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Deep vein thrombosis (DVT)

Overview

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 also can occur with no symptoms.

Deep vein thrombosis can develop if you have certain medical conditions that affect how your blood clots. It can also happen if you don't move for a long time, such as after surgery or an accident, or when you're confined to bed.

Deep vein thrombosis can be very serious because blood clots in your veins can break loose, travel through your bloodstream and lodge in your lungs, blocking blood flow (pulmonary embolism).

Blood clot in leg vein

A blood clot in a leg vein may cause pain, warmth and tenderness in the affected area.

Symptoms

Deep vein thrombosis signs and symptoms can include:

Swelling in the affected leg. Rarely, there's swelling in both legs.

  • Pain in your leg. The pain often starts in your calf and can feel like cramping or soreness.
  • Red or discolored skin on the leg.
  • A feeling of warmth in the affected leg.

Deep vein thrombosis can occur without noticeable symptoms.

When to see a doctor

If you develop signs or symptoms of deep vein thrombosis, contact your doctor.

If you develop signs or symptoms of a pulmonary embolism — a life-threatening complication of deep vein thrombosis — seek immediate medical attention.

The warning signs and symptoms of a pulmonary embolism include:

  • Sudden shortness of breath
  • Chest pain or discomfort that worsens when you take a deep breath or when you cough
  • Feeling lightheaded or dizzy, or fainting
  • Rapid pulse
  • Coughing up blood

Causes

The blood clots of deep vein thrombosis can be caused by anything that prevents your blood from circulating or clotting normally, such as injury to a vein, surgery, certain medications and limited movement.

Risk factors

Many factors can increase your risk of developing deep vein thrombosis (DVT). The more you have, the greater your risk of DVT. Risk factors include:

  • Inheriting a blood-clotting disorder. Some people inherit a disorder that makes their blood clot more easily. This condition on its own might not cause blood clots 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 (oral contraceptives) or 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 substances in your blood that cause your blood to clot. Some forms of cancer treatment also increase the risk of blood clots.
  • Heart failure. This increases your risk of DVT and pulmonary embolism. Because people with heart failure 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. If you or someone in your family has had one or both of these, you might be at greater risk of developing a DVT.
  • Age. Being older than 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 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 don't move for long periods.

Complications

A serious complication associated with deep vein thrombosis is pulmonary embolism.

Pulmonary embolism

A pulmonary embolism occurs when a blood vessel in your lung becomes blocked by a blood clot (thrombus) that travels to your lung from another part of your body, usually your leg.

A pulmonary embolism can be life-threatening. It's important to watch for signs and symptoms of a pulmonary embolism and seek medical attention if they occur. Signs and symptoms of a pulmonary embolism include:

  • Sudden shortness of breath
  • Chest pain or discomfort that worsens when you take a deep breath or when you cough
  • Feeling lightheaded or dizzy, or fainting
  • Rapid pulse
  • Coughing up blood

Postphlebitic syndrome

A common complication that can occur after deep vein thrombosis is known as postphlebitic syndrome, also called postthrombotic syndrome. Damage to your veins from the blood clot reduces blood flow in the affected areas, which can cause:

  • Persistent swelling of your legs (edema)
  • Leg pain
  • Skin discoloration
  • Skin sores
Pulmonary embolism

Pulmonary embolism occurs when a blood clot gets lodged in an artery in the lung, blocking blood flow to part of the lung. Blood clots most often originate in the legs and travel up through the right side of the heart and into the lungs.

Diagnosis

To diagnose deep vein thrombosis, your doctor will ask you about your symptoms. You'll also have a physical exam so that your doctor can check for areas of swelling, tenderness or discoloration on your skin. Depending on how likely you are to have a blood clot, your doctor might suggest tests, including:

  • Ultrasound. A wandlike 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 might be visible in the image.

    Sometimes a series of ultrasounds are done over several days to determine whether a blood clot is growing or to check for a new one.

  • Blood test. Almost all people who develop severe deep vein thrombosis have an elevated blood level of a substance called D dimer.
  • Venography. A dye is injected into a large vein in your foot or ankle. An X-ray creates an image of the veins in your legs and feet, to look for clots. However, less invasive methods of diagnosis, such as ultrasound, can usually confirm the diagnosis.
  • CT or MRI scans. Either can provide visual images of your veins and might show if you have a clot. Sometimes these scans performed for other reasons reveal a clot.

