What are the three stages in a vessel that arrest haemorrhage?
1. Contraction of vessel wall, vascular response
2. Platelet aggregation - unstable clot
3. Initiation of clotting cascade - stable fibrin clot
Haemorrhagic disease can be divided into 2 situations:
1. Where bleeding is profuse at the site of operation. Therefore PROLONGED bleeding, but clotting may be normal.
2. Where bleeding stops for a short time after op, but persistent haemorrhage occurs later owing to failure of the blood to clot. Therefore bleeding time may be normal, but there is an abnormality in coagulation.
Local causes of haemorrhage (3):
Local vascular lesion (eg. haemangioma)
Why does trauma cause Haemorrhage?
Excessive trauma causes ST bleeding and may also damage blood vessels.
Why does infection cause Haemorrhage?
Bacteria can break down the clot.
Loose pieces of bone or retained tooth fragments also favour secondary infection.
Systemic causes of haemorrhage (3)?
1. Platelet disorders
2. Vessel disorders
3. Coagulation disorders
Generally what sort of symptoms would you see from platelet disorders
Bruising of skin
Bleeding from mucosal membranes
Generally what sort of symptoms would you see from coagulation disorders?