Disorders Of Hemostasis Flashcards
(22 cards)
What is the clinical presentation for disorders of primary hemostasis (4)?
(1) Mucocuteneous Bleeding
(2) Easy Bruising
(3) Heavy Menstrual Bleeding
(4) Petichiae
How do patients present with disorders of secondary hemostasis (3)?
(1) Hemarthrosis
(2) Intramuscular Bleeding
(3) Retroperitoneal Bleeding
What are the factors of the extrinsic pathway of secondary hemostasis?
Factor VII
Tissue Factor
What are the factors of the intrinsic pathway of secondary hemostasis?
Factors XII, XI, IX, VIII
What are the components of the common pathway of secondary hemostasis?
Factors II (Prothrombin), V, X Fibrinogen (Factor I)
Which factors does warfarin affect?
II, VII, IX, X
How do you evaluate an elevated INR (PT)?
50:50 mixing study:
(A) INR/PT corrects = Factor Deficiency (Ddx includes FVII deficiency, vitamin K deficiency, liver disease).
(B) INR/PT does NOT correct: inhibitor present (ddx includes lupus anticoagulant, possible FVII inhibitor)
How do you evaluate an elevated aPTT?
50:50 mixing study interpretation:
(1) aPTT corrects = factor deficiency
(2) aPTT does not correct = inhibitor present
How would you investigate a patient with an elevated aPTT & PT?
50:50 Mixing Study Interpretation:
(A) Corrects = Factor Deficiency (Measure FII, V, X) -> if factor low, deficiency confirmed
(B) Does NOT correct = Inhibitor (rule out lupus anticoagulant, measure FII, V, X and then the inhibitor for the factor that is low)
What would you send to investigate for Von Willebrand disease (3)?
VWF Ag (Quantity) Ristocetin Cofactor (VWF activity) Factor VIII Level
aPTT can be normal and IS NOT a good screening test
What are the components of cryoprecipitate?
Factor I (Fibrinogen) Factor VIII Factor XIII Von Willebrand Factor Fibronectin
What are the different types of Von Willebrand disease?
Type I: Quantitative Deficiency
Type II: Qualitative Deficiency
Type III: No VWF produced (behaves like Hemophilia A)
How would you manage a women with VWD and heavy menstrual bleeding?
ASH guidelines recommend OCP and TXA over desmopressin use.
How would you manage a patient who has Von Willebrand Disease who presents to hospital with minor bleeding or requires a minor surgical procedure?
Type I: DDAVP (not in most Type II or III), +/- concentrates of VWF and FVIII
Type I or III: Will require cryopreciptate or concentrates of VWF and FVIII (Humate P)
What is the target FIII and VWF activity level after surgery?
Target for both is > or = 0.5 IU/mL for at least 3 days post-op.
What is the definition of ITP?
Platelets < 100 with an absence of other causes.
When would you treat a patient with ITP?
(1) Not bleeding & platelets < 30:
A. First-Line: Steroids (Pred or Dex), IVIG, anti-D
B. Second-Line: Splenectomy, Rituximab, TPO-R agonists
(2) Active Bleeding
A. Steroids + TXA + IVIg
B. Life threatening - Plt transfusion +/- splenectomy
When/how would you treat ITP in pregnancy?
(1) Bleeding
(2) Delivery
(3) Platelets < 50 + GA > or = 36 weeks
Prednisone (not dex - crosses the placenta)
IVIg
Target platelets > 50 for delivery & > 80 for neuraxial anasthesia
When would you admit a newly diagnosed ITP patient?
If their platelets are < 20
How do you interpret the results of the 4T score for heparin induced thrombocytopenia?
(1) Score < or = 3: Low probability (Rules out HIT)
Stop heparin, start alternate anticoagulation and send heparin immunoassay if:
(2) Score 4-5: Intermediate probability
(3) Score 6-8: High probability
How would you manage suspected HIT?
(1) Alternative Anticoagulant (argatroban, danaparoid)
(2) Bilateral Leg Dopplers
(3) If HIT confirmed, start warfarin when platelets > 150, target INR 2-3 and continue for 1 month if no thrombosis, or 3 months if thrombosis is present.
How do you rule out thrombocytopenia?
Repeat CBC with platelets count in a citrate tube (blue top) rather than an EDTA tube.
