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This Sqadia video deals with the topic of pathology that is Hemorrhagic Disorders. Hemostasis or haemostasis is a process which causes bleeding to stop, meaning to keep blood within a damaged blood vessel (the opposite of Hemostasis is hemorrhage). It is the first stage of wound healing. Fundamental Steps in Haemostasis are Primary Haemostasis ( Interaction between platelets and damaged vascular endothelium to form an unstable platelet plug at the site of injury), Secondary Haemostasis ( Process of blood coagulation, which is focused on the generation of thrombin which in turn converts soluble fibrinogen to insoluble fibrin and forms a stable clot) and Fibrinolysis ( Fibrinolysis involves breakdown of fibrin clot to re-establish vascular patency and normal blood flow).
Introduction to Hemorrhagic Disorders
Defects in Hemostasis that Lead to an Increased susceptibility to bleeding (slso known as Hemorrhagic Diathesis). They are caused either by platelet disorders (Primary hemostasis defect). To form a firm platelet plug, it is necessary to have healthy blood vessels, VWF and sufficient and well-functional platelets. Diseases of these three players cause primary hemostatic disorders. In Vessel Abnormalities increased vascular fragility and Manifest by petechial hemorrhages of skin/mucous membranes. Bleeding Disorders-Vessel Wall Abnormalities causes are Infections, Drug reactions and Senile purpura & Cushing´s Syndrome.
Disorders of Primary Hemostasis
Disorders of platelet function are as follows: Disorders of platelet adhesion (von Willebrand disease, Bernard-Soulier syndrome) Disorders of aggregation (Glanzmann thrombasthenia) Disorders of secretion and Disorders of thromboxane synthesis. Chronic Immune Thrombocytopenia was previously known as idiopathic thrombocytopenic purpura. Antiplatelet antibodies accelerate platelet destruction and simultaneously prevent the release in mild to serious bleeding. It is more frequent between 20 to 40 years, common in females. Treatment includes platelet transfusions, corticosteroids (prednisolone 1-2 mg/kg for 2 to 4 weeks and reduced slowly) to induced remission and splenectomy is indicated in adults who did not respond to corticosteroids. Acute ITP is believed to be a consequence of a disordered immune response during recovery from a viral infection that evokes the formation of antibodies that cause platelet destruction. Spontaneous aggregation of platelets and activation of coagulation in small blood vessels. Platelets are consumed in the aggregation process and bind vWF. Platelet-vWF complexes form small blood clots circulate in the blood vessels and cause shearing and rupture of RBC’s.
Disorders of Secondary Hemostasis
Characteristics in disorders of secondary hemostasis includes Deficiencies of plasma clotting factors of coagulation cascade, Bleeding from larger vessels, Hemarthroses, Hematomas, Large ecchymoses, Extensive bleeding with trauma, BT or platelet count not affected, PT abnormalities (fibrinogen, FII,V,VII,X), APTT(all factors deficiency except FVII,XIII), and Thrombin time ( deficiency of fibrinogen). Hemophilia A, also called factor VIII (FVIII) deficiency or classic hemophilia, is a genetic disorder caused by missing or defective factor VIII, a clotting protein. Although it is passed down from parents to children, about 1/3 of cases are caused by a spontaneous mutation, a change in a gene. Hemophilia is a rare bleeding disorder that results from reduced levels or lack of clotting factor VIII (FVIII; hemophilia A) or IX (FIX; hemophilia B). Normal blood clotting is a complex process that involves as many as 20 blood proteins called clotting factors. Both vitamin K-1 and vitamin K-2 produce proteins that help the blood to clot. Blood clotting or coagulation prevents excessive bleeding internally and externally. While vitamin K deficiency is rare, it means a person's body cannot produce enough of these proteins, increasing the risk of excessive bleeding.
Combined Primary and Secondary Hemostatic Defects
Von Willebrand disease (VWD) is a genetic disorder caused by missing or defective von Willebrand factor (VWF), a clotting protein. VWF binds factor VIII, a key clotting protein, and platelets in blood vessel walls, which help form a platelet plug during the clotting process. Disseminated intravascular coagulation (DIC) is characterized by systemic activation of blood coagulation, which results in generation and deposition of fibrin, leading to microvascular thrombi in various organs and contributing to multiple organ dysfunction syndrome (MODS). Coagulopathy of Liver Disease Failure to produce clotting factors II, V, VII and IX. And Failure of the diseased liver to clear activated clotting factors. Degree of hypersplenism and thrombocytopaenia often adds to the coagulopathy, especially if disseminated intravascular coagulation (dic) also co-exists. The degree of coagulopathy is measure of severity of liver disease and of patient prognosis. Routine correction of coagulopathy is therefore NOT indicated in less active bleeding or planned interventions require it.