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Deep Vein Thrombosis

Knowing the early warning signs of deep vein thrombosis can help stop it from becoming a medical emergency.
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Last updated July 11, 2024

Deep vein thrombosis quiz

Take a quiz to find out if you have deep vein thrombosis.

What it is

Deep vein thrombosis (DVT) is a blood clot in a vein. While it can occur anywhere, it is most often in the lower legs. It usually causes pain and swelling.

The clot may form after damage or a decrease in blood flow in the vein. Though certain medical conditions and inherited clotting disorders increase the risk. The most dangerous complication of a DVT is a pulmonary embolism (PE). This happens when the clot breaks off and travels to the lung where it causes a blockage.

A blood clot in a leg vein cuts off blood flow and causes inflammation.

What are the warning signs of deep vein thrombosis?

The most common signs or symptoms are pain and swelling at the location of the clot.

Inherited clotting disorders, along with previous DVT or PE or family history of DVT or PE, can increase your risk. The more risk factors you have, the more likely you are to develop a DVT.

Main symptoms

Pro Tip

DVT puts you at an increased risk of developing a pulmonary embolism (PE).  A PE occurs when the blood clot travels to the lungs. The most common symptoms are difficulty breathing and sharp chest pain that's worse when inhaling.  A pulmonary embolism is a medical emergency. —Dr. Chandra Manuelpillai

  • Pain
  • Swelling

Other symptoms you may have

  • Red discoloration
  • Warm to touch
  • Enlarged vein that you can feel—it may hurt
  • Difficulty breathing, chest pain, and coughing up blood are some of the symptoms of a pulmonary embolism

How do you get deep vein thrombosis?

Blood clots can form inside a vein after it’s been damaged. Or the blood flow through the vein has decreased. Veins get damaged by trauma (like from an accident) or after using a catheter (a tube inserted into a vein to deliver fluids or medications).

Blood flow decreases when you are not moving around. So risk of blood clots increases during long trips—especially flying—long-term sitting in one position, paralysis, hospitalization, or surgery. It is more common in people who require bed rest or a cast.

There’s a higher risk of DVT in women on hormonal birth control or hormonal replacement therapy. It can also happen during pregnancy—and up to 3 months after giving birth.

Certain medical problems may also increase your risk. These include heart disease, lung disease, cancer, and inflammatory bowel disease (Crohn's and ulcerative colitis). Along with older age (over 50 years old), obesity, and tobacco smoking.

Dr. Rx

For a long car trip, plan frequent stops to move around and get blood flowing in your legs. During a long plane ride, walk the aisles. Move your legs while seated by pumping your feet and doing exercises that repeatedly contract your muscles. —Dr. Manuelpillai

Can a DVT go away on its own?

A DVT needs to be treated. Treatment is often based on the size and location of your DVT. Along with underlying medical conditions and what is believed to be the cause. Treatment will be for at least 3 months.

  • Anticoagulants (blood thinners like warfarin) are medications that help prevent clots from forming.
  • Thrombolytics are drugs that help dissolve clots.
  • Thrombectomy is a surgical procedure that removes the clot.
  • An IVC filter is implanted surgically to prevent blood clots that break off and cause a pulmonary embolism. IVC is the inferior vena cava—a large central vein that brings blood from the lower body back to lungs and heart.

Is deep vein thrombosis an emergency?

If you think you have DVT or blood clot, contact your doctor or go to urgent care. You may want to request an outpatient ultrasound. You should go to the ER if you also have difficulty breathing, chest pain (especially when breathing deeply), or coughing up blood. These may be signs of a blood clot in the lungs.

If you are on anticoagulants, be extra careful about getting injured, including bruising. These medications make it harder for your blood to clot, so you are more likely to bleed while on these medications. Depending on where the bleeding is, it could be life-threatening.

Follow up

Pro Tip

Discuss with your doctor if additional testing or referral to a specialist is necessary to determine if there are any underlying risk factors that you are not aware of.  Once you know your risk factors, discuss which treatments are best for you and what lifestyle changes are needed. —Dr. Manuelpillai

Once you have had a DVT, you are at an increased risk of developing another one. Discuss with your primary care physician when you should be checked again. The doctor may request another imaging test to confirm you no longer have a clot. You may also need a referral to a specialist like a hematologist (specialist for diseases related to blood).

Also, some anticoagulants require frequent blood tests and dose adjustments to ensure you are in the proper therapeutic range. Your doctor should be able to arrange this.

Post-thrombotic syndrome or post-phlebitic syndrome occurs when the blood clot damages the valves in the vein. This leads to chronic decreased blood flow. And can result in chronic swelling and pain, as well as eventual chronic skin changes including discoloration and ulcers.


Preventing DVT depends on the underlying cause. Ways to prevent decreased blood flow in the vein include frequently moving around, especially after sitting in one position and wearing compression stockings. Lifestyle changes may also help including staying active, losing weight, and not smoking.

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Once your story receives approval from our editors, it will exist on Buoy as a helpful resource for others who may experience something similar.
The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Dr. Le obtained his MD from Harvard Medical School and his BA from Harvard College. Before Buoy, his research focused on glioblastoma, a deadly form of brain cancer. Outside of work, Dr. Le enjoys cooking and struggling to run up-and-down the floor in an adult basketball league.

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