Thrombosis
Thrombosis, formation of a blood clot, or thrombus, inside a blood vessel. Forming a clump of various blood cells, the clot remains attached at its point of formation, partially or completely blocking the flow of blood through the vessel. A clot that breaks free and travels to a different part of the circulatory system is called an embolism.
The chief causes of thrombosis are injury to the inner lining of a blood vessel; blood disorders that result in thickened blood and an increased tendency toward clotting; and restricted blood flow, caused by such problems as obesity. People with the condition known as atherosclerosis are at special risk for thrombosis because their arteries are partially blocked by an accumulation of fatty tissue largely due to elevated levels of cholesterol in the blood. Diets high in saturated fats, such as in eggs and dairy products, are likely to raise blood cholesterol levels.
When thrombosis occurs in an artery, the tissues that the artery normally supplies with blood suffer infarction—that is, they die from a lack of blood-borne nutrients. Coronary thrombosis, the blockage of an artery that supplies blood to heart muscle, results in a myocardial infarction, or heart attack. Cerebral thrombosis, thrombosis in an artery leading to the brain, results in a stroke. Blood clots may cause obstructions in arteries leading to the retina of the eye, the kidneys, the intestines, as well as to the limbs.
Veins as well as arteries may be damaged by thrombosis. When a clot forms in a vein near the surface of the skin, it leads to thrombophlebitis. This condition causes swelling and inflammation where the clot develops in the vein. People with varicose veins are at particular risk for this disorder. Deep vein thrombosis usually strikes older people with poor blood circulation that results from a weakened heart or an extended period of bed rest. Obesity may also contribute to deep vein thrombosis.
The treatment of thrombosis usually involves the administration of anticoagulants, or drugs that discourage clotting. Anticoagulants range from simple medications like aspirin to complex organic acids like heparin. Enzymes such as streptokinase that are capable of dissolving clots may be administered as an alternative. There are also surgical techniques for removing particularly threatening clots.
The chief causes of thrombosis are injury to the inner lining of a blood vessel; blood disorders that result in thickened blood and an increased tendency toward clotting; and restricted blood flow, caused by such problems as obesity. People with the condition known as atherosclerosis are at special risk for thrombosis because their arteries are partially blocked by an accumulation of fatty tissue largely due to elevated levels of cholesterol in the blood. Diets high in saturated fats, such as in eggs and dairy products, are likely to raise blood cholesterol levels.
When thrombosis occurs in an artery, the tissues that the artery normally supplies with blood suffer infarction—that is, they die from a lack of blood-borne nutrients. Coronary thrombosis, the blockage of an artery that supplies blood to heart muscle, results in a myocardial infarction, or heart attack. Cerebral thrombosis, thrombosis in an artery leading to the brain, results in a stroke. Blood clots may cause obstructions in arteries leading to the retina of the eye, the kidneys, the intestines, as well as to the limbs.
Veins as well as arteries may be damaged by thrombosis. When a clot forms in a vein near the surface of the skin, it leads to thrombophlebitis. This condition causes swelling and inflammation where the clot develops in the vein. People with varicose veins are at particular risk for this disorder. Deep vein thrombosis usually strikes older people with poor blood circulation that results from a weakened heart or an extended period of bed rest. Obesity may also contribute to deep vein thrombosis.
The treatment of thrombosis usually involves the administration of anticoagulants, or drugs that discourage clotting. Anticoagulants range from simple medications like aspirin to complex organic acids like heparin. Enzymes such as streptokinase that are capable of dissolving clots may be administered as an alternative. There are also surgical techniques for removing particularly threatening clots.
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