Thrombosis is the formation of a thrombus or blood clot, which may partially or completely block a blood vessel.
If blood clots form in a deep vein, the result is called deep vein thrombosis.
Although the condition occurs most frequently in the legs and lower abdomen, it can occur anywhere in your body.
Deep vein thrombosis is fairly rare, but if you are elderly or overweight, you are particularly susceptible.
The disorder also may affect anyone with a blood disease such as polycythemia, and women who are pregnant or those who are taking estrogen, either in the form of birth control pills or as postmenopausal therapy.
The condition often develops after long periods of immobility, especially while you recover from an illness.
This is because at such times your blood flow has a tendency to become quite sluggish.
The area drained by the vein, usually your calf or thigh, becomes swollen and painful as the normal flow of blood is obstructed.
This raises the pressure in your veins and capillaries.
In your leg this causes edema, or cushion-like swellings that can remain indented if you press them with a finger.
If the thrombosis is not in your leg, there may be no symptoms unless pieces of the clot break off, enter the blood, and cause pulmonary embolism.
If you think you may have a deep vein thrombosis, see your physician, who will examine you, particularly your heart, lungs and circulation.
To locate a deep-vein thrombosis in your leg, the physician may require venography (X-rays taken after a dye is injected into a vein in your foot).
Among the tests that may be used in certain cases are ultrasound and radioactive fibrinogen tests.
Radioisotope scanning of the lungs is used to check if any blood clots have been carried in the bloodstream to the lungs and caused pulmonary embolism.
If you are about to have surgery for any reason and your physician believes you are susceptible to deep vein thrombosis, you may be given injections of a blood thinner (anticoagulant) drug both before and after the operation.
If you are bedridden, you will probably be encouraged to flex your leg muscles, wiggle your toes, and bend your ankles to keep your circulation active.
If you are immobilized for a long time, your legs also may be mechanically elevated and put in plastic bags, which are alternately filled with air and deflated.
The resultant pumping effect keeps your blood flowing normally.
If deep vein thrombosis has already occurred, and especially if blood clots have traveled to the lungs, you may be given treatment with fibrinolytic drugs, which dissolve the clots, and with anticoagulants, which prevent the formation of further clots.
Because these drugs can cause unwanted bleeding if you use them incorrectly, you must take them exactly as they are prescribed, usually for a period of several weeks.
An analgesic prescribed by your physician will help relieve any pain from which you may be suffering.
Most clots are gradually reabsorbed into the bloodstream.
Sometimes, surgery is necessary to remove blood clots especially if there is a possibility of pulmonary embolism.