WordNet

smear with blood, as in a hunting initiation rite, where the face of a person is smeared with the blood of the kill
temperament or disposition; "a person of hot blood"
people viewed as members of a group; "we need more young blood in this organization"
the fluid (red in vertebrates) that is pumped through the body by the heart and contains plasma, blood cells, and platelets; "blood carries oxygen and nutrients to the tissues and carries away waste products"; "the ancients believed that blood was the sea
change from a liquid to a thickened or solid state; "coagulated blood" (同)coagulate
a lump of material formed from the content of a liquid (同)coagulum
cause to change from a liquid to a solid or thickened state (同)coagulate

PrepTutorEJDIC

『血』,『血』液 / 流血(bloodshed);殺人 / 気質,気性,血気,血潮 / 『血統』,血縁(kinship);生まれ,家柄;《the~》王家の血統 / (人種・出身国の)系 / 〈人〉‘に'初めての経験をさせる / 〈猟犬〉‘に'初めて獲物を血を味わわせる
ゼリー状の固まり / 〈血液・ミルクなどが〉凝固する / …'を'凝固させる
純血の,純種の / 《複合語を作って》「…の血(性質)を持った」の意を表す
centiliter[s]

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/10/22 00:01:56」(JST)

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"Clot" redirects here. For other uses, see Clot (disambiguation).

Not to be confused with Embolism.

Micrograph showing a thrombus (center of image) within a blood vessel of the placenta. H&E stain.

Blood clot diagram.

A thrombus (Greek: θρόμβος), or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system (i.e. clotting factors). A thrombus is normal in cases of injury, but pathologic in instances of thrombosis.

Mural thrombi are thrombi adherent to the vessel wall. They are not occlusive and affect large vessels, such as heart and aorta. Grossly they appear grey-red with alternating light and dark lines (lines of Zahn) which represent bands of fibrin (lighter) with entrapped white blood cells and red blood cells (darker).

Pathophysiology

Specifically, a thrombus is the inappropriate activation of the hemostatic process in an uninjured or slightly injured vessel. A thrombus in a large blood vessel will decrease blood flow through that vessel (termed a mural thrombus). In a small blood vessel, blood flow may be completely cut-off (termed an occlusive thrombus) resulting in death of tissue supplied by that vessel. If a thrombus dislodges and becomes free-floating, it is termed as an embolus.

Some of the conditions which elevate risk of blood clots developing include atrial fibrillation (a form of cardiac arrhythmia), heart valve replacement, a recent heart attack (also known as a myocardial infarction), extended periods of inactivity (see deep venous thrombosis), and genetic or disease-related deficiencies in the blood's clotting abilities.

Formation

Platelet activation can occur through different mechanisms such as a vessel wall breach that exposes collagen, or tissue factor encryption. The platelet activation causes a cascade of further platelet activation eventually causing the formation of the thrombus.^[1]

Treatment

Blood clot prevention and treatment reduces the risk of stroke, heart attack and pulmonary embolism. Heparin and warfarin are often used to inhibit the formation and growth of existing thrombi; the former binds to and activates the enzyme inhibitor antithrombin III, while the latter inhibits vitamin K epoxide reductase, an enzyme needed to synthesize mature clotting factors.

Recent studies

Recent research shows that chemicals found in certain foods as onions, apples and oranges could help prevent blood clots. Researchers claim that rutin found in black and green teas also could help prevent the formation of clots and therefore could help in future treatments to protect against strokes and heart attacks.^[2]

Presentation

Virchow's triad describes the pathogenesis of thrombus formation:

Endothelial injury (injury to the endothelial cells that line enclosed spaces of the body, such as the inside of blood vessels) (e.g. trauma, atheroma)
Abnormal blood flow (loss of laminar flow resulting from stasis in veins or turbulence in arteries) (e.g. valvulitis, aneurysm)
Hypercoagulability (e.g. leukaemia, Factor V mutation (Leiden))

