What causes blood clots?
Sarita Sharma,MD, is an internist on staff at Banner Estrella Medical Center in Phoenix.
Question: Several of my family members have developed blood clots in their legs at different points in time. What causes these blood clots and what can I do to recognize and prevent them?
Answer: A blood clot that forms in the leg is called a deep vein thrombosis (DVT). Every year more than 300,000 Americans are diagnosed with a DVT, with far more instances going unrecognized.
DVTs can develop for a variety of reasons. Family history, prolonged periods of sitting or lying down, recent injury or surgery, heart disease, a blood-clotting disorder, obesity, pregnancy, birth control pills, and smoking are just a few of the known risk factors.
Symptoms aren’t always noticeable, but when they are, they can include pain, swelling, discoloration, and warmth in the affected leg. The most common treatment for a DVT is anticoagulant medications that help reduce the risk of clotting.
Of great concern are blood clots that break free and travel to other parts of the body, such as the brain, heart or lungs. A clot that travels to the lungs can block an artery and cause a pulmonary embolism, which is potentially fatal. Pulmonary embolisms, which require immediate medical attention, can often seem like a heart attack or pneumonia, based on symptoms such as shortness of breath, chest discomfort or pain, coughing up blood, or dizziness and fainting.
There are a number of strategies for reducing the risk of DVTs, and more importantly, pulmonary embolisms. The first is being able to recognize the signs and symptoms. It is also important to take all medications as prescribed after an injury or surgery, try to move around or at least exercise your leg muscles if you have to sit or lay down for prolonged periods of time, stop smoking, control your weight and blood pressure, wear compression stockings, and make regularly scheduled appointments with your physician, especially if you have a history of blood clots.
Reviewed June 2010