations in the body.Risk factors for DVT include:
• Prolonged bed rest or immobilization
• Recent surgery, fracture, or trauma
• Recent childbirth
• Obesity
• Use of medications such as birth control pills or estrogen
The clinical diagnosis of DVT is difficult. The classic signs and symptoms of DVT include pain, tenderness, and swelling in the affected leg. Other associated nonspecific findings are warmth, redness, a palpable clot within the leg, and pain when flexing the foot towards the head. When a patient has these symptoms, the diagnosis of DVT may be likely. However, no patient should be treated based on clinical findings alone because even if a patient has a swollen, painful, congested leg that appears to strongly suggest DVT, the chance that DVT is the correct diagnosis is not absolute. Similarly, an absence of signs and symptoms does not rule out DVT because most cases do not display the classic symptoms. Diagnostic tests must be performed whenever a DVT is suspected. Anatomic imaging of the leg vein is accomplished via venography, ultrasound, and MRI, and this range of tests can usually provide a more conclusive diagnosis.
