secondary haemostasis

Question 1

what is secondary haemostasis failure?

Answer 1

failure of fibrin clot

Question 2

what causes secondary haemostasis to fail?

Answer 2

single clotting factor deficiency - usually hereditary (haemophilia)
multiple clotting factor deficiencies - usually acquired
increased fibrinolysis - usually part of complex coagulopathy
coagulation factor synthesis

Question 3

multiple clotting factor deficiencies causes

Answer 3

o usually acquired
o eg Disseminated Intravascular Coagulation
o liver failure
o vit K deficiency/ warfarin therapy
o Prolonged Prothrombin time (PT) and Activated partial thromboplastin time (APTT)

Question 4

coagulation factor synthesis issues

Answer 4

o All coagulation factors are synthesised in hepatocytes – Reduced in liver failure
o Factors II, VII, IX & X are carboxylated by vitamin K which is essential for function

Question 5

consequences of failure of fibrin clot formation

Answer 5

No characteristic clinical syndrome
May be combined primary/secondary haemostatic failure
Pattern of bleeding depends on
o	Single/multiple abnormalities
o	The clotting factors involved

Question 6

where does vitamin k come from?

Answer 6

•	Sources diet and intestinal synthesis 
•	Absorbed upper intestine 
•	Requires bile salts for absorption 
deficiency caused by 
•	Poor dietary intake
•	Malabsorption
•	Obstructive jaundice
•	Vitamin K antagonists (warfarin)
•	Haemorrhagic disease of the newborn