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What causes deep vein thrombosis?

This question was asked in Aurora, Colorado and has 4 answer(s) as of 08/30/2013.
Do varicose and spider veins cause deep vein thrombosis? How is it that clots form in the blood and can it be due to having bulging varicose veins because it looks like there are clots in my big varicose veins.


Doctors Answers (4)

Deep Vein Thrombosis (DVT) is a clot in the deep vein system located far below the skin in a large vein traveling through muscle or over bone. These clots are potentially dangerous as the clot may break free from its attachment to the vein wall and travel through the body until it passes through the heart and enters the lungs. A small DVT clot that moves to the lungs can cause severe shortness of breath and a large clot can be immediately fatal. If the clot remains in the leg, the symptoms are often mild and easily missed with single leg swelling and possibly soreness but often not painful. The DVT can be diagnosed by an ultrasound exam and treated by limiting movement (bed rest) with anticoagulants to dissolve the clot. The causes of DVT's include larger traumas and surgeries, especially orthopedic surgeries including knee and hip replacements, immobility for long periods of time in bed, clotting disorders that are either congenital or acquired due to smoking, hormonal treatments, and some medications. DVT's can also happen spontaneously but this is very rare. Clots can also occur in the surface or superficial veins around the skin and is called phlebitis (NOT A DVT) and is not dangerous but often painful. These superficial colts are very small and do not travel in the veins. Bulging varicose veins often have sluggish and turbulent flow which can lead to phlebitis and is also easily prevented by treating the varicose veins.

If you have large varicosities, clots can indeed form in these superficial veins. Inflammation and pain are frequently associated. This condition is called "superficial thrombophlebitis". These thrombi, are usually densely adhered to the vein wall, and seldom break off. They have the potential to grow and migrate into the deep system when they develop close to a communicating vein that connects the superficial and deep systems. When this happens, they are at risk for migrating or braking away and lodging into the pulmonary circulation. This condition can be life threatening and is known as "pulmonary embolism" or PE.

A variety of factors can lead to DVT. The Risk of DVT increases with age and smoking. There are also may be inherited blood disorders that increase risk for DVT . Women who are pregnant or who are taking birth control pills or hormone replacements also have an increased risk of developing deep vein thrombosis. Certain medical conditions, such as cancer, obesity, heart failure, and surgery increase the risk of forming a blood clot. These conditions/factors make the blood more sticky. They combine with other factors such as, bed rest, long-distance travel and restricted mobility to make the blood more static or not flow well. Varicose veins are another factor that impedes flow and makes blood more likely to clot. Varicose veins can, on occasion clot themselves and that is called superficial phlebitis. Superficial phlebitis is not a life threatening condition , however in a small percentage , 10-20% of the time superficial phlebitis is associated with a deep vein phlebitis or DVT. However, keep in mind that the overall risk of DVT from varicose veins is very small.

There are lots of reasons that relate to blood clot formation. Clots in your varicose veins may become inflamed and cause phlebitis. Clots in varicose veins can pass to the deeper system causing more significant and dangerous problems. A full venous evaluation can help you with treating and caring for your venous disease.

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