Disseminated intravascular coagulation (DIC) involves widespread microthrombi formation throughout the majority of the blood vessels. This is due to excessive consumption of coagulation factors and subsequent activation of fibrinolysis using all of the body's available platelets and clotting factors. The end result is hemorrhaging and ischaemic necrosis of tissue/organs. Causes are septicaemia, acute leukaemia, shock, snake bites, fat emboli from broken bones, or other severe traumas. DIC may also be seen in pregnant females. Treatment involves the use of fresh frozen plasma to restore the level of clotting factors in the blood, platelets and heparin to prevent further thrombi formation.

Thoracic aortic thrombus is a rare pathology that usually originates from an atherosclerotic aortic wall lesion or an aortic aneurysm and is a potential source of visceral, cerebral and peripheral embolism^[3]^[4] .

Prognosis

Thrombus formation can have one of five outcomes: propagation, embolization, dissolution, organization and organization with recanalization.^[5]

Propagation of a thrombus occurs towards the direction of the heart. This means that it is anterograde in veins or retrograde in arteries.
Embolization occurs when the thrombus breaks free from the vascular wall and becomes mobile. A venous emboli (most likely from deep venous thrombosis in the lower extremities) will travel through the systemic circulation, reach the right side of the heart, and travel through the pulmonary artery resulting in a pulmonary embolism. On the other hand, arterial thrombosis resulting from hypertension or atherosclerosis can become mobile and the resulting emboli can occlude any artery or arteriole downstream of the thrombus formation. This means that cerebral stroke, myocardial infarction, or any other organ can be affected.
Dissolution occurs when fibrinolytic mechanisms break up the thrombus and blood flow is restored to the vessel. This may be aided by drugs (for example after occlusion of a coronary artery). The best response to fibrinolytic drugs is within a couple of hours, before the fibrin meshwork of the thrombus has been fully developed.
Organization and recanalization involves the ingrowth of smooth muscle cells, fibroblasts and endothelium into the fibrin-rich thrombus. If recanalization proceeds it provides capillary-sized channels through the thrombus for continuity of blood flow through the entire thrombus but may not restore sufficient blood flow for the metabolic needs of the downstream tissue.

References

^ Furie, Bruce; Furie, Barbara (2008). "Mechanisms of Thrombus Formation". The New England Journal of Medicine 359 (9). doi:10.1056/NEJMra0801082. PMID 18753650. http://www.nejm.org/doi/full/10.1056/NEJMra0801082.
^ Prescott, Bonnie. "Flavonoid compound can prevent blood clots". Harvard Gazette. http://news.harvard.edu/gazette/story/2012/05/flavonoid-compound-can-prevent-blood-clots/. Retrieved 27 May 2012.
^ Fueglistaler, P; Wolff T, Guerke L, Stierli P, Eugster T (2005). "Endovascular stent graft for symptomatic mobile thrombus of the thoracic aorta.". J Vasc Surg 42 (4): 781-783. PMID 16242568.
^ Ungprasert, P; Ratanapo S, Cheungpasitporn W. "Management in Thoracic Aorta Mural Thrombi: Evidence Based Medicine and Controversy.". Emergency Medicine 1 (e104). doi:10.4172/2165-7548.1000e104. http://dx.doi.org/10.4172/2165-7548.1000e104.
^ Robbins Basic Pathology; ISBN 978-1-4160-2973-1

External links

Look up thrombus or clot in Wiktionary, the free dictionary.

Treatment and Symptoms of Blood Clots -- MDhealthnetwork.org, Medical Information Resource, 1999
North American Thrombosis Forum - NATF is a nonprofit organization dedicated to promoting thrombosis research, prevention and education, public policy, and advocacy outreach.
Muscle Relaxing Drugs Can Reduce Lethal Blood Clots
Air Pollution Triggers Blood Clots - US Study.
The National Alliance for Thrombosis and Thrombophilia - has extensive stories from patients and family members on living with Thrombosis and Thrombophilia, assembled frequently asked questions and created publications addressing specific blood clot issues.

