haemostasis and bleeding

Question 1

clot formation vs clot dissolution

Answer 1

formation : platelets endothelium, VWf

coagulation cascade

dissolution :fibrinolysis antithrombins, protein C/S

tissue factor pathway inhibitor (TFPI)

Question 2

haemostasis steps

Answer 2

1) vasoconstriciton
2) platelet aggregation primary haemostatic plug
3) coagulation cacade

Question 3

endothelium function in haemostasis

Answer 3

synthesis of PGI2 (inhibits platelets)

vWF (aids adhesion of platlets)

plasminogen activators (fibrinolysis)

thrombomodulin (anticoagulant)

maintains barrier between blood and procoagulant subendothelial structures

Question 4

platelet lifespan and implication

Answer 4

platelets last 10 days, therefore if aspirin is stopped wont see effects for 7-10 days (surgical assessment)

Question 5

presentation of VWD

presentation of VWD

Answer 5

as if they do not have platlets as VWF facilitates adhesion , increase bleeding

Question 6

which pathway is aptt pt

Answer 6

intrinsic pathway aptt

extrinsic pt

Question 7

factor v leiden

Answer 7

failure of degredation of factor5 by activated protein C, hypercoagulation by increased clotting cascade thrombin activation, DVT, PE stroke etc

most common hereidtary in caucasians

Question 8

intrinsic pathway order

Answer 8

12 11 9 (8) –> 10 (5) 7