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 infarctioninfarction,
blockage of blood circulation to a localized area or organ of the body resulting in tissue death. Infarctions commonly occur in the spleen, kidney, lungs, brain, and heart.
..... Click the link for more information. ) or of the brain (strokestroke,
destruction of brain tissue as a result of intracerebral hemorrhage or infarction caused by thrombosis (clotting) or embolus (obstruction in a blood vessel caused by clotted blood or other foreign matter circulating in the bloodstream); formerly called apoplexy.
..... Click the link for more information. ) can result in death and, in a vessel of the extremities, may be followed by gangrenegangrene,
local death of body tissue. Dry gangrene, the most common form, follows a disturbance of the blood supply to the tissues, e.g., in diabetes, arteriosclerosis, thrombosis, or destruction of tissue by injury.
..... Click the link for more information. . 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 arteriosclerosisarteriosclerosis
, general term for a condition characterized by thickening, hardening, and loss of elasticity of the walls of the blood vessels. These changes are frequently accompanied by accumulations inside the vessel walls of lipids, e.g.
..... Click the link for more information. ). A thrombus that breaks off and circulates through the bloodstream is called an embolusembolus
, foreign matter circulating in and obstructing a blood vessel. It may be a portion of a clot that has separated from the wall of a vessel (see thrombosis), a bubble of gas or air (known as an air embolus), a globule of fat, a clump of bacterial matter, or a clump of
..... Click the link for more information. .

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

thrombosis

[thräm′bō·səs] (medicine) Formation of a thrombus.

thrombosis

1. the formation or presence of a thrombus 2. Informal short for coronary thrombosis

thrombosis

[throm-bo´sis] formation, development, or presence of a thrombus; this can happen whenever the flow of blood in arteries or veins is impeded. Many factors can interfere with normal blood flow: heart failure or physical inactivity may retard circulation generally; a change in the shape or inner surface of a vessel wall may impede blood flow, as in atherosclerosis; a mass may grow inside the body and exert pressure on a vessel; the vessel wall may be injured and roughened by an accident, surgery, a burn, cold, inflammation, or infection; or the blood may thicken in reaction to the presence of a foreign serum or snake venom. adj., adj thrombot´ic.
Sometimes a thrombus detaches itself from the wall and is carried along by the bloodstream. Such a clot is called an embolus, and the condition is known as embolism. A thrombus may form in the heart chambers, such as after coronary thrombosis (see below) at the place where the wall of the heart is weakened, or in the dilated atria in a case of stenosis" >mitral stenosis. Because blood normally flows more slowly through the veins than through the arteries, thrombosis is more common in veins than in arteries.Venous Thrombosis. This occurs most often in the legs or pelvis; it may be a complication of phlebitis, result from injury to a vein, or occur with prolonged bed rest. The symptoms—a feeling of heaviness, pain, warmth, or swelling in the affected part, and sometimes chills and fever—do not necessarily indicate its severity. Immediate medical attention is necessary in any case. Under no circumstances should the affected limb be massaged.

In thrombosis of superficial veins, bed rest with legs elevated and application of heat to the affected area may be all that is necessary. In thrombosis of deep veins, the affected part must be immobilized to prevent the clot from spreading or turning into an embolus, and anticoagulant drugs may be given. With proper treatment, recovery occurs within a short time unless an embolism develops. Practice management guidelines for venous thromboembolism in trauma patients note that a filter" >vena cava filter should be considered in patients at high risk who are not candidates for anticoagulants.Prevention of Venous Thrombosis. Immobility is a prime factor in the development of thrombosis; hence, all patients should be mobilized as soon as possible after surgery or an illness that requires bed rest or produces paralysis. Those who cannot get out of bed should follow an exercise routine involving either active or passive motion of the extremities. dehydration also plays a role in the development of thrombosis, and the patient should be kept well hydrated. The use of sequential compression devices, such as graded elastic stockings or automated devices providing intermittent compression to the legs, are widely used and accepted, but there are few clinical studies related to their use. They probably play a role in the prevention of stasis and should be combined with other methods to prevent thromboembolism. Clinical guidelines also support the use of low molecular weight heparin for patients at high risk when the bleeding risk is not considered a problem.Arterial Thrombosis. The main types of arterial thrombosis are related to arteriosclerosis, although thrombosis can also result from infection or from injury to an artery. Arteriosclerosis may be hereditary or may be brought on by diabetes mellitus. Coronary thrombosis, arterial thrombosis in a coronary artery, is a complication of coronary atherosclerosis. A thrombus in one of these arteries will block part of the blood supply to the heart muscle and cause severe myocardial infarction" >myocardial infarction, which is a medical emergency. Cerebral thrombosis is arterial thrombosis in one of the cerebral arteries; the thrombus obstructs the supply of blood to the brain and results in stroke syndrome. Causes include hardening of the cerebral arteries, hypertension, complications of syphilis or other infections, dehydration, diabetes mellitus, or a violent injury.

