bruise-contusion

patients with clotting problems can develop?

extensive bruising

unexplained bruising

life-threatening bleeding

clot formation (coagulation cascade) - steps

coagulation factors normally circulate in inactive form

1. after damage, blood vessel constricts to limit flow

2. platelet cells adhere and spread over injury site → forming a plug, primary haemostatic plug

3. coagulation cascade

4. coagulation factors produce thrombin to form fibrin clot

intrinsic vs extrinsic coagulation pathway

intrinsic

• activated from damaged vessel wall

• contact activated pathway

• coagulation factors are present and activated in bloodstream

extrinsic

• activated in response to injury of surrounding tissue

coagulation cascade steps of final common pathway

1. prothrombin → enzyme in inactive state

2. becomes thrombin → active enzyme

3. thrombin converts inactive protein fibrinogen

4. into fibrin → insoluble

5. forms cross-linked fibrin clot

blood thinners - examples

warfarin

aspirin

cortisone

function of blood thinners

interfere with the production of clotting factors in the cascade

cause increase fragility of capillaries resulting in

• reduced blood clotting ability

• severe bruising