Deep Vein Thrombosis
(Blood Clot in the Leg, DVT)
Deep Vein Thrombosis (DVT) Quick Overview
- The definition of deep venous thrombosis (DVT) is a condition in which a blood clot is embedded in one of the major deep veins of the lower legs, thighs, pelvis, or arm. A clot blocks blood circulation through these veins, which carry blood from the lower body back to the heart. The blockage can cause acute pain, swelling, or warmth in the affected leg.
- Blood clots in the veins can cause inflammation (irritation) called thrombophlebitis.
- Severe complications of deep vein thrombosis occur when a clot breaks loose (or embolizes) and travels through the bloodstream, causing blockage of blood vessels (pulmonary arteries) in the lung. Called pulmonary embolism (PE), this can lead to severe difficulty in breathing and even death, depending on the degree of blockage.
- The US Centers for Disease Control and Prevention (CDC) estimates as many as 900,000 people could be affected by DVT/PE each year in the United States, and 60,000 to 100,000 Americans die of DVT/PE (also called venous thromboembolism).
Deep Vein Thrombosis (DVT) Causes
Three factors may lead to formation of a clot inside a blood vessel:
- Damage to the inside of a blood vessel due to trauma or other conditions
- Changes in normal blood flow, including unusual turbulence, or partial or complete blockage of blood flow
- Hypercoagulability, a rare state in which the blood is more likely than usual to clot
Any event or condition that can lead to blood vessel damage, hypercoagulability, or change in blood flow can potentially cause deep vein thrombosis. The more common risk factors are:
- Prolonged sitting, such as during a long plane flight or car ride
- Prolonged bed rest or immobility, such as after injury or during illness (for example stroke)
- Recent surgery, particularly orthopedic, gynecologic, or heart surgery
- Recent trauma to the lower body, such as fractures of the bones of the hip, thigh, or
- Heart attack or heart failure
- Pregnancy or recent childbirth
- Being at very high altitude, greater than 14,000 feet
- Use of estrogen therapy or birth control pills
- Rare inherited genetic conditions that lead to changes in certain blood clotting factors
- Certain heart or respiratory conditions
- Advanced age
- Medical conditions that affect the veins such as vasculitis (inflammation of the vein walls), varicose veins
Superficial venous thrombosis (SVT) occurs when a blood clot forms in a superficial vein near the surface of the body. While not the same as DVT (which occurs in deep veins) it can be a risk factor for DVT/PE
- Disseminated intravascular coagulation (DIC), a medical condition in which blood clotting occurs inappropriately, usually caused by overwhelming infection or organ failure
If an individual has one deep vein thrombosis, they are 33% more likely to develop a second deep vein thrombosis within 10 years.
Medically Reviewed by a Doctor on 9/28/2015
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