In advanced cases of arteriosclerosis" >arteriosclerosis, a thrombus may fill up whatever channel remains through a vessel, completely blocking off circulation and causing gangrene. This occurs most frequently in arteries of the legs and is called peripheral thrombosis. The onset, often sudden, is characterized by either a tingling feeling or numbness and coldness in the limb. Pain is not always present. Immediate treatment with anticoagulants is necessary to discourage clotting. If this is not effective, surgery may be required. This condition is most common in the elderly and in diabetics. There are now methods of treatment that may save the limb, such as surgical removal of a thrombus or embolus, or surgery of blood vessels to remove old, narrowed, or deteriorated vessels and replace them with grafts.cerebral thrombosis arterial thrombosis of a cerebral vessel, which may cause stroke syndrome; see also thrombosis" >thrombosis.coronary thrombosis arterial thrombosis in a coronary artery, which may cause myocardial infarction. See also thrombosis" >thrombosis.deep venous thrombosis (DVT) thrombosis" >venous thrombosis of one or more of the deep veins of the lower limb, characterized by swelling, warmth, and erythema; it is frequently a precursor of a embolism" >pulmonary embolism. See also thrombosis" >thrombosis.venous thrombosis phlebothrombosis.

throm·bo·sis

, pl.

throm·bo·ses

(throm-bō'sis, -sēz), 1. Formation or presence of a thrombus. 2. Clotting within a blood vessel that may cause infarction of tissues supplied by the vessel. [G. thrombōsis, a clotting, fr. thrombos, clot]

thrombosis

(thrŏm-bō′sĭs)n. pl. thrombo·ses (-sēz) The formation, presence, or development of a thrombus.

thrombosis

The formation of one or more blood clots or thrombi. See Coronary thrombosis, Deep vein thrombosis, Effort thrombosis, Late-stent thrombosis, Protein C deficiency, Pulmonary thromboembolism.

throm·bo·sis

, pl. thromboses (throm-bō'sis, -sēz) Formation or presence of a thrombus; clotting within a blood vessel that may cause infarction of tissues supplied by the vessel. [G. thrombōsis, a clotting, fr. thrombos, clot]

thrombosis

Clotting of blood within an artery or vein so that the blood flow is reduced or impeded. If the vessel is supplying a vital part, such as the heart muscle or the brain, and the thrombosis cuts off the flow, the result may be fatal. Thrombosis of arteries supplying limbs or organs may lead to GANGRENE. See also CORONARY THROMBOSIS and CEREBRAL THROMBOSIS.

thrombosis

the formation of a clot of blood in a blood vessel.

Thrombosis

Formation of a clot in the blood that either blocks, or partially blocks a blood vessel. The thrombus may lead to infarction, or death of tissue, due to a blocked blood supply.Mentioned in: Arterial Embolism, Coagulation Disorders, Coronary Stenting, Deep Vein Thrombosis, Gangrene, Hypercoagulation Disorders, Pulmonary Embolism

throm·bo·sis

, pl. thromboses (throm-bō'sis, -sēz) 1. Formation or presence of a thrombus. 2. Clotting within a blood vessel that may cause infarction of tissues supplied by vessel. [G. thrombōsis, a clotting, fr. thrombos, clot]

Patient discussion about thrombosis

Q. How can I prevent blood clots? I am 45 years old and am supposed to go on a business trip overseas. The flight itself is 12 hours long and then I have to continue traveling by bus. Could this cause me to have blood clots? If so, how can I prevent it?A. Always walk as much as you can on the plane. Also, rotate your ankels in circles. Sometimes try to use your ankels and make the alphabet with them. Have fun..

Q. Are long flights dangerous? I'm flying next week to my vacation, and the flight is going to be rather long (almost 16 hours non-stop). Several years ago, my 75 years-old aunt had blood clot in her lung after a flight of similar length. I also heard that during flight the blood in the legs clots and that it can cause after that problems with the lungs and breathing.Does this mean it's dangerous for me to fly? Should I change my ticket to shorter connection flights?A. Do other relatives of yours have blood clotting problems too, like your aunt? You should tell a doctor about the problem your aunt had and ask if it's genetic.

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REFERENCES

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Patient discussion about thrombosis

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Synonyms for thrombosis

noun blood clot

Synonyms

Words related to thrombosis

noun the formation or presence of a thrombus (a clot of coagulated blood attached at the site of its formation) in a blood vessel

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