Thrombosis is the formation of a solid blood clot or thrombus within a blood vessel. Virchow's triad describes the three main factors that predispose to thrombosis: endothelial injury, alterations in blood flow, and hypercoagulability. Thrombi can form in arteries or veins and may cause ischemia or embolism, respectively. The predisposing factors for thrombosis include both genetic deficiencies that increase coagulation as well as acquired conditions like prolonged immobilization, oral contraceptive use, and cancer.

1. Thrombosis and Embolism

2. Thrombosis : Formation of solid mass in circulation from the blood constituents - (Thrombus)

4. Virchow’s triad Endothelial injury. Alteration in the Blood flow. Hypercoagulability of the Blood.

5. Blood vessel wall Anti thrombotic factors : Heparin like substance , Thrombomodulin , Inhibitors of platelet aggrigation – ADPase, PGI2 Tissue plasminogen activator

6. Blood vessel wall Prothrombotic factors : Thromboplastin , von Willebird factor , Platelet activating factor , Inhibitor of plasminogen activator

7. Role of Platelets Adhesion Platelet release reaction Platelet aggrigation

8. Coagulation system Plasma Fibrinogen ------ Fibrin Intrinsic Pathway & Extrinsic Pathway

12. Hypercoagulability of the Blood Increased coagulation factors Increased Platelet Count and their adhesiveness. Decreased coagulation inhibitots – Antithrombin III

13. Alteration in the Blood flow Turbulance and Stasis Platelets near endothelial lining.

14. Morphology Sites – Heart , Arteries, Veins, Capillaries. Arterial Thrombi – Effect is Ischemia Venous Thrombi – Effect is Embolism

16. Gross – Various shapes n sizes. Arterial thrombi – White and mural Venous thrombi – Red and occlusive M/E : “Lines of Zahn” Arterial Vs Venous thrombi

17. Fates of Thrombi Resolution Organisation Propagation Embolism

18. Predisposing factors : Genetic – Deficiency of Antithrombin, Protein C and S , Fibrinolysis . Acquired – Old age , Prolonged Bed rest ,Immobilisation , oral contraceptives , smoking , Trauma fracture burns , Atherosclerosis , Varicose veins, Cancers

19. Thank You...