normal haemostasis
Last reviewed 01/2018
When a blood vessel is damaged, three processes are important in stopping haemorrhage:
- vascular spasm in response to injury
- platelet plug formation on the damaged endothelial surface
- activation of the coagulation cascade
Defects with respect to any of these processes cause delayed cessation of bleeding. The type of disorder influences the pattern of bleeding.
If there are vascular or platelet defects then this results in bleeding from small vessels which manifests as cutaneous and mucosal bleeding e.g. epistaxis or GI haemorrhage.
In contrast, coagulation disorders characteristically cause bleeding into deeper tissues e.g. subcutaneous or intramuscular haematomata or joint bleeds (haemarthroses).