This is a draft cheat sheet. It is a work in progress and is not finished yet.
Normal Hemostasis
Sequence of response |
1. Vasoconstriction |
2.Formation of platelet plug (Primary hemostasis) |
3. Blood clot formation (Secondary) |
4. Clot stabilization and resorption |
Primary hemostasis
1. Platelet adhesion and shape change |
- Stick to rough surface thru vWF |
2.Shape change of platelet |
- Spiky |
- Alter surface glycoproteins for fibrinogen affinity |
- Translocate -vely charged phospholipids to surface |
- Provide site for coagulation factor complex assembly |
3.Platelet release reaction |
- TXA2, ADP, Serotonin |
- Recruit platelets |
4. Platelet aggregation |
- Form platelet plug |
- TXA2, ADP, Thrombin, Fibrinogen |
Hemorrhage
Petechia<Purpura<Ecchymosis |
Hemorrhagic disorders |
- Defects in coagulation factors, platelets or vessel walls |
1. Defects of primary hemostasis (Platelets/ vWF) |
2. Defects of secondary hemostasis (Coagulation factors) |
3. Vascular fragility |
Emobolism
- Detached intravascular solid, liquid or gaseous mass that is carried by blood away form its origin |
- Composed of thrombi |
- Cause infarction (99%) |
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Secondary Hemostasis (Blood clot formation)
Clotting factors |
Intrinsic pathway |
1. Plasma Proteins |
- By negatively charged surface |
2. Tissue factor |
- Initiate XII |
3. Calcium |
Common stages of Clotting |
Extrinsic pathway |
1. Factor X -> Xa |
- By tissue factor |
2. Prothrombin (II) -> Thrombin (IIa) |
- Initiate VII |
3. Fibrinogen (I) -> Fibrin (Ia) |
- Fibrin trap neutrophil & RBC |
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Lab test for clot formation |
Prothrombin time: Extrinsic |
Partial thromboplastin time: Intrinsic |
Retraction: Platelet adhering to fibrin contract, squeeze out serum |
Clot Stabilization and resorption
- Fibrinolysis: Plasminogen -> Plasmin (Clot buster) |
- Or by plasminogen activators (t-PA) |
Thrombin
1. Convert fibrinogen to cross-linked fibrin |
2. Platelet activation |
3. Pro-inflammatory |
4. Anticoagulant |
Thrombosis
1. Endothelial injury |
- Thrombosis in heart/ arterial circulation |
2. Stasis/ turbulent blood flow |
- Disrupt laminar flow & bring platelet to endothelium |
3. Hypercoagulability of blood |
- aka Thrombophillia |
Fate of thrombus |
1. Propagation |
2. Embolization |
3 Dissolution |
4. Organization& Recalalization |
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