Blood clotting generally is a good thing. Without it a person could bleed to death from a simple paper cut or by flossing their teeth. On the flip side, however, blood clots can also become a life threatening occurrence.
Our bodies use a complex orchestration of various chemical factors and blood cells within the vascular system to stop bleeding. We call it the clotting cascade. When an injury occurs to a blood vessel wall, these cells and clotting factors immediately spring into action to form a clot, or thrombus, and prevent blood loss.
When an unwanted clot forms in one of the major veins of the body, such as in the leg, the condition is called a deep vein thrombosis or DVT. This can occur due to sluggish or blocked blood flow in the vein, damage to the inside wall of the blood vessel, or an abnormal tendency of the blood to clot.
DVTs occur at a rate of about 1 in 1,000 persons in the U.S. One-half of these cases arise in those who are hospitalized or in a nursing home. Prolonged immobility is a major risk factor for developing a DVT. This includes recent extended travel sitting in a car or on a plane.
Other risk factors for getting a blood clot, include: advancing age, recent surgery, trauma/fracture of an extremity, cancer, congestive heart failure, inherited blood clotting disorders, and certain drugs, particularly estrogen and birth control pills. Smoking and obesity also put people at increased risk.
In and of itself, a clot in a vein does not pose much of a threat to the affected individual. After all, the body is designed to reroute the blood through other veins to return it back to the heart. However, a clot can detach from the vessel wall and travel to the heart and lungs. A traveling blood clot is called an embolus and one that ends up in the lungs is called a pulmonary embolus, or PE. Clots in the lungs can cause lung cell damage, impaired oxygen exchange, and can even lead to death.
DVTs develop most commonly in the large, deep veins of the legs and pelvis. It is much less common to see a superficial vein, such as a varicose vein, leading to a serious clot. Generally, a DVT affects only one leg.
Symptoms of a DVT, include: swelling in the extremity, pain, discoloration or redness, warmth, and tenderness. When someone presents to the clinic a swollen leg, the doctor must look at their risk factors, symptoms and signs to determine if a blood clot is a possibility. Blood tests can sometimes aid in the diagnosis. An ultrasound or Venous Doppler of the affected extremity is generally done to look for a clot and assess the blood flow in the extremity.
If a DVT is found, the patient is put on an anticoagulant medication. These medications interrupt the clotting cascade and are used to prevent further extension and complications from the clot. Frequent blood testing is necessary to keep the blood levels of these medications within a therapeutic range.
In many cases, preventing a DVT is outside of our control. But, there are ways to reduce some of your risks; quitting smoking, losing weight, and exercising are the most important.
During prolonged travel, take time to get up, move around, and stretch/exercise your legs.
The content in this column is for informational purposes only. Consult your physician for appropriate individual treatment. Dr. Reynolds practices Family Medicine in Chesterfield.