Unit 4 Coagulation 1.0.pptx
Transcript
3.2.1,3.2.2,3.3.3.,4,1 Coagulation 1 Objectives Coagulation Objectives 1. Define hemostasis 1.1 Define hemostasis 2. Response to Blood Vessel Injury: 2.1 Describe the steps when during a blood vessel injury 3. Thr...
3.2.1,3.2.2,3.3.3.,4,1 Coagulation 1 Objectives Coagulation Objectives 1. Define hemostasis 1.1 Define hemostasis 2. Response to Blood Vessel Injury: 2.1 Describe the steps when during a blood vessel injury 3. Thromboembolism 3.1 Define Thromboembolism 4. Coagulation Tests: 4.1 List some coagulation tests 5. Coagulation Factors 5.1 List and describe the 12 coagulation factors Objectives 6. Coagulation pathways 6.1 Describe the 2 coagulation pathways ( intrinsic and extrinsic pathways ) 6.2 List the test used for the intrinsic and extrinsic pathways 6.3 Describe the common pathway 7. Disseminated Intravascular Coagulation (DIC) 7.1 Describe Disseminated Intravascular Coagulation (DIC) 7.2 List the diagnosis blood test for Disseminated Intravascular Coagulation (DIC) Coagulation Tube ( Sodium Citrate) 5 Hemostasis Definition: is a process which causes bleeding to stop. When a vessel is injured: Vessel contracts Platelets are initiated to form a clot Clotting factors convert fibrinogen to fibrin Mechanism of Hemostasis The first step is the vessel contracts The second step is where The platelets plug is formed. Platelets stick together to form a temporary seal to cover the break in the vessel wall. The third and last step is called initiation. Coagulation reinforces the platelet plug with fibrin threads that act as a "molecular glue”. Endothelial cell damage expose a glue – like substance called von Willebrand factor that causes platelets to stick to the damage tissue. Formation of the platelet plug Thromboembolism ( floating clot) Occasionally a clot will not dissolve once healing is complete. It might break away to become a floating clot Treatment involves drug therapy such as streptokinase to dissolve the clot. tissue plasminogen activator (tPA), — a clot- dissolving enzyme., and putting the patient on anticoagulant therapy such heparin Aspirin is a drug that interferes with platelet aggregation and is used to prevent clotting 10 Coagulation tests Prothrombin Time/INR (PT ) – prothrombin is a substance found in blood that when activated is converted to thrombin. INR – International Normalization Ration Partial thromboplastin time(PTT) Fibrinogen – is converted to fibrin Thrombin 11 INR Point of Care testing D – Dimer - is a fibrin degradation product. It is a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. It is so named because it contains two crosslinked D fragments of the fibrin protein. 13 Factor Studies – there are 12 factors eg. A decrease in Factor VIII – hemophilia 14 Clotting factors There are 12 clotting factors that influence the clotting mechanism. Factor I – Fibrinogen Factor II – Prothrombin Factor III – Tissue Thromboplastin Factor IV – Ionized Ca 15 Factor V - Labile factor or proaccelerin Factor VI - Unassigned Factor VII - Stable factor or proconvertin Factor VIII - Antihemophilic factor Factor VIIII - Plasma thromboplastin component, Christmas factor ( Also known as Hemophlia B) Factor – X - Stuart-Prower factor 16 Factor XI - Plasma thromboplastin antecedent Factor XII - Hageman factor Factor XIII - Fibrin-stabilizing factor Note: There are 13 numerals but only 12 factors. Factor VI was subsequently found to be part of another factor. 17 Newer model of the coagulation pathway Coagulation pathways There are 2 pathways ◦- Extrinsic ◦- Intrinsic Extrinsic Pathway The extrinsic pathway of blood coagulation. Upon the introduction of cells, particularly crushed or injured tissue, blood coagulation is activated, and a fibrin clot is rapidly formed. The pathway of blood coagulation activated by tissue factor, a protein extrinsic to blood, is known as the extrinsic pathway. Basically, this pathway is responsible for imitating the coagulation process Coagulation test to measures this pathway is PT Intrinsic Pathway Intrinsic Pathway. The intrinsic pathway is activated by trauma inside the vascular system, and is activated by platelets, exposed endothelium, chemicals, or collagen. Coagulation tests to measured this pathway is PTT Common Pathway The common pathway of coagulation is the final stage in the coagulation cascade, where both the intrinsic and extrinsic pathways converge to form a stable fibrin clot. Here's an overview of the common pathway: Disseminated intravascular Coagulation (DIC) DIC is when your body’s blood clotting mechanism are activated throughout the body instead of being localized at an area of injury. Small blood clots form throughout the body and eventually the blood clotting factors are used up and are not available to form clots at the site of an actual injury. This results in either clotting symptoms or more often bleeding. 23 Symptoms of DIC Bleeding from multiple sites in the body Thrombosis formation indicated by a bluish color of the fingers Sudden bruising 24 Causes of DIC Bacterial or fungal infection of the blood Severe tissue injury( as in burns or head injury) Cancer Reactions to blood transfusion Obstetrical complications e.g. retained placenta after delivery 25 Tests used to detect DIC ( Basic DIC panel) PTT D- dimer Fibrinogen level PT All factors assays CBC . 26 Note: Patients that on anti coagulant therapy should have their PT or PTT checked regularly. This is to make sure that their medication is working properly
