| Deep vein thrombosis (DVT) is the formation of a blood clot (thrombus) in a vein, usually deep within the muscle of the lower leg (calf) or thigh area. The blood clot is composed of different factors found in the blood, and forms in a blood vessel which causes obstruction of blood flow through the vessel, usually at a site that has been narrowed by atherosclerosis (hardening of the arteries). If a thrombus detaches from the vein, the formation is then called an embolism. Emboli pass through the bloodstream to the heart, brain, or other vital organs, and cause obstruction of blood flow to those organs; this may result in stroke or organ damage. If the embolism lodges in a lung artery, it is called a pulmonary embolism, and it can be fatal.
When a blood clot forms in a superficial vein, as opposed to a deep vein, it is referred to as thrombophlebitis, phlebitis, or superficial venous thrombosis. These clots do not travel to other organs and are not considered as serious.Risk: Risk factors for DVT include prolonged bed rest or immobilization for long periods of time, recent surgery and/or orthopedic procedures, limb trauma, stroke, myocardial infarction, congestive heart failure, ulcerative colitis, Crohn's disease, previous or current cancer, obesity, a family history of deep vein thrombosis, varicose veins, coagulation abnormalities, childbirth within the past 6 months, and the use of estrogen or birth control pills. The male to female ratio is 1.2 to 1 (Schreiber). Individuals over the age of 40 are more likely to develop the condition.
Individuals who have had previous DVT are 5 times more likely to develop another DVT, and from 26% to 68% more likely to have DVT postoperatively (Feied). In addition, individuals who receive a general anesthetic for surgery have 5 times the risk of DVT as those receiving an epidural anesthetic (Feied). Incidence and Prevalence: There are an estimated 600,000 new cases of DVT each year in the US (Society of Interventional Radiology). However, up to two-thirds of cases of DVT are unrecognized (Ennis). It is estimated that the true incidence of DVT is 80 cases per 100,000 annually (Schreiber).
If preoperative anticoagulant therapy is not utilized, incidence of DVT following total knee replacement is 60% to 85%, and after total hip replacement incidence is 50% to 60% (Ennis). Eight percent of all cases of DVT occur in the upper extremity, possibly in part due to the placement of central venous catheters for renal dialysis, and cardiac pacemakers (Greben). |
Source: Medical Disability Advisor
| History: A history of prolonged sitting, immobilization, or bed rest may be reported. Symptoms often include pain, tenderness, warmth, or swelling in only one leg. Reddening and/or fatigue of the leg may be reported. Certain individuals may have a low grade fever. Many individuals report no symptoms. Physical exam: The extremity may feel cold and look pale or blue/grey (cyanotic). Surface veins may be prominent. If the lower leg (calf) is affected, there may be a positive Homan's sign, in which the calf muscles become increasingly painful upon ankle dorsiflexion with the knee fully extended. Tests: Doppler ultrasonography is a noninvasive test that is most commonly used to identify obstructed vessels. Plethysmography is another test which can be used to evaluate the presence of venous obstruction. Less often, a venogram, or x-ray of the veins, may be performed. Dye is injected into a vein, which makes it visible, and an x-ray is taken. As with Doppler ultrasound, this test can identify the location of severe venous obstruction in the limb. Rarely, MRI or CT scan may be performed. |
Source: Medical Disability Advisor
| Individuals with a peripheral thrombosis above the knee are often admitted to the hospital for observation. Treatment includes administration of intravenous or subcutaneous blood thinners (anticoagulation therapy) and, in some cases, thrombolytic agents (fibrinolytic therapy). Vena cava filters may be used if an individual cannot take blood-thinning medications. An embolectomy, a procedure to remove the clot with a catheter, or surgery may be recommended.
If the thrombus is below the knee, the likelihood of an embolism is quite small, and the individual may be treated with anti-inflammatory medications and local compresses. Serial ultrasound tests may be performed over a period of 7 to 10 days to assess for any growth or extension of the thrombus above the knee. If this occurs, anticoagulation therapy is generally given.
