Coagulation problems Flashcards
What are the two kinds of fibrin clot formation failures?
single and multiple clotting factor deficiencies
What are examples of multiple clotting factor deficiencies?
liver failure
vit K deficiency
warfarin
DIC
What happens to the PT and APTT in multiple clotting factor deficiencies?
prolonged
How does liver failure cause fibrin clot formation failure?
hepatocytes synthesise each clotting factor - when hepatocytes are damaged they can no longer do that
How does Vitamin K deficiency cause fibrin clot formation failure?
factor 2,7,9,10 are carboxylated by vitamin K
What are the properties of vitamin K?
found in leafy greens
requires bile salts for absorption
absorbed in the upper intestine
What causes vitamin K deficiencies?
vit K antagonists - warfarin
obstructive jaundice
malabsorption and poor dietry intake
haemorrhagic disease of the newborn - babys have littel vit K so get vit K IM at birth
What causes DIC?
due to trauma - tissue factor is released from damaged tissues and causes excessive activation of homeostatic circulation system affecting primary and secondary haemostasis and fibrinolysis
may lead to end organ failure if microvascular thrombus formation
What is a single clotting factor deficiency?
Haemophillia
What is haemophilia?
X linked hereditory disorder - males affected, females carriers
What clotting factor is affected in haemophilia A?
Factor VIII
What clotting factor is affected in haemophilia B?
Factor IX
How does haemophillia present?
bleeding into ankle and knee joints - irritates the synovium which forms new vessels which burst and bleed
What vessels are affected in haemophillia?
medium -> large
What are severe features of haemophilia?
recurrent haemarthroses and soft tissue bleeds
prolonged bleeding after minor surgery
