Secondary Haemostasis Issues Flashcards
What is DIC?
Excessive/inappropriate activation of the haemostatic system
Give examples of when DIC occurs
Major trauma ABO incompatibility reactions Cancers Septic shock Ischaemia
Describe the pathogenesis of DIC
TF released from damaged tissue Activates coag cascade Multiple thrombus formation Causes ischaemia More TF release cycle continues
How does DIC present?
Shock
Bleeding from mouth, nose and venopuncture sites
Ecchymoses
Evidence on thrombosis
What does coag screen show in DIC?
PT, APTT, TT all prolonged
What does FBC show in DIC?
Thrombocytopenia
d-Dimer is high in DIC
true/false
True
How is DIC treated?
Replace what is lost: Platelets or FFP and fibrinogen
Consider heparin if critically ill and not bleeding
What is vitamin K needed for?
Gamma-carboxylation of glutamic acid residues on factors II, VII, IX, X on proteins C and S
Why do caog factors need carboxylated to work?
Adds negative COOH group so that positive Ca2+ sticks to the coag factor
Platelets stick to this
What is vitamin K?
Fat soluble vitamin
What does vitamin K need to be absorbed?
Bile salts
How does vitamin K def present?
GI bleed
Cerebral bleed
Bruising
Haematuria
What may lead to inadequate stores of vit K?
Abx Bleeding disorders (haemorrhagic disease of the newborn)
What may leads to malabsorption of vit K?
Obstructive jaundice
Crohns
Which drugs may cause def of Vit K?
Abx
OAC
What does coag screen show in vit K def?
PT and APTT prolongation
What is the management of vit K?
IV vit K1
phytomenadione
How may cholestasis lead to vit K def?
Lack of bile salts causing malabsorption of vit K
How is haemophilia inherited?
X linked
Which factor is defective in haemophilia A?
VIII
Which factor is affected in haemophilia B?
IX
What are “target joints”?
Mostly ankle or knee Movement leads to bleed Fibrin cant be made to stop bleed Iron causes joint irritation Neovascularisation occurs - but these are fragile and break Cycle continues
<1 IU/dL of factor VIII indicates…
Severe haemophilia
1-5 IU/dL of factor VIII indicates…
Moderate haemophilia
> 5 IU/dL of factor VIII indicates…
Mild haemophilia
Describe bleeding in moderate haemophilia
Prolonged bleed following injury
Describe bleeding severe haemophilia
Target joints
Bleed spontaneously
Describe bleeding mild haemophilia
Prolonged bleeding after surgery
Describe coag screen in haemophilia A
Normal PT
Prolonged APTT
How is mild haemophilia A treated?
Vasopressin IV/subcut
Or factor VIII IV every 2 days
How is haemophilia B treated?
Factor IX given every 2 weeks
What is the goal of drug therapy in haemophilia?
To keep factor levels above 2%
