Category Archives: Haemostasis

Learning outcome Describe the causes, pathophysiology, clinical and laboratory features of disseminated intravascular coagulation (DIC) Pathophysiology Disseminated intravascular coagulation (DIC) is a complex haemorrhagic disorder caused by uncontrolled activation of the coagulation cascade, usually upon inappropriate release of tissue factor (TF). Other factors such as bacterial components, snake venom and products of conception may alsoContinue reading “Disseminated intravascular coagulation (DIC)”

Learning outcome List the vitamin K dependant factors Explain the mechanism underlying vitamin K deficiency and bleeding Explain the role of warfarin as an anticoagulant and its action on the vitamin K redox cycle Describe the causes, clinical and laboratory features of vitamin K deficiency and warfarin overdose Vitamin K dependant factors and the vitaminContinue reading “Vitamin K deficiency, liver disease & warfarin overdose”

Learning outcome Describe the pathophysiology, inheritance, clinical and laboratory features of Haemophilia A and B Haemophilia A Pathophysiology Haemophilia A is a condition caused by reduced FVIII activity due to defective synthesis of the FVIII molecule. Its prevalence is estimated at 1 in 5,000 males. No significant geographical variation in its prevalence is reported. The condition isContinue reading “Haemophilia A & B”

Learning outcome Describe the pathophysiology, inheritance, clinical and laboratory features of von Willebrand disease Introduction The coagulation cascade consists of many interacting proteins that serve as activating proteases and co-factors that amplify the reaction. Functional mutations have been identified in nearly all of the proteins within the coagulation cascade, that results in an heritable bleedingContinue reading “von Willebrand’s disease (vWD)”

Learning outcome Describe the pathogenesis, clinical and laboratory feature of immune thrombocytopenia purpura. Pathophysiology Immune thrombocytopenia purpura (ITP) is a condition characterised by low platelet counts resulting from immune destruction of platelets. Auto-antibodies to platelet antigens develop (similar to that seen with red cells in autoimmune haemolytic anaemia) and coat the patient’s platelets that are subsequently removed by the splenicContinue reading “Immune thrombocytopenia purpura (ITP)”

Learning outcome Distinguish the use of common laboratory tests (Platelet count, APTT, PT, TT) to assess abnormalities of the coagulation cascade Clinical assessment and classification of bleeding disorders The clinical assessment of a patient with suspected bleeding disorder should include evaluation of; Age of onset and gender Extent and type of bleeding – skin, mucosal,Continue reading “Clinical and laboratory assessment of bleeding”

Learning outcomes Explain the physiological process of haemostasis involving the blood vessel, platelet and coagulation factors List the coagulation factors that are associated with the intrinsic and extrinsic pathways of coagulation Introduction Haemostasis is the process that occurs when there is vascular injury. It is a complex dynamic process that involves interaction between the endotheliumContinue reading “Normal haemostasis”