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Deep Vein Thrombosis: Causes, Prevention, and Treatment

Deep Vein Thrombosis: Causes, Prevention, and Treatment

What Is Deep Vein Thrombosis?

Deep vein thrombosis (DVT) occurs when a blood clot forms in the deep veins, usually in the legs. In some cases, it can also occur in the veins of the arms, cerebral veins, and mesenteric veins located in the abdomen. It usually affects areas with decreased or altered blood flow.

If left untreated, blood clots may travel through the bloodstream and become a source of dangerous complications. It is one of the most common causes of death worldwide. However, it is preventable, and there are treatments available.


There are cases where symptoms of deep vein thrombosis do not occur, or may occur but are not too noticeable. Symptoms include the following:

  • Extreme pain and swelling in one leg, but can also occur in both legs. The pain usually starts from the calf, with the feeling of cramps and soreness
  • May feel warmth in the affected leg
  • There may be redness or discoloration of the skin in the leg

If deep vein thrombosis is left untreated for a long time, it may lead to pulmonary embolism. These are the symptoms to watch out for:

  • Sudden difficulty in breathing
  • Chest pains that worsen when breathing or coughing
  • Feeling dizzy, fainting
  • Rapid breathing and pulse

Seek medical attention if you develop any of these symptoms.

Causes and Risk Factors

In general, any situation that blocks the blood flow in the body may cause a blood clot. Deep vein thrombosis is at higher risk of occurring in the following situations:

  • Trauma and Surgery. Physical injury, injury in the veins due to surgery, or surgery alone may cause or increase the risk of forming blood clots.
  • Malignancy. Cancer cells and cancerous tumors pressure veins that cause the development of blood clots.
  • Prolonged Immobility. It refers to a long time of being unable to move due to sleeping, bed rest from surgery, long flights, sitting, stroke, and paralysis.
  • Increased pressure in the veins. Pregnancy and stenosis can increase pressure in the veins. Pregnant women can still have deep vein thrombosis six months after birth.
  • Heart Failure. It increases the risk of deep vein thrombosis and further complications, such as pulmonary embolism. The symptoms of people with heart failure are more evident.
  • Obesity. The body fat contributes to heavy pressure in the veins on the legs.
  • Age. People ages 60 and older are at risk of DVT.
  • History. People with a personal or family history of DVT have more risk of developing it.
  • Smoking. It damages blood circulation and increases the risk of forming a blood clot.

Pulmonary Embolism: The Danger of Blood Clots


Pulmonary Embolism

This is the most common complication of DVT and creates a higher risk of death in patients. It happens when the blood clot from the leg travels up to the lungs, blocking the blood vessels.

Post-Thrombotic Syndrome

This is the condition wherein the leg becomes damaged and fails to function well. This may occur a few weeks or up to two years after someone has DVT.


The following measures help prevent DVT:

  • Move around. If you are capable of moving around, do not sit still for a long time. If sitting, avoid crossing legs as it may block the blood flow.
  • Exercise. Manage weight by exercising. It is also helpful for people to avoid staying still or sitting in one place for a long time.
  • Do not smoke. A study concludes that smoking can increase the risk of having deep vein thrombosis as it may affect the blood circulation in the body.


These are the following diagnostic tests that doctors use to diagnose DVT:

  • Physical exam
  • Blood Test. A D-dimer blood test is for measuring the protein level produced by blood clots. If the protein level is within normal measures, there is a reduced risk of pulmonary embolism.
  • Ultrasound. This creates an image showing the blood flow through the veins. For several days, doctors may monitor new possible blood clots and growths of existing ones through ultrasound.
  • Venography. This is an x-ray for the legs. Imaging of the veins is done to find blood clots.
  • Magnetic Resonance Imaging (MRI). This is for finding blood clots in the abdomen.


The following treatments for DVT aim to prevent blood clots from growing, traveling to the lungs, and prevent recurrence of the condition:

  • Blood thinners. These reduce the chance of blood clots expanding, and the likelihood of developing new ones. This treatment may come as injections or pills.
  • Clot busters. This may be used if medication does not lead to improvements. However, it is only for people with severe deep vein thrombosis or pulmonary embolism. Clot busters work by placing a tube or catheter directly on the blood clot. Heavy bleeding may occur during the process.
  • Filters. This is the insertion of filters in the vena cava in the abdomen. It prevents loose blood clot from traveling to the lungs.

Key Takeaway

Deep vein thrombosis or DVT is a preventable and manageable condition. It occurs due to blood clots, which may form when one stays still in one place for a long time. There are treatments available to prevent the clots from getting bigger and expanding to other internal organs. If left untreated, DVT may cause severe complications that may lead to death. Avoid the formation of blood clots by moving around and exercising.

Learn about Other Blood Disorders here.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Current and Former Smoking and Risk for Venous Thromboembolism: A Systematic Review and Meta-Analysis, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3775725/

Accessed April 19, 2021


Deep vein thrombosis (DVT), https://www.mayoclinic.org/diseases-conditions/deep-vein-thrombosis/symptoms-causes/syc-20352557

Accessed April 19, 2021


Deep vein thrombosis (DVT), https://www.mayoclinic.org/diseases-conditions/deep-vein-thrombosis/diagnosis-treatment/drc-20352563

Accessed April 19, 2021


Deep vein thrombosis: pathogenesis, diagnosis, and medical management, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5778510/

Accessed April 19, 2021


Deep Vein Thrombosis, https://www.ncbi.nlm.nih.gov/books/NBK507708/

Accessed April 19, 2021


Venous Thromboembolism (Blood Clots), https://www.cdc.gov/ncbddd/dvt/facts.html

Accessed April 19, 2021


Blood Clots (Deep Vein Thrombosis) and Cancer, https://www.mskcc.org/cancer-care/types/benign-blood-disorders/blood-clotting-thrombosis

Accessed April 19, 2021


DVT and venous insufficiency, https://www.vascularsociety.org.uk/patients/conditions/13/dvt_and_venous_insufficiency

Accessed April 19, 2021


Pulmonary Embolism, https://www.mayoclinic.org/diseases-conditions/pulmonary-embolism/symptoms-causes/syc-20354647

Accessed May 5, 2021


Post-Thrombotic Syndrome, https://www.cedars-sinai.org/health-library/diseases-and-conditions/p/post-thrombotic-syndrome.html

Accessed May 5, 2021

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Written by Shienna Santelices Updated Jun 03
Medically reviewed by Jobelle Ann Dela Cruz Bigalbal, M.D.