What Is Deep Vein Thrombosis?

Deep vein thrombosis (throm-BO-sis), or DVT, is a blood clot that forms in a vein deep in the body. Blood clots occur when blood thickens and clumps together.

Most deep vein blood clots occur in the lower leg or thigh. They also can occur in other parts of the body.

A blood clot in a deep vein can break off and travel through the bloodstream. The loose clot is called an embolus (EM-bo-lus). It can travel to an artery in the lungs and block blood flow. This condition is called pulmonary embolism (PULL-mun-ary EM-bo-lizm), or PE.

PE is a very serious condition. It can damage the lungs and other organs in the body and cause death.

Blood clots in the thighs are more likely to break off and cause PE than blood clots in the lower legs or other parts of the body. Blood clots also can form in veins

What Are the Signs and Symptoms of Deep Vein Thrombosis?

The signs and symptoms of deep vein thrombosis (DVT) might be related to DVT itself or pulmonary embolism (PE). See your doctor right away if you have signs or symptoms of either condition. Both DVT and PE can cause serious, possibly life-threatening problems if not treated.

Deep Vein Thrombosis Signs and Symptoms

Only about half of the people who have DVT have signs and symptoms. These signs and symptoms occur in the leg affected by the deep vein clot. They include:

  • Swelling of the leg or along a vein in the leg 
  • Pain or tenderness in the leg, which you may feel only when standing or walking
  • Increased warmth in the area of the leg that's swollen or painful
  • Red or discolored skin on the leg

Pulmonary Embolism Signs and Symptoms

Some people aren't aware of a deep vein clot until they have signs and symptoms of PE. Signs and symptoms of PE include:

  • Unexplained shortness of breath
  • Pain with deep breathing
  • Coughing up blood
  • Rapid breathing and a fast heart rate also may be signs of PE.

How Is Deep Vein Thrombosis Treated?

Doctors treat deep vein thrombosis (DVT) with medicines and other devices and therapies. The main goals of treating DVT are to:

  • Stop the blood clot from getting bigger
  • Prevent the blood clot from breaking off and moving to your lungs
  • Reduce your chance of having another blood clot

Anticoagulants

Anticoagulants (AN-te-ko-AG-u-lants) are the most common medicines for treating DVT. They're also known as blood thinners.

These medicines decrease your blood's ability to clot. They also stop existing blood clots from getting bigger. However, blood thinners can't break up blood clots that have already formed. (The body dissolves most blood clots with time.)

Blood thinners can be taken as a pill, an injection under the skin, or through a needle or tube inserted into a vein (called intravenous, or IV, injection).

Warfarin and heparin are two blood thinners used to treat DVT. Warfarin is given in pill form. (Coumadin® is a common brand name for warfarin.) Heparin is given as an injection or through an IV tube. There are different types of heparin. Your doctor will discuss the options with you.

Your doctor may treat you with both heparin and warfarin 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 usually are treated with just heparin because warfarin is dangerous during pregnancy.

Treatment for DVT using blood thinners usually lasts for 6 months. The following situations may change the length of treatment:

  • If your blood clot occurred after a short-term risk (for example, surgery), your treatment time may be shorter.
  • If you've had blood clots before, your treatment time may be longer.
  • If you have certain other illnesses, such as cancer, you may need to take blood thinners for as long as you have the illness.

The most common side effect of blood thinners is bleeding. Bleeding can happen if the medicine thins your blood too much. This side effect can be life threatening.

Sometimes the bleeding is internal (inside your body). People treated with blood thinners usually have regular blood tests to measure their blood's ability to clot. These tests are called PT and PTT tests.

These tests also help your doctor make sure you're taking the right amount of medicine. Call your doctor right away if you have easy bruising or bleeding. These may be signs that your medicines have thinned your blood too much.

Thrombin Inhibitors

These medicines interfere with the blood clotting process. They're used to treat blood clots in patients who can't take heparin.

Thrombolytics

Doctors prescribe these medicines to quickly dissolve large blood clots that cause severe symptoms. Because thrombolytics can cause sudden bleeding, they're used only in life-threatening situations.

Vena Cava Filter

If you can't take blood thinners or they're not working well, your doctor may recommend a vena cava filter.

The filter is inserted inside a large vein called the vena cava. The filter catches blood clots before they travel to the lungs, which prevents pulmonary embolism. However, the filter doesn't stop new blood clots from forming.

Graduated Compression Stockings

  • Graduated compression stockings can reduce leg swelling caused by a blood clot. These stockings are worn on the legs from the arch of the foot to just above or below the knee.
  • Compression stockings are tight at the ankle and become looser as they go up the leg. This creates gentle pressure up the leg. The pressure keeps blood from pooling and clotting.
  • There are three types of compression stockings. One type is support pantyhose, which offer the least amount of pressure.
  • The second type is over-the-counter compression hose. These stockings give a little more pressure than support pantyhose. Over-the-counter compression hose are sold in medical supply stores and pharmacies.
  • Prescription-strength compression hose offer the greatest amount of pressure. They also are sold in medical supply stores and pharmacies. However, a specially trained person needs to fit you for these stockings.