CS - Bleeding Flashcards
3 responses of injury to blood vessel
- vasoconstriction
- collagen exposure
- tissue factor
What does tissue factor do?
initiates extrinsic pathway
What initiates intrinsic pathway?
collagen exposure
What does collagen exposure lead to?
- PLT activation
- intrinsic pathway
What is needed for platelet plug?
- platelet activation leading to platelet adhesion and aggregation
- vasoconstriction
What is the final common pathway?
- result of intrinsic and extrinsic pathways
- culminates in thrombin conversion to fibrin to fibrin clot with PLT plug
How can extrinsic pathway be measured?
PT
How can the intrinsic pathway be measured?
PTT
What causes thrombin inactivation? 3
- antithrombin
- tissue factor pathway inhibitor
- activated C-protein S
Signs - hypovolaemic shock/ hypoperfusion
- slow CRT
- white MM
- Tx : shock bolus of isotonic crystalloid
What does a weak peripheral pulse suggest?
hypovolaemia (anaemia causes bounding pulse)
What aspects of CBC suggest an anaemia is regenerative?
- increased MCV
- decreased MCHC
- increased reticulocytes
- increased RDW
- confirmed by polychromasia on blood smear
What can suggest a peripheral cause for thrombocytopaenia?
megakaryocytes (e.g. destruction, consumption)
What are the types of thrombocytopaenia?
- PRIMARY: reduced platelets, clotting factors normal
- SECONDARY: reduced clotting factors, platelets normal
Types of Immune- Mediated Thrombocytopaenia (IMTP)
- PRIMARY/ IDIOPATHIC: commonly diagnosed as no other cause can be identified
- SECONDARY: if other causes of the TP can be found, e.g. parasites, neoplasia, infection, drug hx