UpToDate Contents

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1. 外傷に伴う凝固障害 coagulopathy associated with trauma
2. 頸動脈内膜剥離術および頸動脈ステント留置術の麻酔 anesthesia for carotid endarterectomy and carotid stenting
3. Acute mesenteric arterial occlusion
4. 急性虚血性脳卒中に対する再灌流療法 reperfusion therapy for acute ischemic stroke
5. 成人における選択的脊椎手術のための麻酔 anesthesia for elective spine surgery in adults

English Journal

Dual antiplatelet treatment in patients candidates for abdominal surgery.

Illuminati G, Ceccanei G, A Pacilè M, Pizzardi G, Palumbo P, Vietri F.AbstractWith the increasing diffusion of percutaneous interventions (PCI), surgeons are often faced with the problem of operating on patients under dual antiplatelet treatment. Replacing dual antiplatelet regiment with low molecular weight heparin may expose to the abrupt thrombosis of coronary stent and massive myocardial infarction. The purpose of this study was to test the hypothesis that abdominal operations can be safely performed under dual antiplatelet treatment. Eleven patients underwent 5 colectomies, 3 nefrectomies, 2 gastrectomies and 1 hysterectomy under aspirin and plavix without any significant perioperative hemorrhage. These preliminary results show that abdominal operations can be safely performed under dual antiplatelet regimen.
Annali italiani di chirurgia.Ann Ital Chir.2014;83:291-4.
With the increasing diffusion of percutaneous interventions (PCI), surgeons are often faced with the problem of operating on patients under dual antiplatelet treatment. Replacing dual antiplatelet regiment with low molecular weight heparin may expose to the abrupt thrombosis of coronary stent and ma
PMID 23103787

Fulvestrant for advanced breast cancer: A meta-analysis.

Al-Mubarak M, Sacher AG, Ocana A, Vera-Badillo F, Seruga B, Amir E.SourceDivision of Medical Oncology and Hematology, Princess Margaret Hospital and Department of Medicine, University of Toronto, Toronto, Canada; Ministry of Higher Education, Riyadh, Saudi Arabia.
Cancer treatment reviews.Cancer Treat Rev.2013 Nov;39(7):753-8. doi: 10.1016/j.ctrv.2013.03.004. Epub 2013 Jun 10.
BACKGROUND: Fulvestrant is an endocrine agent which degrades the estrogen receptor, thereby downregulating its signaling. Trials of fulvestrant are limited by inconsistent study populations and drug dosing. The optimal use of fulvestrant in advanced breast cancer is therefore unclear.METHODS: A syst
PMID 23764179

Japanese Journal

不自然なくも膜下出血分布から破裂動脈瘤を誤診した多発脳動脈瘤の1例

小野元,小林敦,神野崇生,小菅康史,田中雄一郎
Japanese Journal of Neurosurgery 23(2), 150-155, 2014
不自然なくも膜下出血分布を呈し, 破裂動脈瘤の診断を誤った多発脳動脈瘤症例を経験した. 症例は32歳女性, 頭痛を主訴に来院した. CTで右側シルビウス裂と不連続に脳幹前面に出血を認め, 造影CTでは右側内頚後交通動脈瘤と脳底動脈窓形成部動脈瘤を認めた. 出血分布の左右差から右側内頚後交通動脈瘤を破裂源と考え, 急性期にクリッピング術を行った. しかし初回手術時に破裂源の動脈瘤であるかどうかの判 …
NAID 130003397696

毛包炎により発症した頸部Mondor病例

石田芳也,寒風澤知明,高原幹 [他],原渕保明
耳鼻咽喉科臨床 107(4), 323-325, 2014
… Ultrasonographic and CT examinations showed enlargement of a cutaneous vein with a blood clot. …
NAID 130003395646