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Deep Vein Thrombosis (DVT)

Deep vein thrombosis, commonly referred to as "DVT," occurs when a blood clot, or thrombus, develops in the large veins of the legs or pelvic area. Some DVTs may cause no pain, whereas others can be quite painful. With prompt diagnosis and treatment, the majority of DVTs are not life threatening.

However, a blood clot, or embolus, that forms in the invisible "deep veins" can be an immediate threat to your life rather than a clot that forms in the visible "superficial" veins, the ones beneath your skin. A clot that forms in the large, deep veins is more likely to break free and travel through the vein. When an embolus travels from the legs or pelvic areas and lodges in a lung artery, the condition is known as a pulmonary embolism (PE), a potentially fatal condition if not immediately diagnosed and treated.

Causes of DVT

Generally, a DVT is caused by a combination of two or three underlying conditions: slow or sluggish blood flow through a deep vein, a tendency for a person's blood to clot quickly, or irritation or inflammation of the inner lining of the vein. Irritation or inflammation of veins occurs when a leg vein is injured by a major accident or medical procedure.

Risk Factors for DVT

DVT occurs in about two million Americans each year and affects men and women, all ethnic groups and social levels. While it is most common in adults over the age of 40 and found more frequently in elderly patients, DVT can occur at any age. As noted previously, other conditions may increase one's risk, and individuals who smoke and who do not exercise are at increased risk.

Specific risk factors for DVT are:

  • Recent major surgery especially hip and knee orthopedic surgeries or those requiring prolonged bed rest
  • Cancer and its treatment
  • Activity that restricts walking and movement such as prolonged air or car travel
  • Major trauma or injuries to the leg
  • Previous DVT or PE
  • Hospitalization with an acute medical illness such as heart attack or stroke
  • Pregnancy, especially during the late stages or around the time of delivery
  • Use of birth control pills, hormone replacement therapy or estrogen treatment
  • Family history of DVT or PE
  • Obesity and lack of exercise
  • Smoking
  • Varicose veins
  • Chronic respiratory failure
  • Congestive heart failure

Symptoms of DVT

Approximately half of those with DVT never have recognized symptoms. When symptoms are present, the most common is leg pain and tenderness in the calf muscles, or swelling or a change in color of one leg to purple or blue. These signs and symptoms may appear suddenly or may steadily develop over a short time. If you observe these signs or symptoms, contact your physician immediately. If you do not have a physician, Rex HealthNet can provide a referral.

Symptoms are quite different if the clot breaks loose and travels to the lungs, causing a pulmonary embolism (PE). The symptoms of PE include chest pain, shortness of breath, rapid pulse or a cough. There may also be a feeling of apprehension, sweating or fainting. Such symptoms are not specific to a PE and can occur with pneumonia, heart attack and other medical conditions. These critical symptoms demand immediate medical attention.

Diagnosis of DVT

DVT can be suspected after a clinical exam and by identifying associated risk factors, but an accurate diagnosis cannot be made without additional testing. An ultrasound scan of the legs is usually ordered, because it is highly accurate, non-invasive and relatively painless. During the ultrasound scan, any blood clots in the vein are displayed on a monitor. A specific blood test may be performed to measure "D-dimer" as a sign of recent clotting. When this test is negative, it is very unlikely that you may have suffered a DVT. However, even with these excellent tests, there are occasions requiring more accurate information for a diagnosis. A venogram or phlebogram, a test in which dye is injected into a vein in the foot and an x-ray is taken, might be performed to more clearly view the blood flow within the leg veins. Phlebograms are rarely ordered today but are helpful when DVT is severe and clot dissolving therapies or surgical therapies may need to be considered.