What is deep vein thrombosis?
Deep vein thrombosis (DVT) is a blood clot that usually forms in deep veins of the arms or legs. But these clots can also occur in other parts of the body. DVT can occur when blood clumps and thickens to block the flow of blood. This can cause life-threatening complications if a piece of the clot breaks off and travels through the heart and into the pulmonary arteries. There the blood clot can lodge in the lungs and form a pulmonary embolism, which can be fatal if the clot is large enough.
What are the symptoms of DVT?
Only about half of people suffering from DVT experience the following classic symptoms, but not all need be present:
- Swelling in the leg or along a vein
- Pain or tenderness in the leg felt on standing or walking
- Increased warmth at the area of pain and swelling
- Redness of the skin in the affected area
What are the risk factors for DVT?
- Previous history of DVT
- Conditions that thicken the blood
- Hormone therapy or birth control pills
- Slow blood flow in a deep vein after surgery because of a lack of movement
- Pregnancy and the first six weeks after giving birth
- Recent or ongoing treatment of cancer
- Placement of a catheter, or tube, in a vein for medical treatment
- Being older than age 60 (although DVT can happen at any age)
- Being overweight or obese
How is DVT diagnosed?
DVT is diagnosed based on medical history, a physical exam and diagnostic test results.
Ultrasound is the most common test doctors use to diagnose DVT. This test shows blood flow through the arteries and veins of the affected leg. If the ultrasound doesn’t allow a clear diagnosis, your physician may order a venography or a D-dimer test. For a venography, dye is injected into a vein in the affected leg to show on an X-ray machine whether blood flow there is slow. A D-dimer test checks for levels of a substance released into the blood when a clot dissolves. If levels of the substance are high, there may be a DVT present.
Other tests to diagnose deep vein thrombosis include MRI or CT scanning and blood tests.
What are the treatment options for DVT?
The goals of DVT therapy are to reduce the chance of developing another blood clot, stop the clot from getting bigger and prevent blood clots from breaking off and traveling to the lung. Generally, doctors treat deep vein thrombosis with medicines called anticoagulants that thin the blood by reducing its ability to thicken and form clots. These medicines are administered orally in pill form (warfarin), as an injection under the skin or through a vein via intravenous (IV) injection (heparin).
For patients who can’t take heparin, doctors use thrombin inhibitors, medicines that stop blood from clotting. In addition, meds called thrombolytics can be prescribed to dissolve large and dangerous blood clots. But these drugs are used only in life-threatening situations as they can cause sudden bleeding.
Last Reviewed: August 8, 2018