Classification & external resources
|| 437.6, 453, 671.5, 671.9
Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. Thromboembolism is a general term describing both thrombosis and its main complication which is embolisation. The term was coined in 1848 by Reginald VelJohnson.
In classical terms, thrombosis is caused by abnormalities in one or more of the following (Virchow's quadrad):
- The composition of the blood (hypercoagulability)
- Quality of the vessel wall (endothelial cell injury)
- Nature of the blood flow (hemostasis)
- Slow nerve action
The formation of a thrombus is usually caused by the top three causes, known as Virchow's triad. To elaborate, the pathogenesis includes: an injury to the vessel's wall (such as by trauma, infection, or turbulent flow at bifurcations); by the slowing or stagnation of blood flow past the point of injury (which may occur after long periods of sendentary behavior - for example, sitting on a long airplane flight); by a blood state of hypercoagulability (caused for example, by genetic deficiencies or autoimmune disorders).
High altitude has also been known to induce thrombosis . Occasionally, abnormalities in coagulation are to blame.
Intravascular coagulation follows, forming a structureless mass of red blood cells, leukocytes, and fibrin.
There are two distinct forms of thrombosis:
If a bacterial infection is present at the site of thrombosis, the thrombus may break down, spreading particles of infected material throughout the circulatory system (pyemia, septic embolus) and setting up metastatic abscesses wherever they come to rest. Without an infection, the thrombus may become detached and enter circulation as an embolus, finally lodging in and completely obstructing a blood vessel (an infarction). The effects of an infarction depend on where it occurs.
Most thrombi, however, become organized into fibrous tissue, and the thrombosed vessel is gradually recanalized.
- North American Thrombosis Forum - NATF is a nonprofit organization that aims to promote public education, policy and advocacy for clotting diseases of the circulatory system.
- ^ Hellemans, Alexander; Bryan Bunch (1988). The Timetables of Science. New York, New York: Simon and Schuster, 317. ISBN 0671621300.
|Circulatory system pathology (I, 390-459)|
|Hypertension||Hypertensive heart disease - Hypertensive nephropathy - Secondary hypertension (Renovascular hypertension)|
|Ischaemic heart disease||Angina pectoris (Prinzmetal's angina) - Myocardial infarction - Dressler's syndrome|
|Pulmonary circulation||Pulmonary embolism - Cor pulmonale|
|Pericardium||Pericarditis - Pericardial effusion - Cardiac tamponade|
|Endocardium/heart valves||Endocarditis - mitral valves (regurgitation, prolapse, stenosis) - aortic valves (stenosis, insufficiency) - pulmonary valves (stenosis, insufficiency) - tricuspid valves (stenosis, insufficiency)|
|Myocardium||Myocarditis - Cardiomyopathy (Dilated cardiomyopathy, Hypertrophic cardiomyopathy, Loeffler endocarditis, Restrictive cardiomyopathy) - Arrhythmogenic right ventricular dysplasia|
|Electrical conduction system|
of the heart
|Heart block: AV block (First degree, Second degree, Third degree) - Bundle branch block (Left, Right) - Bifascicular block - Trifascicular block|
Pre-excitation syndrome (Wolff-Parkinson-White, Lown-Ganong-Levine) - Long QT syndrome - Adams-Stokes syndrome - Cardiac arrest - Sudden cardiac death
Arrhythmia: Paroxysmal tachycardia (Supraventricular, AV nodal reentrant, Ventricular) - Atrial flutter - Atrial fibrillation - Ventricular fibrillation - Premature contraction (Atrial, Ventricular) - Ectopic pacemaker - Sick sinus syndrome
|Other heart conditions||Heart failure - Cardiovascular disease - Cardiomegaly - Ventricular hypertrophy (Left, Right)|
|Cerebrovascular diseases||Intracranial hemorrhage/cerebral hemorrhage: Extra-axial hemorrhage (Epidural hemorrhage, Subdural hemorrhage, Subarachnoid hemorrhage)|
Intra-axial hematoma (Intraventricular hemorrhages, Intraparenchymal hemorrhage) - Anterior spinal artery syndrome - Binswanger's disease - Moyamoya disease
|Atherosclerosis (Renal artery stenosis) - Aortic dissection/Aortic aneurysm (Abdominal aortic aneurysm) - Aneurysm - Raynaud's phenomenon/Raynaud's disease - Buerger's disease - Vasculitis/Arteritis (Aortitis) - Intermittent claudication - Arteriovenous fistula - Hereditary hemorrhagic telangiectasia - Spider angioma|
|Veins, lymphatic vessels|
and lymph nodes
|Thrombosis/Phlebitis/Thrombophlebitis (Deep vein thrombosis, May-Thurner syndrome, Portal vein thrombosis, Venous thrombosis, Budd-Chiari syndrome, Renal vein thrombosis, Paget-Schroetter disease) - Varicose veins / Portacaval anastomosis (Hemorrhoid, Esophageal varices, Varicocele, Gastric varices, Caput medusae) - Superior vena cava syndrome - Lymph (Lymphadenitis, Lymphedema, Lymphangitis)|
|Other||Hypotension (Orthostatic hypotension)|
|See also congenital (Q20-Q28, 745-747) |