deep vein thrombosis
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Deep vein thrombosis
Deep vein thrombosis (DVT) is a blood clot in a major vein that usually develops in the legs and/or pelvis.
Deep vein thrombosis is a common but difficult to detect illness that can be fatal if not treated effectively. The disorder is estimated to affect 80 people per 100,000 population annually, but some experts feel this is an underestimate of the disorder because the condition often remains undetected and resolves on its on without complications. About 600,000 people are hospitalized in the United States for DVT each year. If left untreated, DVT can cause pulmonary emboli. This is a potentially fatal complication in which blood clots break off, travel through the circulatory system, and become lodged in and block an artery going to the lungs. Each year about 200,000 people die of pulmonary emboli caused by DVT. Deep vein thrombosis is also called venous thromboembolism, thrombophlebitis or phlebothrombosis.
Deep vein thrombosis is a major complication in patients who have had orthopedic surgery or pelvic, abdominal, or thoracic surgery. Patients with cancer and other chronic illnesses (including congestive heart failure), as well as those who have experienced a recent heart attack (myocardial infarction), are also at high risk for developing DVT. Deep vein thrombosis can be chronic, with recurrent episodes.
Causes and symptoms
Deep vein thrombosis is caused by blood clots in blood vessels that form in veins where blood flow is sluggish or has been disturbed, in pockets in the deep veins of the calf, or in veins that have been traumatized. Symptoms include swelling and tenderness, pain in the calf or thigh, and possibly warmth. Fewer than half of all people with the condition experience symptoms, and symptoms tend to be nonspecific (e.g., leg pain may be caused by many other conditions). Some individuals and families have underlying clotting tendencies that can be tested for.
Deep vein thrombosis can be detected through venography and radionuclide venography, Doppler ultrasonography, and impedance plethysmography. Venography is the most accurate test, but it is not used much because it is often painful, expensive, exposes the patient to radiation, and can cause allergic reactions and complications. Venography identifies the location, extent, and degree of attachment of the blood clots and enables the condition of the deep leg veins to be assessed. A contrast solution is injected into a foot vein through a catheter. The physician observes the movement of the solution through the vein with a fluoroscope while a series of x rays are taken. Venography takes 30-45 minutes and can be done in a physician's office, a laboratory, or a hospital. Radionuclide venography, in which a radioactive isotope is injected, is occasionally used, especially if a patient has had an allergic reaction to contrast solutions.
Doppler ultrasonography usually is the preferred procedure for detecting deep vein thrombosis. This technique uses sound waves to measure blood flow through leg veins and arteries. A blood pressure cuff is wrapped around the patient's ankle and a transducer with gel on it is placed over pulse points of the foot and lower leg. High-frequency sound waves bounce off the soft tissue, and the echoes are converted into images on a monitor. This procedure is very accurate in detecting clots above the knee that can become pulmonary embolisms. Usually performed in a physician's office or hospital outpatient diagnostic center, Doppler ultrasound takes about 30-45 minutes.
Impedance plethysmography is a noninvasive way to record changes in blood volume and vessel resistance. A blood pressure cuff is wrapped around the leg above the knee, four electrodes are placed near the knee and the ankle, and the cuff is inflated to compress the veins and reduce blood flow. The efficiency with which the veins return to normal is then measured. Performed in a physician's office, impedance plethysmography takes about 15 minutes.
Deep vein thrombosis can be treated with drug therapy, bed rest, and gradient elastic stockings. Medications include anticoagulants that "thin" blood to prevent further growth of blood clots, as well as clot-dissolving drugs. Heparin is a common injectable anticoagulant and is usually followed by warfarin (Coumadin) tablets for at least three months. Bed rest with the patient's legs elevated is necessary until the condition improves. Gradient elastic stockings should then be worn, and standing for long periods avoided. In some cases, a filter is surgically placed in the major vein (the inferior vena cava) to trap emboli or clots before they get to the heart and lungs. In another surgical procedure, a catheter is inserted into the vein. When the clot is reached, a balloon at the end of the catheter is inflated, and then withdrawn along with the clot. However, this procedure risks dislodging the clot.
Deep vein thrombosis can be life threatening and must be treated with conventional medical therapies. However, some alternative therapies may be used in conjunction with conventional treatments to dissolve the clot. These therapies may help support the body and prevent recurrence. A conventional physician as well as a trained alternative health care practitioner should be consulted due to the severity of this condition.
