Coagulation Disorders Flashcards
Exam 4
Describe the brick and mortar explanation of thrombogenesis
Brick and mortar (thrombi) = mortar (fibrin) + bricks (platelet plugs)
What are the 4 phases of thrombogenesis?
- Adhesion
- Aggregation
- Secretion
- Cross-linking of adjacent platelets
What are the 2 parts to platelet adhesion?
- vWF binds to GP 1b receptor
- collagen binds to GP 1a receptor
What mediators are secreted during thrombogenesis?
5-HT, ADP, TXA2
Prostacyclin (PGI2) inhibits what?
clot formation/platelet aggregation
NSAIDs inhibit _____ and are (anti or pro) - _____ clot
PGI2, pro
Aspirin inhibits _____ and is (anti or pro) - _____ clot
TXA2, anti
________ holds the clots together
Fibrinogen
______ converts fibrinogen to fibrin
thrombin
____ converts prothrombin to thrombin
Xa
How is the extrinsic coagulation pathway initiated?
Tissue damage exposes tissue factor
How is the intrinsic coagulation pathway initiated?
Platelets interact with damaged endothelium
The ______ pathway describes the activation of thrombin, and formation of the fibrin clot
common
What are the 3 inhibitors in the coagulation pathway? What do they inhibit?
1) TFP1 - factor 7
2) Antithrombin - thrombin (factor 2a) and 10
3) Protein C (factors 5 and 8)
What are the 5 things that thrombin activates in the coagulation cascade?
factors 5, 8, 11, 13, and protein C
Describe the steps to the intrinsic coagulation pathway
1) damaged endothelium
2) activation of factor XII → XI →IX → X
3) Xa converts prothrombin → thrombin (common pathway)
Describe the steps to the extrinsic coagulation pathway
1) trauma activates factor VII and exposes tissue factor
2) tissue factor and VIIa → activates factor X
3) Xa converts prothrombin → thrombin (common pathway)
Describe the common pathway of coagulation
1) Xa converts prothrombin (II) → thrombin (IIa)
2) thrombin (IIa) converts fibrinogen (I) to fibrin (Ia)
3) XIIIa (activated by thrombin) converts fibrin (Ia) → cross-linked fibrin clot
How is protein C activated?
Thrombin activates inactive protein C + thrombomodulin and protein S converts it into active protein C
What is Virchow’s triad?
1) stasis (decreased blood flow)
2) endothelial injury (damage to inside of blood vessel)
3) hypercoagulability
Virchow’s triad can result in _____
Deep Vein Thrombosis (DVT)
What are the 2 types of DVT risk factors?
Inherited and acquired
What are the 5 types of inherited DVT risk factors?
- Antithrombin III deficiency
- Protein C deficiency
- Protein S deficiency
- Sickle cell anemia
- Activated protein C resistance
What are the 5 types of acquired DVT risk factors?
- Bedridden
- Surgery/trauma
- Obesity
- Estrogen use
- Malignancies
- Chronic venous insufficiency
____ is the over stimulation of the blood clotting mechanism
DIC - Disseminated coagulation
Differentiate between red and white thrombi
White - high pressure arteries; platelets + thrombin
Red - low pressure vein, long tail, red cells around white thrombus
What are the 3 results of DIC?
- Generalized blood coagulation
- Excessive consumption of factors and platelets
- Leads to spontaneous bleeding
What are the 4 causes of DIC?
- Massive tissue injury
- Malignancy
- Bacterial sepsis
- Abruptio placentae