Treatment

Deep vein thrombosis (DVT) treatment is aimed at preventing the clot from getting bigger and preventing it from breaking loose and causing a pulmonary embolism. Then the goal becomes reducing your chances of deep vein thrombosis happening again.

Deep vein thrombosis treatment options include:

  • Blood thinners. Deep vein thrombosis is most commonly treated with anticoagulants, also called blood thinners. These drugs, which can be injected or taken as pills, decrease your blood's ability to clot. They don't break up existing blood clots, but they can prevent clots from getting bigger and reduce your risk of developing more clots.

    The injectable medications can be given as a shot under the skin or by injection into your arm vein (intravenous).

    Heparin is typically given intravenously. Other similar blood thinners, such as enoxaparin (Lovenox), dalteparin (Fragmin) or fondaparinux (Arixtra), are injected under the skin.

    You might receive an injectable blood thinner for a few days, after which pills such as warfarin (Coumadin, Jantoven) or dabigatran (Pradaxa) are started. Once warfarin has thinned your blood, the injectable blood thinners are stopped.

    Other blood thinners can be given in pill form without the need for an injectable blood thinner. These include rivaroxaban (Xarelto), apixaban (Eliquis) or edoxaban (Savaysa).

    You might need to take blood thinner pills for three months or longer. It's important to take them exactly as your doctor instructs because taking too much or too little can cause serious side effects.

    If you take warfarin, you'll need periodic blood tests to check how long it takes your blood to clot. Pregnant women shouldn't take certain blood-thinning medications.

  • Clot busters. If you have a more serious type of deep vein thrombosis or pulmonary embolism, or if other medications aren't working, your doctor might prescribe drugs that break up clots quickly, called clot busters or thrombolytics.

    These drugs are either given through an IV line to break up blood clots or through a catheter placed directly into the clot. These drugs can cause serious bleeding, so they're generally reserved for severe cases of blood clots.

  • Filters. If you can't take medicines to thin your blood, you might have a filter 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. To help prevent swelling associated with deep vein thrombosis, these 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. You should wear these stockings during the day for at least two years, if possible.

Support stockings

Compression stockings, also called support stockings, compress your legs, promoting circulation. A stocking butler may help you put on the stockings.

Preparing for an appointment

Deep vein thrombosis (DVT) is considered a medical emergency, so it's important to get evaluated quickly. However, if you have time before your appointment, here's some information to help you get ready.

What you can do

Make a list of:

  • Your symptoms, including any that seem unrelated to deep vein thrombosis, and when they began
  • Key personal information, including if you have a family history of blood-clotting disorders, and whether you have been hospitalized, or have had illnesses, surgery or trauma in the past three months, or have been traveling
  • All medications, vitamins or other supplements you take, including doses
  • Questions to ask your doctor

Take a family member or friend along, if possible, to help you remember the information you're given.

For deep vein thrombosis, questions to ask your doctor include:

  • What's the most likely cause of my symptoms?
  • What tests do I need?
  • What's the best treatment?
  • What are the alternatives to the primary approach that you're suggesting?
  • Will I need to restrict my physical activity or travel?
  • I have other health conditions. How can I best manage these conditions together?
  • Are there brochures or other printed material I can have? What websites do you recommend?

What to expect from your doctor

Your doctor is likely to ask you questions, such as:

  • Have you been inactive lately, such as sitting or lying down for long periods?
  • Do your symptoms bother you all the time, or do they come and go?
  • How severe are your symptoms?
  • What, if anything, makes your symptoms improve?
  • Does anything worsen your symptoms?

Lifestyle and home remedies

Once you receive treatment for deep vein thrombosis (DVT), you need to watch your diet and watch for signs of excessive bleeding, as well as take steps to prevent another DVT. Some things you can do include:

  • Check in with your doctor regularly to see if your treatment needs 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 for excessive bleeding, which can be a side effect of taking 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.

Prevention

Measures to prevent deep vein thrombosis include:

  • Avoid sitting still. If you have 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, don't cross your legs, which can hamper 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, stand or walk occasionally. If you can't do that, exercise your lower legs. Try raising and lowering your heels while keeping your toes on the floor, then raising your toes with your heels are on the floor.

  • Make lifestyle changes. Lose weight and quit smoking.
  • Exercise. Regular exercise lowers your risk of blood clots, which is especially important for people who sit a lot or travel frequently.

Last updated: July 12th, 2017

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