Disorders of blood coagulation Flashcards
1
Q
What is clotting?
A
- Tightly regulated process that stops bleeding at site of injury
- Keeps blood in and pathogens out
- Must remain localised
- Blood loss is stopped by formation of a plug composed of platelets and fibrin
2
Q
What is the mechanism of clotting?
A
3
Q
What is the primary haemostasis pathway?
A
- Endothelium releases von Willebrand factor which circulates in the blood
- If collagen becomes exposed to blood (because endothelium is damaged), von Willebrand factor binds to it
- Platelets express receptors for both collagen and von Willebrand Factor and become activated when these proteins bind to them
- Activated platelets expression fibringoen receptors required for aggregation
4
Q
What is the secondary haemostasis pathway?
A
- Tissue factor activates the coagulation cascade to initate a minor burst of thrombin
- Factor FV11a binds to tissue factor –> conversion of prothrombin to thrombin
- Thrombin activates receptors on platelets and endothelium amplifying platelet aggregation and initating store of von Willebrand factor
5
Q
What is fibrinolysis?
A
= breaking down fibrin (AKA thrombolysis)
- Plasminogen is activated to plasmin by t-PA
- Plamsin degrades the fibrin mesh to fibrin degradation products which can be cleared
6
Q
What are anticoagulants?
A
- regulate how much thrombin is activated
7
Q
What is haemophilia?
A
Failure to clot leading to haemorrhage
- Mutations in coagulation factors (haemophilia A and B) - bleeding into joints
- Platelet disorders (von Willebrand disease) - affects mucous membranes
- Collagen abnormalities (fragile blood vessels)
8
Q
What is thrombophilia?
A
= excessive clotting leading to thrombosis
Mutations in coagulation factors
Malignancy increasing clotting factors
3 ways:
9
Q
What is Disseminated intravascular coagulation (DIC)?
A
= whole body clots
- Infection - occurs in sepsis
- Depletion of clotting factors and platelets leads to bleeding
10
Q
What is deep vein thrombosis?
A
11
Q
How can you manage thrombosis?
A
