I have been getting blood clots in my legs ever since I was 19 years old. I am female and am now 33. Most of the clots are superficial, but back in 1994, I did have a deep vein thrombosis that required a 14-day hospital stay on cumadin and heparin. I quit smoking (a pack a week) over two years ago. But I still get small clots here and there. The doctors keep asking if I hit my legs on anything but I don’t. I have asked why this could happen but get no explanations. Do you have any insight regarding this problem?
When our organ systems are functioning normally, we often don’t think about the complex biochemical interactions necessary to keep them that way. The clotting of blood is one such system that even doctors seldom think about unless they are specialized in the area. I think the doctors caring for you today should be giving a bit more thought to your history as you have recounted it.
We all know, of course, that blood is the fluid running around in our arteries, veins and capillaries, but we seldom think about it unless we cut ourselves and bleed. Living creatures have developed a system, called clotting, to prevent us from losing all our blood because of a minor cut. Disorders of clotting — for example, hemophilia — have been known for a long time, and their inheritance and the specific defects causing them have been pretty well worked out.
What has not been so well understood until recent years is what causes our blood to clot when we don’t want it to; for example, in a vein in the legs. Such abnormal clotting is termed a thrombosis, and can occur in both veins and arteries. The well-known coronary thrombosis is an abnormal clot in a coronary artery that causes a heart attack. Thrombosis in veins can also cause problems, the most serious occurring when the thrombosis breaks loose from the vein in which it formed and travels with the blood stream up to the lungs, where it causes a pulmonary embolism. (An embolism is caused by a clot or abnormal material in the blood stream getting stuck in the artery and blocking it.) Doctors often refer to the process as “thromboembolism.”
People with normal blood clotting can form thromboses under unusual circumstances, such as orthopedic surgery, trauma, prolonged immobilization, congestive heart failure, or during pregnancy. However, someone who develops a thrombosis at a young age with no obvious cause may have one of the inherited disorders that lead to increased clotting. You didn’t mention any instances of thromboembolism in your relatives, but if you do know of any, that would make the case for an inherited defect even stronger. Women who develop a thrombosis while pregnant or while taking birth control pills have a 30 percent chance of having the most common of these disorders, called a Factor V Leiden mutation.
Other factors that can lead to increased thromboembolism are antithrombin deficiency, found to a mild degree in one in 2,000 people, and the less common deficiencies of Protein S or Protein C. There are tests for all of these defects. People with antithrombin deficiency should be on lifetime anticoagulation (taking medication to prevent blood clotting). Anticoagulation for the other deficiencies depends on the number of documented thrombotic events. Since you have had at least one deep vein thrombosis, as well as several less dangerous superficial thromboses, you might be a candidate for anticoagulation. All women with these defects should avoid birth control pills, and if not on anticoagulation should take an aspirin tablet daily for its antithrombotic effects.
I think that with your history, you should insist on a referral to a hematologist interested in clotting for additional testing and consultation.