Virchow's triad or the triad of Virchow () describes the three broad categories of factors that are thought to contribute to

thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thro ...

. *

Hypercoagulability Thrombophilia (sometimes called hypercoagulability or a prothrombotic state) is an abnormality of blood coagulation that increases the risk of thrombosis (blood clots in blood vessels). Such abnormalities can be identified in 50% of people who ...

Hemodynamic Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously mo ...

changes (stasis, turbulence) *

Endothelial The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...

injury/dysfunction It is named after the renowned

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

physician A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...

Rudolf Virchow Rudolf Ludwig Carl Virchow (; or ; 13 October 18215 September 1902) was a German physician, anthropologist, pathologist, prehistorian, biologist, writer, editor, and politician. He is known as "the father of modern pathology" and as the founder ...

(1821-1902). However, the elements comprising Virchow's triad were not proposed by Virchow. Neither did he ever suggest a triad to describe the pathogenesis of venous thrombosis. In fact, it was not until decades after Virchow's death that a consensus was reached proposing that thrombosis is the result of alterations in blood flow, vascular endothelial injury, or alterations in the constitution of the blood. Still, the modern understanding of the factors leading to embolism is similar to the description provided by Virchow. Virchow's triad remains a useful concept for clinicians and pathologists alike in understanding the contributors to thrombosis. __TOC__

The triad

The triad consists of three components:

History

The origin of the term "Virchow's Triad" is of historical interest, and has been subject to reinterpretation in recent years. While both Virchow's and the modern triads describe

, the previous triad has been characterized as "the consequences of thrombosis", and the modern triad as "the causes of thrombosis". Rudolf Virchow elucidated the etiology of

pulmonary embolism Pulmonary embolism (PE) is a blockage of an pulmonary artery, artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include dyspnea, shortness of breath, chest pain p ...

, whereby

thrombi A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of c ...

occurring within the

veins Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

, particularly those of the extremities, become dislodged and migrate to the pulmonary vasculature. He published his description in 1856. In detailing the

pathophysiology Pathophysiology ( physiopathology) – a convergence of pathology with physiology – is the study of the disordered physiological processes that cause, result from, or are otherwise associated with a disease or injury. Pathology is the ...

surrounding pulmonary embolism, he alluded to many of the factors known to contribute to venous thrombosis. While these factors had already been previously established in the medical literature by others, for unclear reasons they ultimately became known as Virchow's triad. This

eponym An eponym is a person, a place, or a thing after whom or which someone or something is, or is believed to be, named. The adjectives which are derived from the word eponym include ''eponymous'' and ''eponymic''. Usage of the word The term ''epon ...

did not emerge in the literature until long after Virchow's death. One estimate of the first use of the phrase dates it to the early 1950s. Although the concept of the triad is usually attributed to Virchow, he did not include endothelial injury in his description. This has been attributed to a dispute Virchow had with

Jean Cruveilhier Jean Cruveilhier (; 9 February 1791 – 7 March 1874) was a French anatomist and pathologist. Academic career Cruveilhier was born in Limoges, France. As a student in Limoges, he planned to enter the priesthood. He later developed an inte ...

, who considered local trauma of primary importance in the development of pulmonary artery thrombosis.Aschoff L. Thrombosis, in Lectures on Pathology. New York, Paul B. Hoeber, Inc., 1924, pp 253-278.

References

{{Bleeding and clotting disorders, us=y Hematology Rudolf Virchow Medical triads