deep vein thrombosis
Credit and © Society of Interventional Radiology.
Deep vein thrombosis is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or thigh. They also can occur in other parts of the body.
If a clot in a vein breaks off and travels through the bloodstream, it can lodge in one of the lungs. This is called pulmonary embolism, which is a very serious condition that can cause death. Blood clots in the thigh are usually more likely to break off and cause pulmonary embolism than clots in the lower leg or other parts of the body.
A blood clot also can occur in veins that are close to the surface of the skin. This type of blood clot is called superficial venous thrombosis or phlebitis. Blood clots in superficial veins are not dangerous because they can't travel to the lungs.
Who is at risk for deep vein thrombosis?
Many factors may increase your risk for deep vein thrombosis:
The risk for deep vein clots increases if a person who has several risk factors at the same time. For example, a woman with an inherited condition for clotting who also takes birth control pills has an even higher risk to have a blood clot.
Signs and symptoms
It is important to see a doctor right away if symptoms of deep vein thrombosis or pulmonary embolism appear. Deep vein thrombosis can cause very serious complications if not treated.
Deep vein thrombosis
Only about half of the people with deep vein thrombosis have symptoms. The symptoms may include:
Some people find out that they have deep vein thrombosis only after the clot has moved from the leg and traveled to the lung (pulmonary embolism). The symptoms may include:
A doctor will obtain a medical history and carry out an examination in order to determine if a person has deep vein thrombosis.
Commonly used tests
Less frequently used tests
If an inherited blood clotting disorder is suspected, tests may be run for it. The presence of an inherited clotting disorder is suggested by:
The main goals in treating deep vein thrombosis are to:
Several types of medicine may be used to treat and/or prevent deep vein thrombosis:
Anticoagulants can be taken as either a pill (warfarin) or an injection (heparin).
A doctor may treat a patient with both heparin and warfarin (Coumadin) at the same time. Heparin acts quickly. Warfarin takes 2 to 3 days before it starts to work. Once the warfarin starts to work, the heparin is stopped.
Pregnant women can't take warfarin and are treated with heparin only.
Treatment for deep vein thrombosis with anticoagulants usually lasts from 3 to 6 months. However, the following situations may change the length of treatment:
- If the blood clot occurred after a short-term risk (for example, surgery), the treatment may be shorter.
- In patients who have had clots before, a longer treatment will be needed.
- In patients who have certain other illnesses, such as cancer, they may need to take anticoagulants for as long as the illness is present.
The most common side effect of anticoagulants is bleeding. A doctor should be informed right away by patients who are taking warfarin or heparin and have easy bruising or bleeding. Blood tests can check how well the medicine is working.
Vena cava filters are used when a patient can't take medicines to thin the blood, or when they are taking blood thinners but continue to develop clots anyway. The filter is inserted inside a large vein called the vena cava. The filter catches clots that break off in a vein before they move through the bloodstream to the lungs (pulmonary embolism). The filter doesn't prevent new clots from developing. Graduated dvt compression stockings can reduce the chronic swelling that can occur after a blood clot has developed in a leg. The leg swelling is due to damage to the valves in the leg veins. Graduated compression stockings are worn on the legs from the arch of the foot to just above or below the knee. These stockings are tight at the ankle and become looser as they go up the leg. This causes a gentle compression (or pressure) up the leg. The pressure keeps blood from pooling and clotting.
Some drawbacks of wearing the stockings are:
Much of the treatment for deep vein thrombosis takes place at home. It is important to:
Preventing deep vein thrombosis depends on whether a person has had a clot before and on risk factors for developing a clot.
If a deep vein clot has developed before, future clots may be prevented by:
In the cases where a person has not had a deep vein clot before but has risks factors for developing one, it may be possible to prevent a clot by: