Chapter 27: Thrombosis 1: Pathogenesis and Diagnosis

Thrombosis 1: Pathogenesis and Diagnosis examines the distinct pathways leading to arterial and venous obstructions, highlighting how arterial events are primarily driven by atherosclerosis and vessel wall injury, whereas venous issues are often influenced by the components of Virchow’s triad: reduced blood flow, increased blood thickness, and vessel damage. The discussion incorporates the emerging understanding of inflammation's impact, specifically how neutrophil extracellular traps and altered levels of clotting factors contribute to clot formation. A significant portion of the material is dedicated to hereditary thrombophilia, detailing common genetic predispositions such as the factor V Leiden mutation—which results in resistance to activated protein C—and rarer deficiencies in protein C, protein S, and antithrombin. Furthermore, the text identifies a wide range of acquired risks, including surgical recovery, prolonged immobility, cancer, and the use of oestrogen-based medications. It also covers complex immune-mediated conditions like antiphospholipid syndrome and heparin-induced thrombocytopenia. To aid in clinical management, the chapter outlines diagnostic strategies for deep vein thrombosis and pulmonary embolism, emphasizing the utility of the Wells clinical prediction rule and D-dimer testing to rule out events, alongside definitive imaging tools like compression ultrasound and various forms of angiography. Finally, it addresses the morbidity associated with post-thrombotic syndrome, where damaged venous valves lead to chronic swelling and skin changes.