Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins in your body, usually in your legs. Deep vein thrombosis can cause leg pain or swelling, but may occur without any symptoms. Deep vein thrombosis can develop if you have certain medical conditions that affect how your blood clots. Deep vein thrombosis can also happen if you don't move for a long time, such as after surgery, following an accident, or when you are confined to a hospital or nursing home bed. Deep vein thrombosis is a serious condition because blood clots in your veins can break loose, travel through your bloodstream and lodge in your lungs, blocking blood flow (pulmonary embolism).
Deep vein thrombosis signs and symptoms can include:
- Swelling in the leg
- Red or discolored skin
- Warmth in the skin
- Pain in the calf
- Chest pain
- Shortness of breath
- Coughing up blood
- Rapid or irregular heart beat
Deep vein thrombosis occurs when a blood clot forms in the veins that are deep in your body, often in your legs. Blood clots can be caused by anything that prevents your blood from circulating normally or clotting properly.
Many factors can increase your risk of developing deep vein thrombosis (DVT), and the more you have, the greater your risk. Risk factors for DVT include:
- Inheriting a blood-clotting disorder. Some people inherit a disorder that makes their blood clot more easily. This inherited condition may not cause problems unless combined with one or more other risk factors.
- Prolonged bed rest, such as during a long hospital stay, or paralysis. When your legs remain still for long periods, your calf muscles don't contract to help blood circulate, which can increase the risk of blood clots.
- Injury or surgery. Injury to your veins or surgery can increase the risk of blood clots.
- Pregnancy. Pregnancy increases the pressure in the veins in your pelvis and legs. Women with an inherited clotting disorder are especially at risk. The risk of blood clots from pregnancy can continue for up to six weeks after you have your baby.
- Birth control pills or hormone replacement therapy. Birth control pills (oral contraceptives) and hormone replacement therapy both can increase your blood's ability to clot.
- Being overweight or obese. Being overweight increases the pressure in the veins in your pelvis and legs.
- Smoking. Smoking affects blood clotting and circulation, which can increase your risk of DVT.
- Cancer. Some forms of cancer increase the amount of substances in your blood that cause your blood to clot. Some forms of cancer treatment also increase the risk of blood clots.
- Heart failure. People with heart failure have a greater risk of DVT and pulmonary embolism. Because people with heart failure already have limited heart and lung function, the symptoms caused by even a small pulmonary embolism are more noticeable.
- Inflammatory bowel disease. Bowel diseases, such as Crohn's disease or ulcerative colitis, increase the risk of DVT.
- A personal or family history of deep vein thrombosis or pulmonary embolism (PE). If you or someone in your family has had DVT or PE before, you're more likely to develop DVT.
- Age. Being over age 60 increases your risk of DVT, though it can occur at any age.
- Sitting for long periods of time, such as when driving or flying. When your legs remain still for many hours, your calf muscles don't contract, which normally helps blood circulate. Blood clots can form in the calves of your legs if your calf muscles aren't moving for long periods.
To diagnose deep vein thrombosis, your doctor will ask you a series of questions about your symptoms. You'll also have a physical exam so that your doctor can check for any areas of swelling, tenderness or discoloration on your skin. Depending on how likely you are to have a blood clot, your doctor may suggest further testing, including:
- Ultrasound. A wand-like device (transducer) placed over the part of your body where there's a clot sends sound waves into the area. As the sound waves travel through your tissue and reflect back, a computer transforms the waves into a moving image on a video screen. A clot may be visible in the image.
- Blood test.
- CT or MRI scans. Both computerized tomography (CT) scan and magnetic resonance imaging (MRI) can provide visual images of your veins and may show if you have a clot. Sometimes a clot is found when these scans are performed for other reasons.