Complications from DVT can be life threatening or chronically debilitating. Pulmonary emboli develop in about 10% of people with DVT and account for about 10% of all hospital deaths. DVT also can cause inflammation of the blood vessels resulting in loss of contractility and chronically decreased function. On the other hand, about three-quarters of people with DVT remain free of symptoms, and in many cases, the condition resolves with minimal treatment.
Deep vein thrombosis can be prevented through prophylactic anticoagulant drugs and venous stasis prevention with gradient elastic stockings and intermittent pneumatic compression of the legs. Individuals should avoid standing or sitting for long periods without moving; walking or exercising the legs on long airplane and car trips helps keep blood from pooling in the legs and helps to prevent DVT. High-risk individuals often need to remain on oral anticoagulants (e.g., Coumadin) indefinitely.
- A long, thin, flexible tube that can be inserted into a vein and moved through the cardiovascular system.
- Pulmonary embolism
- An obstruction of a blood vessel in the lungs, usually caused by a blood clot that blocks a coronary artery. Pulmonary embolism can be very serious and, in some cases, fatal.
- The development of a blood clot inside a blood vessel.
For Your Information
- "Deep Vein Thrombosis, Thrombophlebitis, and Phlebitis." VascularWeb. 2009 [cited February 18, 2009]. http://www.vascularweb.org/patients/Links_To_Patient_Information/Links_to_Conditions/Deep_Vein_Thrombosis.html.
- Wedro, Benjamin C. "Deep Vein Thrombosis." MedicineNet.com. April 30, 2008 [cited February 18, 2009]. http://www.medicinenet.com/deep_vein_thrombosis/article.htm.
- "Deep Vein Thrombosis." MedlinePlus. February 17, 2009 [cited February 18, 2009]. http://www.nlm.nih.gov/medlineplus/deepveinthrombosis.html.
- American Heart Association. 7272 Greenville Avenue, Dallas, TX 75231. (800) 242-8721. http://www.americanheart.org .
- National Heart Lung and Blood Institute Health Information Center. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 592 8573. http://www.nhlbi.nih.gov.
- Society for Vascular Surgery. 633 N. St. Clair, 24th Floor, Chicago, IL 60611; Telephone: 312-334-2300or 800-258-7188. Fax: 312-334-2320; Email: firstname.lastname@example.org. http://www.vascularweb.org.
Deep vein thrombosis
deep vein thrombosis (DVT),
deep vein thrombosis
deep vein thrombosisInternal medicine A condition characterized by blood clots in veins, most often of the lower extremity, often giving rise to embolism and tissue necrosis; DVT occurs in1⁄2 of total hips without prophylactic anticoagulation, 2-3% of which evolve to fatal PE; acute DVT occurs in 1:1000 of the general population; 92% are idiopathic, ±8% are due to isolated deficiencies of protein C, protein S, antithrombin III, plasminogen Risk factors ↑ Age, immobilization, prior DVT, anesthesia, surgery, pregnancy, CA, hypercoagulability–↓ AT III, ↓ protein C, ↓ protein S, activated protein C resistance, antiphospholipid syndrome, polycythemia vera, erythrocytosis, tissue trauma–which activates coagulation, and ↑ coagulation factor XI Clinical Vague–SOB ±leg swelling, pain, edema, discoloration Diagnosis Phlebography, impedence plethysmography, compression ultrasonography–real time B mode, Doppler flow velocity, MR venography, radionuclide venography, thermography, d-dimer assay Management Anticoagulation–eg, heparin or warfarin or thrombolytic therapy–eg, alteplase or streptokinase; inferior vena caval filters; thrombectomy. See Total hip replacement.
Patient discussion about deep vein thrombosis
Q. Does anyone have any experience or suggestions regarding aerobic exercise post DVT and/or PE?
Q. Are long flights dangerous? I'm flying next week to my vacation, and the flight is going to be rather long (almost 16 hours non-stop). Several years ago, my 75 years-old aunt had blood clot in her lung after a flight of similar length. I also heard that during flight the blood in the legs clots and that it can cause after that problems with the lungs and breathing. Does this mean it's dangerous for me to fly? Should I change my ticket to shorter connection flights?
Q. How can I prevent blood clots? I am 45 years old and am supposed to go on a business trip overseas. The flight itself is 12 hours long and then I have to continue traveling by bus. Could this cause me to have blood clots? If so, how can I prevent it?