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Deep Vein Thrombosis

Last updated May 21, 2018

Approved by: Krish Tangella MD, MBA, FCAP

Deep vein thrombosis (DVT) happens when a blood clot forms in a deep vein and is most common in the deep veins of your lower leg.


What are the other Names for this Condition? (Also known as/Synonyms)

  • Blood Clot in the Legs
  • Deep Venous Thrombosis
  • Thrombophlebitis

What is Deep Vein Thrombosis? (Definition/Background Information)

  • Veins are blood vessels that carry blood to the heart, from other body regions. There are two types of veins, namely superficial veins that lie just below the skin, and deep veins, located deep within the body (such as the leg muscles).
  • Deep Vein Thrombosis (DVT) is a blood clot that occurs in a deep vein of the leg. Most of these blood clots occur in the leg or thigh; though, they may also occur in other parts of the body. A calf vein in the leg, is the most common site for a DVT (clot) to occur.
  • When an individual suffers from such a condition, the blood flow in the vein is partially or completely stopped by the blood clot.

Who gets Deep Vein Thrombosis? (Age and Sex Distribution)

  • Deep Vein Thrombosis can occur in any individual, at any age
  • Adults, over the age of 60 years are commonly affected by this condition, with a slightly higher male incidence

What are the Risk Factors for Deep Vein Thrombosis? (Predisposing Factors)

Risk factors that increase the incidence of Deep Vein Thrombosis are:

  • Immobility: Sitting in a single place for a long time without moving the legs, can affect the flow of blood in the veins and consequently lead to DVT, like during a long distance air/train/car travel
  • Surgical operation: During surgery, the individual is administered anesthesia and hence remains immobilized/still, for long hours. This could cause a paralysis in some muscles and slow down the blood flow in the veins, increasing the risk of blood clots
  • Illness or injury that causes immobility for a long time duration, like a leg fracture (especially in the long bones of the leg)
  • Damages caused to the inside lining of the vein due to:
    • Inflammation of the vein wall
    • Drugs taken for curing certain illnesses; chemotherapy drugs may damage the veins
    • Injury to the vein caused by needle, when an intravenous catheter is inserted into a vein
    • Consumption of harmful drugs like heroin
  • Other reasons for blood clot formation may include:
    • Nephrotic syndrome (kidney disease)
    • Thrombophilia (a blood coagulation abnormality)
    • Rare inherited conditions (like Factor V Leiden mutation)
    • Family history of blood clotting disorders
  • Use of contraceptive pills; these contain estrogen which can clot blood more easily
  • Hormone replacement therapy: Those undergoing this therapy have a high risk of contracting Deep Vein Thrombosis
  • Individuals with cancer or heart diseases, are more susceptible than others
  • Male adults over the age of 60 years have a higher risk
  • Pregnancy
  • Obesity or overweight conditions
  • Dehydration
  • Smoking
  • A pacemaker catheter that passes through the vein in the groin
  • Polycythemia vera: A disorder, where the bone marrow makes too many blood cells, causing the blood to become thicker and slower

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Deep Vein Thrombosis? (Etiology)

A  Deep Vein Thrombosis may be caused due to the following reasons:

  • When the inner lining of the veins are damaged, which may be due to physical, chemical, and biological factors, such as:
    • Surgery
    • Serious injuries
    • Inflammation
    • Immune responses
  • Sluggishness or slowness in the flow of blood, which may be due to:
    • Lack of motion that occurs from a recent surgery, or if an individual is confined to bed rest after a long illness, or has been traveling for a long time at a stretch
    • When the blood becomes more thicker, which may be due to inherited conditions (such as Factor V Leiden), or hormone therapy, the use of contraceptive pills, or caused by blood-related disorders (like polycythemia vera)

What are the Signs and Symptoms of Deep Vein Thrombosis?

The signs and symptoms of Deep Vein Thrombosis include:

  • Pain and tenderness of the calf muscle
  • Calf muscles begins to swell
  • Changes in skin color
  • Skin feels warmer to touch

How is Deep Vein Thrombosis Diagnosed?

