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Deep Venous Thrombosis Deep venous thrombosis often shortened DVT occurs when blood clots in a deep vein of the leg. It affects nearly 2 million people in USA every year and many die from resulting pulmonary embolism when the clot breaks off from the leg and moves to the lung. Normally blood flows freely through veins. When the flow is interrupted either by injury or by compression of the vein, the blood beyond the point of compression can clot. People at Risk of DVT: Soon after major surgery involving the hip, knee or leg After fractures of large bones in the leg Patients confined to bed after any major surgery Anyone who is bedridden for prolonged periods Women on contraceptive Pills Pregnancy and childbirth Varicose veins Airline passengers confined to their seats on long haul flights Generally the older you are the greater the chances of developing DVT. It is said that the chances double with each decade of life after 40. Symptoms: Swollen leg compared to opposite leg Leg may be warm and red Pain in the calf muscle particularly when pressure is applied Chest pain or difficulty to breathe if the clot moves to the lung Tests for DVT: Clinical examination may suggest a possible DVT. This should be confirmed by one or two tests. Ultrasound: US will usually confirm a blocked vein from a clot. D-dimer blood test: If the level of D-Dimer is raised, it is probable that you have DVT. Venography is sometimes done if the ultra sound is not very clear. Sometimes MRI or CT scan may be requested. If pulmonary embolism is suspected a Ventilation/Perfusion scan is done. Preventing DVT: Steps should always be taken to prevent a DVT rather than worry about it when it happens. In a hospital setting most of the patients who are subjected to major lower limb surgery will be prescribed blood thinning medication and maintained on it until they start walking normally. In many countries all patients admitted to hospital are also given anti embolism stockings to wear. These are elastic stockings that provide uniform compression for the leg preventing pooling of blood in the veins when they are in bed. In good operating theatres a pump will be used on anaesthetised patients, to squeeze the calf muscles intermittently to keep the blood circulating in the leg when the patient remains still. Older age group people should be encouraged to exercise regularly and advised to avoid sitting or lying in bed for prolonged periods. Long distance travelers, be it on a plane, train or bus must be encouraged to exercise the leg muscles every hour. They should be advised if possible to get out of their seat and walk in the aisle from time to time. If they are unable to do that, the least they can do is move the foot up and down at regular intervals during the flight. All these measures are particularly important for individuals who have had a DVT in the past or have a higher risk of developing DVT. Treating DVT The main goal of treating a DVT is to stop a clot from increasing in size and stop it getting to the lung. Medication used in DVT are collectively called anticoagulants. They act by turning off or delaying the clotting mechanism in the body. Heparin and Warfarin are the two main drugs used in DVT. Heparin is given by the needle and warfarin as a pill. Once DVT is suspected and diagnosed, treatment is started promptly with heparin. Action of Heparin is immediate. Warfarin which is also started with heparin takes a longer time to act (3to 5 days). Once warfarin becomes effective heparin can be discontinued. The time to discontinue heparin is determined by blood tests. While the patient is on warfarin regular blood tests will be necessary to make sure that the correct amount of warfarin is being given. Too much warfarin can cause internal bleeding. The length of time that a patient will need warfarin will depend on the cause of DVT. It can be anything between 6 weeks to a year. Anyone who suddenly develops leg pain and swelling or breathing problems within a week after being in a hospital or been on a long haul flight should seek medical advice immediately. K. Badrinath This topic was discussed in greater detail on 4th May in the “Forum” - under “General Topics