Thrombosis

thrombosis (thrŏmbō`sĭs), obstruction of an artery or vein by a blood clot (thrombus). Arterial thrombosis is generally more serious because the supply of oxygen and nutrition to an area of the body is halted. Thrombosis of one of the arteries leading to the heart (heart attack; see infarction) or of the brain (stroke) can result in death and, in a vessel of the extremities, may be followed by gangrene. Acute arterial thrombosis often results from the deposition of atherosclerotic material in the wall of an artery, which gradually narrows the channel, precipitating clot formation (see arteriosclerosis). A thrombus that breaks off and circulates through the bloodstream is called an embolus.

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thrombosis

Formation of a blood clot (thrombus) in the heart or a blood vessel. Contributing factors include injury to a blood vessel's lining from inflammation (thrombophlebitis) or atherosclerosis, blood flow that is turbulent (e.g., from an aneurysm) or sluggish (e.g., from prolonged bed rest), or coagulation abnormalities (e.g., from high numbers of platelets or excessive fats in the blood). Thrombosis, especially in deep veins of the leg, is a particular danger after major surgery. A thrombus can block blood flow at the point of clot formation or break free to block it elsewhere (embolism).

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thrombosis

1. the formation or presence of a thrombus

2. Informal short for coronary thrombosis

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thrombosis [thräm′bō·səs]

(medicine)

Formation of a thrombus.

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Thrombosis 

the formation of blood clots during life in the lumen of a blood vessel or in the heart.

Thrombogenesis is promoted by injury to the vascular wall owing to atherosclerosis or inflammation, by the slowing of the blood flow, and by an increase in the coagulability and viscosity of the blood. Peripheral venous thrombosis is most common; thrombosis in the arterial system occurs less frequently. Arterial thrombosis interferes with the blood supply to areas of tissue and often leads to necrosis of such tissue. For example, coronary thrombosis results in myocardial infarction, and cerebral thrombosis, in a stroke, or cerebrovascular accident. The thrombus may subsequently either dissolve (undergo lysis), with partial or complete restoration of the blood vessel’s patency, or it may become thickened (organized). Multiple capillary thrombosis, a syndrome involving disseminated intravascular blood coagulation, is often combined with an increased tendency for tissues to bleed. The condition may develop during shock, hemorrhage, or severe infectious diseases, or it may be a manifestation of intolerance for drugs.

Biochemical and roentgenological methods of examination are used to diagnose thrombosis. Treatment includes the administration of anticoagulants, antispasmodics, and fibrinolytic and anti-inflammatory agents, as well as surgical removal of the thrombus.

REFERENCES

Machabeli, M. S. Koagulopaticheskie sindromy. Moscow, 1970.
Kuznik, B. I., and V. P. Skipetrov. Formennye elementy krovi, sosudistaia stenka, gemostaz i tromboz. Moscow, 1974.
Raby, C. Lokalizovannaia i rasseiannaia vnutrisosudistaia koaguliatsiia. Moscow, 1974. (Translated from French.)
Quick, A. J. Hemorrhagic Diseases and Thrombosis, 2nd ed. Philadelphia, Pa., 1966.

A. N. SMIRNOV and V. D. TOPOLIANSKII