Deep Vein Thrombosis can be diagnosed by adopting the following procedures:

  • Physical examination, to check for symptoms like red, swollen, and tender calf muscle, including evaluation of medical history
  • Laboratory tests performed might include:
    • D-Dimer blood test
    • Doppler ultrasound exam of the legs

Blood tests are done to check for the following:

  • Activated protein C resistance (for any genetic defect)
  • Antithrombin III levels
  • Antiphospholipid antibodies
  • Complete blood count
  • Genetic testing to check for mutations
  • Lupus anticoagulant
  • Protein C and protein S levels

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Deep Vein Thrombosis?

The major complications that might arise from Deep Vein Thrombosis are pulmonary embolism and post-thrombotic syndrome, which are explained below:

Pulmonary embolism: A blood clot may break away and move up through the bloodstream and block the lungs, leading to a condition known as pulmonary embolism. Any individual with a pulmonary embolism might be at risk for the following complications:

  • Sudden cough accompanied by bloody sputum
  • Rapid breathing or shortness of breath; breathing difficulties
  • Chest pain, which may be sharp, severe, and intense
  • Palpitations of the heart
  • Heart failure
  • Cardiogenic shock
  • Pulmonary hypertension

Post-thrombotic syndrome: When a clot remains in the vein for a very long time, it can damage the veins or the valve in the veins. If the valve is damaged, it causes the blood to backflow, called reflux, which causes blood to pool in the leg. Due to this, further complications may be observed, like:

  • Pain
  • Swelling and fluid buildup, called edema
  • Hyperpigmentation, the skin color becomes dark
  • Ulcers of the skin
  • Swollen veins called varicose veins
  • Recurrent DVT or primary embolism

How is Deep Vein Thrombosis Treated?

Treatment and management methods for Deep Vein Thrombosis include:

  • Anticoagulant medications are prescribed to thin blood
  • Heparin is normally the first drug administered (through a vein), and this requires hospitalization
  • Warfarin drug is administered orally along with heparin, and it may be continued for more than 3 months or longer
  • The use of pressure stockings, which is worn on the legs, helps improve the blood flow in the legs and reduce the complications arising out of a blood clot
  • Surgery may be recommended if medicines are not helpful. The procedures may involve:
    • A filter may be placed in the largest vein, in order to prevent blood clots from moving to other parts of the body, from the lungs
    • Removing blood clots in the vein

How can Deep Vein Thrombosis be Prevented?

The following preventive measures may be adopted for reducing the risk of Deep Vein Thrombosis:

  • The pressure stockings, prescribed by the doctor, should be worn continuously to improve blood flow in the legs
  • Try not to remain immobile for a long duration especially while traveling or taking a long drive. Move your legs during a long plane trip or long distance drive; avoid sitting in one place for a very long time
  • Individuals having a high risk for DVT could take heparin shots (per physician’s advice), while going on long air/car trips
  • Stop smoking completely

What is the Prognosis of Deep Vein Thrombosis? (Outcomes/Resolutions)

  • In most cases Deep Vein Thrombosis cures without any complications; however, the risk of recurrence is always present
  • Some individuals may experience long-term pain and swelling in the legs, called postphlebtic syndrome. Sometimes, pain and changes in skin color, may also be seen
  • In some cases, the blood clots in the thighs, may break-off and travel to the lungs, which may lead to dangerous medical issues

Additional and Relevant Useful Information for Deep Vein Thrombosis:

Polycythemia vera is a blood-related disorder, in which there is too much red blood cells being produced by the body, causing the blood to thicken. Formation of blood clots, due to the accumulation of red blood cells, is a complication associated with this disorder.

What are some Useful Resources for Additional Information?


References and Information Sources used for the Article:


Helpful Peer-Reviewed Medical Articles:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Aug. 10, 2013
Last updated: May 21, 2018