It has been suggested that Deep Vein Thrombosis be merged into this article or section.   (Discuss)

Deep venous thrombosis (or DVT) is the occlusion of a deep vein by a blood clot ("thrombus"). It generally affects the leg veins, such as the femoral vein or the popliteal vein, or occasionally the veins of the arm ("Paget-von Schroetter syndrome"). Thrombophlebitis is the more general class of pathologies of this kind. Image File history File links Please see the file description page for further information. ... It has been suggested that this article or section be merged with Deep venous thrombosis. ... Mark 3 DVT at Norwich station A Driving Van Trailer or DVT is a purpose built railway vehicle which allows the driver to operate a locomotive from the rear end of a train. ... In biology, a vein is a blood vessel which returns blood from the microvasculature to the heart. ... A thrombus is the final product of blood coagulation, through the aggregation of platelets and the activation of the humoral coagulation system. ... In an extended sense, a leg is any part of an object that supports it off the ground. ... In biology, a vein is a blood vessel which returns blood from the microvasculature to the heart. ... In the human body, the femoral vein is a blood vessel that accompanies the femoral artery in the same sheath. ... The politeal vein parrallels the popliteal artery but carries the blood from the knee joint and muscles in the thigh and calf back to the heart. ... ARM may stand for: Most likely: ARM Ltd (originally Advanced RISC Machines) ARM architecture CPU design or one of its derivatives developed by ARM Ltd (originally called The Acorn RISC Machine) Adjustable rate mortgage Annotated Reference Manual (C++) Artificial rupture of membranes (see amniotic sac) the ISO 3166-1 3... Thrombophlebitis is phlebitis (vein inflammation) related to a blood clot or thrombus. ...

Signs and symptoms

Classical symptoms of DVT include pain, swelling and redness of the leg, starting with the calf and progressing upwards. In many patients, the symptoms are more insidious. In up to 25% of all hospitalised patients, there may be some form of DVT, which often remains clinically inapparent (unless pulmonary embolism develops). According to the International Society for the Study of Pain, there are two different terms: pain and nociception. ... Edema (BE: oedema, formerly known as dropsy) is swelling of any organ or tissue due to accumulation of excess fluid. ... In an extended sense, a leg is any part of an object that supports it off the ground. ...

There are several techniques during physical examination to increase the a priori likelihood of DVT. These include measuring the circumference of the affected and the contralateral limb at a fixed point (to objectivate oedema), and palpating the venous tract, which is often tender. Edema (BE: oedema, formerly known as dropsy) is swelling of any organ or tissue due to accumulation of excess fluid. ... In biology, a vein is a blood vessel which returns blood from the microvasculature to the heart. ...

A careful history has to be taken considering risk factors (see below), including the use of the oral contraceptive pill, recent long-haul flying, a history of miscarriage (which is a feature of several disorders that can also cause thrombosis). A family history can reveal a hereditary factor in the development of DVT. Oral contraceptives are contraceptives which are taken orally and inhibit the bodys fertility by chemical means. ... Miscarriage is the lay term for the natural or accidental termination of a pregnancy at a stage where the embryo or the fetus is incapable of surviving. ... A genetic disorder, or genetic disease is a disease caused, at least in part, by the genes of the person with the disease. ...

It is vital that the possibility of pulmonary embolism is excluded in the history, as this may warrant further investigation (see pulmonary embolism).

Diagnosis

In a low-probability situation, current practice is to commence investigations by testing for D-dimer levels. This fibrin degradation product is an indication that thrombosis is occurring, and that the blood clot is being dissolved by plasmin. A low D dimer level should prompt other possible diagnoses (such as a ruptured Baker's cyst, if this has not been considered as part of the history). D-dimer is a blood test performed in the medical laboratory to diagnose thrombosis. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... A thrombus is the final product of blood coagulation, through the aggregation of platelets and the activation of the humoral coagulation system. ... Plasmin is an important degrading enzyme (EC 3. ... A Bakers cyst, otherwise known as a popliteal cyst, is a benign swelling found over the knee joint. ...

Other blood tests usually performed at this point are:

• full blood count
• coagulation studies: PT, APTT, thrombin time, INR
• liver enzymes
• renal function and electrolytes

In cases of higher suspicion, compression ultrasound scanning of the leg veins, combined with duplex measurements (to determine blood flow), can reveal a blood clot and the extent of it (i.e. whether it is below or above the knee). A full blood count (FBC) or complete blood count (CBC) is a test requested by a doctor or other medical professional that gives information about the cells in a patients blood. ... The coagulation of blood is a complex process during which blood forms solid clots. ... The prothrombin time (PT) and its derived measures of prothrombin ratio (PR) and international normalized ratio (INR) are measures of the extrinsic pathway of coagulation. ... The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT) is a commonly performed test for the system of coagulation, especially its intrinsic pathway. ... The prothrombin time (PT) and its derived measures of prothrombin ratio (PR) and international normalized ratio (INR) are measures of the extrinsic pathway of coagulation. ... Liver function tests (LFTs or LFs), are groups of clinical biochemistry laboratory blood assays designed to give a doctor or other health professional information about the state of a patients liver. ... In medicine (nephrology) renal function is an indication of the state of the kidney and its role in physiology. ... An electrolyte is a substance which dissociates free ions when dissolved (or molten), to produce an electrically conductive medium. ... Medical ultrasonography is an ultrasound-based diagnostic imaging technique used to visualize internal organs, their size, structure and their pathological lesions. ... A thrombus is the final product of blood coagulation, through the aggregation of platelets and the activation of the humoral coagulation system. ... An x-ray of a human knee In human anatomy, the knee is the leg joint connecting the femur and the tibia. ...

