Trombose e embolia - Patologia geral - Medicina veterinária

Summary

This video explains the process of thrombosis, focusing on the formation of blood clots, known as thrombi, and the underlying mechanisms that lead to their development. The presenter discusses Virchow's Triad, which includes endothelial injury, disturbed blood flow, and hypercoagulability, all of which contribute to clot formation. Various types of thrombi are described, including arterial and venous clots, and the concept of embolism, where parts of a clot travel to other areas in the body. The video also touches on different types of emboli, such as fat, gas, and neoplastic emboli, and their effects on the body.

Takeaways

• 😀 The circulatory system is essential for blood flow and its uninterrupted circulation, with hemostasis being the body's defense mechanism against blood loss.
• 😀 Hemostasis involves the interaction between endothelial cells, platelets, and coagulation factors to prevent excessive bleeding.
• 😀 Thrombosis occurs when an inappropriate clot (thrombus) forms, typically due to disturbances in the blood's flow or excessive clotting.
• 😀 The Virchow's Triad consists of three factors that predispose the body to thrombosis: endothelial injury, altered blood flow, and hypercoagulability.
• 😀 Endothelial injury disrupts normal blood flow and causes the body to produce pro-coagulant substances, increasing the likelihood of thrombus formation.
• 😀 Altered blood flow, such as turbulent or slow blood flow, increases the risk of thrombosis by causing platelets to come in contact with the vessel walls.
• 😀 Hypercoagulability refers to an increase in clotting factors or a decrease in fibrinolytic factors, which can lead to excessive clotting and thrombosis.
• 😀 Thrombi can be classified into arterial and venous types, with arterial thrombi often being mural (not obstructing blood flow), while venous thrombi are typically occlusive.
• 😀 Thrombi can appear in different colors: white thrombi (arterial) with fewer red blood cells and red thrombi (venous) with more red blood cells.
• 😀 The process of thrombosis can result in embolism, where parts of the thrombus break off and travel to other vessels, potentially causing infraction (tissue death) in organs like the lungs, kidneys, and brain.

Q & A

What is hemostasis and why is it important for the body?

Hemostasis is the body's process to prevent excessive blood loss by controlling bleeding through the interaction of endothelial cells, platelets, and coagulation factors. It is essential for maintaining the circulatory system's stability and preventing uncontrolled bleeding or blood clot formation.

What is thrombosis and how does it occur?

Thrombosis is the formation of an inappropriate blood clot (thrombus) within a blood vessel. It can happen when there are disruptions in hemostasis, such as endothelial injury, abnormal blood flow, or a hypercoagulable state, leading to excessive clot formation.

What are the three factors of Virchow's Triad that predispose to thrombosis?

The three factors of Virchow's Triad are endothelial injury, abnormal blood flow (such as turbulence or stasis), and hypercoagulability, which together or independently increase the risk of thrombus formation.

How does endothelial injury contribute to thrombosis?

Endothelial injury leads to the loss of anticoagulant substances normally produced by the endothelium, causing an increase in pro-coagulant factors. This alteration in the balance of coagulation triggers thrombus formation.

What is laminar blood flow, and how does it affect thrombosis risk?

Laminar blood flow is the smooth flow of blood where formed elements, like platelets and red blood cells, run in the center of the vessel, and plasma flows on the periphery. Disruptions to this flow, such as turbulence or stasis, increase the chances of platelets coming into contact with the vessel wall, raising the risk of thrombosis.

What role does reduced blood flow play in thrombosis?

Reduced blood flow, whether local or systemic, can lead to the accumulation of coagulation factors. In conditions like heart failure or heart disease, where blood flow is decreased, the lack of movement allows clotting factors to activate and promote thrombus formation.

What is hypercoagulability, and what causes it?

Hypercoagulability refers to a condition where the blood is more prone to clotting due to an increase in pro-coagulant factors or a decrease in fibrinolytic factors. This condition can be caused by factors like inflammation, increased platelet concentration, or disorders that elevate coagulation factors.

How can thrombosis be classified?

Thrombosis can be classified into two types: arterial thrombosis, which is usually non-occlusive and adheres to the vessel wall, and venous thrombosis, which tends to be occlusive and can block blood flow entirely.

What are the differences between white and red thrombi?

White thrombi are typically found in arteries and consist mainly of platelets without red blood cells, while red thrombi, typically found in veins, contain a mix of platelets and red blood cells, giving them a red appearance. The presence of red blood cells forms the characteristic tail of a red thrombus.

What is disseminated intravascular coagulation (DIC), and how does it occur?

Disseminated intravascular coagulation (DIC) is a pathological process where widespread clotting occurs in the microcirculation, typically in small vessels like capillaries and venules. This can be triggered by severe conditions such as septicemia, autoimmune diseases, or infections, leading to the consumption of clotting factors and causing hemorrhage.

What are emboli, and how are they related to thrombosis?

Emboli are fragments of a thrombus or foreign bodies that travel through the bloodstream and can lodge in smaller blood vessels, blocking circulation. These can result in conditions like infarction, where tissues become necrotic due to the loss of blood flow.

What types of emboli can occur other than thromboemboli?

Besides thromboemboli, other types of emboli include bacterial emboli (from infections), fat emboli (from fractures), air emboli (due to air injected into the bloodstream), neoplastic emboli (from cancer cells), and parasitic emboli (from infections like parasitic infestations).