Deep Vein Thrombosis (DVT) occurs when a blood clot forms in one of the deep veins of your body, usually in your legs, leading to either partially or completely blocked circulation. DVT usually forms in regions where blood flow is slow or disturbed.
Symptoms of DVT
Swelling, usually in one leg
Leg pain or tenderness
Reddish or bluish skin discoloration
Leg warm to touch
These symptoms of a blood clot may feel similar to a pulled muscle or a “Charlie horse.” In addition, the leg may be swollen, slightly discolored, and warm. Contact your doctor if you have these symptoms because you may need treatment right away.
If not diagnosed and treated in a timely and effective manner, pulmonary embolism (PE) can occur. A fragment of a blood clot breaks loose from the wall of the vein and migrates to the lungs, where it blocks a pulmonary artery or one of its branches. When that clot is large enough to completely block one or more vessels that supply the lungs with blood, it can result in sudden death. DVT and PE are collectively known as venous thromboembolism (VTE).
If DVT is not diagnosed and treated in a timely and effective manner, pulmonary embolism (PE) can develop.
PE occurs when a fragment of a blood clot breaks loose from the wall of the vein and migrates to the lungs, where it blocks a pulmonary artery or one of its branches. When that clot is large enough to completely block one or more vessels that supply the lungs with blood, it can result in sudden death.
Signs and Symptoms of PE
Sudden shortness of breath
Chest pain-sharp, stabbing; may get worse with deep breath
Rapid heart rate
Unexplained cough, sometimes with bloody mucus
If pulmonary embolism can be diagnosed and appropriate therapy started, the mortality rate can be reduced from approximately 30% to 10%.
More DVT Facts
Signs and Symptoms of Deep-Vein Thrombosis
DVT can strike almost anyone at risk. Genetics plays a part, but so does environment. Only about half of the people with DVT experience symptoms. (2)
Symptoms of DVT may include: (2)
-Discoloration or redness of the affected area
-Skin that is warm to the touch
Because a number of other conditions – including muscle strains, skin infections, and phlebitis (inflammation of superficial veins) – display symptoms similar to those of DVT, the condition may be difficult to diagnose without specific tests.
If your healthcare provider suspects you could have DVT, here are some of the tests that may be needed to diagnose the condition:
Doppler (Duplex Venous) Ultrasound (3)
This noninvasive procedure uses sound waves to create pictures of the blood flowing through the legs. The waves travel through the leg tissue and reflect back, enabling a computer to transform them into a moving image that can reveal the presence of a clot.
Doppler ultrasound is the most popular method for diagnosing DVT. Not only is it painless and easy to perform, it is also very effective for diagnosing blood clots (or thrombi) where they are most dangerous–in the deep veins of the upper leg and groin. It is not quite as effective when diagnosing below the knee.
In this procedure, dye is injected into a large vein in the foot or ankle. An X-ray image is then taken to reveal the location of possible clots.
Venography is one of the most accurate ways to identify DVT, but it may be uncomfortable. Occasionally it may cause phlebitis, an inflammation of the superficial veins. In addition to being invasive, venography is expensive. It also requires a high degree of expertise to perform and interpret correctly.
Magnetic Resonance Imaging (MRI) (4)
MRI uses a strong magnet to visualize the body’s internal structures and generate clear, high-quality images. Preliminary studies suggest that Magnetic Resonance Imaging may be very effective in diagnosing DVT, especially in the thigh and pelvic areas.
Risk Factors of Deep-Vein Thrombosis
Who is at risk?*
DVT can occur in almost anyone. Only about half of all patients with DVT have symptoms.5 However, certain individuals may be at increased risk for developing a DVT. Risk factors include but are not limited to: (6)
-Congestive Heart Failure
-Age > 40
-Prior or family history of venous thromboembolism (VTE)
*This is a partial list of risk factors.
What Causes Blood Clots
What Causes Blood Clots?
Blood clots can form inside a deep vein, most often in the lower leg, when the blood flow is reduced or sluggish due to: (3)
Trauma to the veins, which can be caused by
-An immune response
Prolonged immobility, which may occur following:
-Prolonged travel or sitting
A tendency for the blood to clot faster than normal (also called, hypercoagulability), which may be caused by certain blood conditions like factor V Leiden.