When all the above remains inconclusive, the gold standard is intravenous venography, which involves injecting a peripheral vein of the affected limb with a contrast agent and taking X-rays, to reveal whether the venous supply has been obstructed. Impedance plethysmography can also be used as a non-invasive alternative. 1922 U.S. gold certificate The gold standard is a monetary system in which the standard economic unit of account is a fixed weight of gold. ... In biology, a vein is a blood vessel which returns blood from the microvasculature to the heart. ... Radiocontrast agents (or simply contrast agents) are compounds used to improve the visibility of internal bodily structures in an X-ray image. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... In biology, a vein is a blood vessel which returns blood from the microvasculature to the heart. ... Impedance phlebography, or impedance plethysmography, is a non-invasive medical test that measures small changes in electrical resistance of the calf or other regions of the body. ...

Therapy

Anticoagulation is the usual treatment for DVT. Thrombolysis is generally reserved for serious pulmonary embolism. An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. ... Thrombolysis is the breakdown (lysis) by pharmacological means, of blood clots. ...

Generally, patients are initiated on heparin treatment while they start on a 3- to 6-month course of warfarin (or related vitamin K inhibitors). Often, low molecular weight heparin is substituted for the regular heparin. In patients who have had recurrent DVTs (two or more), anticoagulation is generally "life-long". Heparin (also known as calciparine {United States, United Kingdom, Canada}, liquaemin{United States}, calcilean/hepalean/heparin leo {Canada}) is an injectable anticoagulant, nowadays usually made synthetically. ... Warfarin (also known under the brand name Coumadin®) is an anticoagulant medication that can be administered orally. ... This article describes the biomolecule known as Vitamin K. For the unrelated drug sometimes referred to in slang as Vitamin K, see Ketamine. ... In medicine, low molecular weight heparin (LMWH) is a class of medication used as an anticoagulant in diseases that feature thrombosis, as well as for prophylaxis in situations that lead to a high risk of thrombosis. ... Heparin (also known as calciparine {United States, United Kingdom, Canada}, liquaemin{United States}, calcilean/hepalean/heparin leo {Canada}) is an injectable anticoagulant, nowadays usually made synthetically. ...

In patients who cannot have anticoagulant treatment (e.g. they have active peptic ulcer disease or are prone to cerebral hemorrhage), or those who have recurrent PEs while on anticoagulation, an inferior vena caval filter (Greenfield filter) may prevent pulmonary embolisation of the leg clot. As these filters are themselves potential foci of thrombosis, they are generally only used in the short term.

Prophylaxis

In patients who have undergone surgery, low molecular weight heparins are routinely administered to prevent thrombosis. However, early and regular ambulation (walking) is a treatment that predates anticoagulants and is still recognized and used today. Walking activates the body's muscle pumps, increasing venous velocity and preventing stasis. Intermmittent pneumatic compression (IPC) machines have proven protective in bed- or chair-ridden patients at very high risk or with contraindications to heparins. IPC machines use air bladders that are wrapped around the thigh and/or calf. The bladders arternately inflate and deflate, squeezing the muscles and increasing blood velocity by as much as 500%. IPC machines have been proven effective on knee and hip surgery patients (a population with a risk as high as 80% with no prophylactic treatment) of developing DVT and PE. A typical modern surgery operation For other meanings of the word, see Surgery (disambiguation) Surgery (from the Greek cheirourgia - lit. ... In medicine, low molecular weight heparin (LMWH) is a class of medication used as an anticoagulant in diseases that feature thrombosis, as well as for prophylaxis in situations that lead to a high risk of thrombosis. ...

Pathogenesis

Main article: Thrombosis
Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ...

Thrombosis is a multifactorial process, caused by the nature of blood flow, the consistency of the blood, and qualities of the vessel wall (Virchow's triad). Amongst the plethora of risk factors, immobilisation, female gender, use of oral contraceptives and air travel ("economy class syndrome") are some of the better-known causes. Thrombophilia (tendency to develop thrombosis) often expresses itself with recurrent thromboses. Gender, for the purposes of this article, is the perceived or projected (self-identified) masculinity or femininity of a person. ... Oral contraceptives are chemicals taken by mouth to inhibit normal fertility. ... This article refers to the tool of travel. ... Economy class syndrome was coined in the late 1990s when it turned out that people who has traveled long distances by aeroplane were at an increased risk for thrombosis, especially deep venous thrombosis and its main complication, pulmonary embolism. ... Thrombophilia is the propensity to develop thrombosis (blood clots) due to an abnormality in the system of coagulation. ...

It is recognised that thrombi usually develop first in the calf veins, "growing" in the direction of flow of the vein. DVTs are distinguished as being above or below the popliteal vein. Very extensive DVTs can extend into the iliac vein or the inferior vena cava. The risk of pulmonary embolism is higher in more extensive clots. Popliteal refers to anatomical structures locatedin the back of the knee: popliteal artery popliteal vein popliteal fossa popliteal nerves ... This article may be too technical for most readers to understand. ...

Epidemiology

DVT's occur in about 1 per 1000 persons per year. About 1-5% will die from the complications (i.e. pulmonary embolism).