Haematology II Flashcards
Thrombocytopaenia
Decreased production: Marrow aplasia, uraemia, alcohol)
Decreased Survival: ITP, drugs
Increased consumption: DIC, heparin
Vitamin K important for
Gamma carboxylase of II, VII, IX and X and protein c and s
Thrombophilia screen
Factor V Leiden
Antithrombin III
Protein C
Protein S
Factor V Leiden
Resists deactivation by Protein C
Antithrombin III deficiency
Usually deactivates VII, IX, X, XI, kallikrein and plasmin
Protein C and S
AD
Thrombin activates protein C (protein S is cofactor) by binding to thrombomodulin. Protein C reduces fibrin production by by degrading FVa and VIIIa
DIC
Underlying condition (malignancy, trauma, infection)
Haemostasis activation
microvascular thrombosis causing tissue ischaemia, RBC haemolysis and fibrinolysis.
The haemolysis activation and the above then cause depletion of coagulation factors causing bleeding.
Prolonged APTT, PT and TT, thrombocytopenia, bleeding, increased FDP and reduced fibrinogen
Management of DIC
fluid resuscitateion
Underlying condition
FFP, cryoprecipitate, platelet concentrate
Virchows triad
Endothelial damage
Venous stasis
Hypercoagulation
Well’s criteria
- Entire leg swelling
- Calf swelling >3cm c.f other
- Localised calf tenderness
- Pitting oedema
- Collateral superficial veins
- Recent bedridden >3days or surgery in last month
- Paralysis/paresis/POP of lower limb
- Active cancer (within 6 months)
Alternative diagnosis (-2)
> 3 high >2 moderate <1 Low
Differentials of DVT
Lymphoedema
Ruptured Baker’s cyst
Cellulitis
Anticoagulation drugs
Aspirin: Inhibits COX
Dipyridamole and clopidogrel (stop 2 weeks before surgery)
Heparin (inactivated antithrombin III) neutralised by protamine-parenteral or subcut
Stop subcut heparin 24hours before surgery
Iv heparin more profound effect but only 6hrs before surgery