Treatment may also include the use of graduated compression stockings, which cause pressure on the leg, diverting blood flow from the superficial vessels, increasing blood flow through the deep veins and lessening the likelihood of subsequent clot formation. |
Source: Medical Disability Advisor
| Although the prospect for recovery from a peripheral venous thrombosis is good, there is a modest long-term risk of chronic venous insufficiency, called postphlebitic syndrome. In this setting, individuals may have chronic swelling and tenderness of the affected leg, and have an increased risk of recurrent thrombosis. It is difficult to predict which patients will develop this syndrome. An estimated 20% of untreated above-the-calf DVTs progress to pulmonary emboli, which, in 10% to 20% of cases, is fatal (Schrieber). With proper treatment, the mortality rate decreases significantly. When DVT is treated promptly, pulmonary emboli do not usually occur.
The recurrence rate of DVT in individuals treated with anticoagulation therapy is 18.7%, but only 7.7% in those treated with fibrinolytic therapy (Feied). |
Source: Medical Disability Advisor
| The goal of rehabilitation is to improve circulation in the legs. A supervised exercise program with an emphasis on walking may be helpful. |
Source: Medical Disability Advisor
| Complications include pulmonary embolism, systemic embolism, chronic venous insufficiency, and hemorrhage due to anticoagulant therapy. Postphlebitic syndrome (chronic pain and swelling, leg ulcer formation, and recurrence of the DVT) may occur in 2% to 5% of individuals (Podnos). |
Source: Medical Disability Advisor
| Occupations requiring walking, standing, and heavy labor are more likely to be affected than sedentary occupations. Work accommodations may be required to allow individuals with peripheral thrombosis to improve the circulation in their legs, which may involve taking frequent breaks or short walks. For individuals receiving anticoagulants, work resulting in significant risk of trauma should be avoided. |
Source: Medical Disability Advisor
| If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case. Regarding diagnosis:
- Has individual provided the physician with an adequate medical history, including information about past injuries to the leg; smoking history; use of birth control pills or other medications increasing thrombotic risk; or chronic conditions such as cancer, high blood pressure, hyperlipidemia or other risk factors for peripheral thrombosis?
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Has the diagnosis been confirmed by Doppler ultrasound, plethysmography, venography, or other tests to identify the existence and location of an obstructed blood vessel?
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Has individual recently been immobile for a long period of time due to illness or travel?
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Has individual recently had limb trauma or an orthopedic procedure?
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Is individual obese?
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Does individual have clotting abnormalities?
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Has individual given birth within the past six months?
Regarding treatment:
- Has individual been treated with anticoagulants or thrombolysis?
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Have other specialists been consulted to treat coexisting chronic diseases that might complicate or prolong recovery?
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Has a vascular surgeon been consulted to evaluate the options for surgical treatment?
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Is good skin care being provided to the affected limb in order to prevent infection?
Regarding prognosis:
- Does individual have risk factors associated with poor outcome, such as advanced age or presence of anticardiolipin antibodies?
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Is there evidence of recurrence?
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Source: Medical Disability Advisor
| Ennis, Robert. "Deep Venous Thrombosis Prophylaxis in Orthopedic Surgery." eMedicine. Eds. Miguel A. Schmitz, et al. 15 Dec. 2004. Medscape. 1 Feb. 2005 <http://emedicine.com/orthoped/topic600.htm>.Feied, Craig. "Deep Venous Thrombosis." eMedicine. Eds. William Pearce, et al. 17 Nov. 2004. Medscape. 1 Feb. 2005 <http://emedicine.com/med/topic2785.htm>. Greben, Craig, et al. "Deep Venous Thrombosis, Upper Extremity." eMedicine. Eds. Anthony Watkinson, et al. 9 May. 2003. Medscape. 1 Feb. 2005 <http://emedicine.com/radio/topic774.htm>. Podnos, Yale D., Russell A. Williams, and Deron J. Tessier. "Chronic Venous Insufficiency." eMedicine. Eds. William Pearce, et al. 25 Nov. 2004. Medscape. 1 Feb. 2005 <http://emedicine.com/med/topic2760.htm>. Schreiber, Donald. "Deep Venous Thrombosis and Thrombophlebitis." eMedicine. Eds. Francis Counselman, et al. 13 Oct. 2004. Medscape. 26 Jan. 2005 <http://emedicine.com/emerg/topic122.htm>. Society of Interventional Radiology. "Deep Vein Thrombosis Overview." Society of Interventional Radiology. 31 Aug. 2004 <http://www.sirweb.org/patPub/DVTOverview.shtml>. |
Source: Medical Disability Advisor
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