The risk of developing DVT is nearly eight times higher during hospitalization, (7) but many patients develop a DVT within the first month following their discharge. (8) To ensure that all patients are aware of their risk and receive the appropriate treatment throughout recovery, the Coalition is raising awareness about DVT and encouraging movement and stretching as one way to increase blood circulation and help reduce DVT risk.
DVT Complications: Pulmonary Embolism and Post-Thrombotic Syndrome (PTS)
Pulmonary embolism is a major complication of deep–vein thrombosis (DVT). A DVT blood clot has the potential to move into the lungs and block circulation to the lungs – a life-threatening condition called pulmonary embolism (PE) – which requires immediate medical attention.
PE occurs when a blood clot breaks loose from the wall of a vein and travels to the lungs, blocking the pulmonary artery or one of its branches. This blocks the blood flow from the heart. Obstruction of a large pulmonary artery by one or more of these migrating clots (emboli) may be life threatening.
Symptoms of a pulmonary embolism may include: (2)
-Unexplained shortness of breath
-Chest pain or breathing
-Rapid heart rate
-Coughing up blood
Approximately 300,000 Americans die each year from PE,5 the majority of which result from DVT. 9 Complications from DVT kill more Americans than breast cancer and AIDS combined. (10)
Anyone experiencing these symptoms should call for assistance and go to a hospital immediately.
Post-Thrombotic Syndrome (PTS)
Post-thrombotic syndrome (PTS) can occur after experiencing a DVT. The affected limb can become chronically swollen and painful. (11)
The PTS is a long-term complication of DVT that is identified by: (10)
-Chronic, persistent pain
-Development of varicose veins
PTS is common in people who have experienced a DVT and is difficult to diagnose because symptoms are similar to DVT. An estimated 330,000 people in the US have this condition. (10)
Little is known about who will or will not develop PTS. Generally, of the 60 percent who has experienced a DVT in the legs, 40 percent will experience PTS. This condition usually occurs in the first 6 months following a DVT but can also appear up to 2 years. (10)
1. Gerotziafas GT, Samama MM. Prophylaxis of venous thromboembolism medical patients. CurrOpin PulmMed. 2004; 10:356-365.2. American Public Health Association. Presented at: Public Health Leadership Conference on Deep-Vein Thrombosis: February 26, 2003: Washington, D.C. White Paper.3. National, Heart, Lung and Blood Institute. How Is Deep Vein Thrombosis Diagnosed? Available at http://www.nhlbi.nih.gov/health/dci/Diseases/Dvt/DVT_Diagnosis.html (accessed September 15, 2009).4. American Academy of Orthopaedic Surgeons (June 2001). Deep Vein Thrombosis. Retrieved August 24, 2007, from the American Academy of Orthopaedic Surgeons Web site: http://orthoinfo.aaos.org/fact/thr_report.cfm?Thread_ID=264.5. Heit et al. Am Soc Hematol. Presented a: 47th Annual Meeting and Exposition, American Society of Hematology; December 2005; Atlanta GA, Poster .6. Geerts WH, Pineo GF, Heit JA et al. Prevention of venous thromboembolism: The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest.2004; 126(suppl): 338S-400S.7. Goldhaber SZ. Deep vein thrombosis: advancing awareness to protect patient lives. White paper. American Public Health Association; Public Health Leadership Conference: Washington, DC: February 26, 2003.8. Spencer FA, Lessard D, Emery C et.al. Venous Thromboembolism in the Outpatient Setting. Arch Intern Med/Vol (NO. 14), July 23, 2007.9. Murin et al. Thromb Haemost. Comparison of the Outcomes after Hospitalization for Deep Venous Thrombosis or Pulmonary Embolism. 2002; 88:407-14.10. Gerotziafas GT, Samama MM. Prophylaxis of venous thromboembolism medical patients. CurrOpin PulmMed. 2004; 10:356-365.11. The National Alliance for Thrombosis and Thrombophila. Postthrombotic Syndrome (Venous Stress Disorder): An Indepth Guide for patients and health care providers. Available at http://www.stoptheclot.org/natt_publications/post_thrombotic_syndrome.pdf (Accessed September 16, 2009).22. Hirsh J., Hoak J. “Management of deep-vein thrombosis and pulmonary embolism A statement for healthcare professionals from the Council on Thrombosis” American Heart Association. 1996; 93:2212-2245