Deep vein thrombosis treatment is aimed at preventing the clot from getting any bigger, as well as preventing the clot from breaking loose and causing a pulmonary embolism. After that, the goal becomes reducing your chances of deep vein thrombosis happening again. Deep vein thrombosis treatment options include:
- Blood thinners. Medications used to treat deep vein thrombosis include the use of anticoagulants, also sometimes called blood thinners, whenever possible. These are drugs that decrease your blood's ability to clot. While they don't break up existing blood clots, they can prevent clots from getting bigger or reduce your risk of developing additional clots. Usually, you'll first be given a shot or infusion of the blood thinner heparin for a few days. After starting heparin injections, your treatment may be followed by another injectable blood thinner, such as enoxaparin (Lovenox), dalteparin (Fragmin) or fondaparinux (Arixtra). Other blood thinners can be given in pill form, such as warfarin (Coumadin, Jantoven) or rivaroxaban (Xarelto). Newer blood thinners also may offer additional options in the near future. You may need to take blood thinners for three months or longer. If you're prescribed any of these blood thinners, it's important to take your medication exactly as your doctor instructs. Blood-thinning medications can have serious side effects if you take too much or too little. You may need periodic blood tests to check how long it takes your blood to clot. Pregnant women shouldn't take certain blood-thinning medications.
- Clotbusters. If you have a more serious type of deep vein thrombosis or pulmonary embolism, or if other medications aren't working, your doctor may prescribe different medications. One group of medications is known as thrombolytics. These drugs, called tissue plasminogen activators (TPA), are given through an IV line to break up blood clots or may be given through a catheter placed directly into the clot. These drugs can cause serious bleeding and are generally used only in life-threatening situations. For these reasons, thrombolytic medications are only given in an intensive care ward of a hospital.
- Filters. If you can't take medicines to thin your blood, a filter may be inserted into a large vein — the vena cava — in your abdomen. A vena cava filter prevents clots that break loose from lodging in your lungs.
- Compression stockings. These help prevent swelling associated with deep vein thrombosis. These stockings are worn on your legs from your feet to about the level of your knees. This pressure helps reduce the chances that your blood will pool and clot. Compression stockings can help prevent postphlebitic syndrome.
- Check in with your doctor regularly to see if your medication or treatments need to be modified. If you're taking warfarin (Coumadin, Jantoven), you'll need a blood test to see how well your blood is clotting.
- Take your blood thinners as directed. If you've had DVT, you'll be on blood thinners for at least three to six months.
- Watch how much vitamin K you're eating if you are taking warfarin. Vitamin K can affect how warfarin works. Green leafy vegetables are high in vitamin K. Check with your doctor or a dietitian about your diet if you're taking warfarin.
- Be on the lookout for excessive bleeding, which can be a side effect of taking medications such as blood thinners. Talk to your doctor about activities that could cause you to bruise or get cut, as even a minor injury could become serious if you're taking blood thinners.
- Move. If you've been on bed rest, because of surgery or other factors, the sooner you get moving, the less likely blood clots will develop.
- Wear compression stockings to help prevent blood clots in the legs if your doctor recommends them.
To prevent deep vein thrombosis, some common preventive measures include the following:
- Take any prescribed medications as directed. If you're having surgery, such as orthopedic surgery, you'll probably be given blood thinners while you're in the hospital. Your doctor may also prescribe aspirin or other medications that help prevent clots to be taken for a while after surgery.
- Avoid sitting still. If you've had surgery or have been on bed rest for other reasons, try to get moving as soon as possible. If you're sitting for a while, try not to cross your legs because this can limit blood flow. If you're traveling a long distance by car, stop every hour or so and walk around. If you're on a plane, try to stand or walk occasionally. If you can't do that, at least try to exercise your lower legs. Try raising and lowering your heels while keeping your toes on the floor, then raising your toes while your heels are on the floor.
- Make lifestyle changes. Lose weight and quit smoking. Obesity and smoking increase your risk of deep vein thrombosis.
- Get regular exercise. Exercise lowers your risk of blood clots, which is especially important for people who have to sit a lot or travel frequently.