Secondary Hemostasis

Question 1

Intrinsic and Extrinsic Pathways

Answer 1

Intrinsic: XII, XI, IX, VIII, to X

Extrinsic VII to X

Question 2

PT and PTT (pathways and drug)

Answer 2

PT: Extrinsic, monitor for Warfarin
PTT: Intrinsic, monitor for heparin

Question 3

Hemophilias A, B, and C (factor deficiency, inheritance, lab measurement, treatment)

Answer 3

All increased PTT
A: VIII, XLR
B: IX, XLR
C: XI: AR
Treatment: Desmopressin + whatever factor missing

Question 4

von Willebrand Disease (what it is, inheritance, labs, dx, treatment)

Answer 4

Defect in vWF so get defect in platelet plug (decreased adhesion) and intrinsic pathway (can’t stabilize factor VIII), so increase in BT and PTT but normal PT and platelet count
Dx: Ristocetin test, ristocetin cofactor causes vWF-GpIB binding so won’t agglutinate
Treat with desmopressin which releases vWF from endothelium

Question 5

DIC (what it is/a lotta important labs, 8 causes)

Answer 5

Widespread activation of clotting so deficiency in everything causing bleeding state. Decreased PC, increased BT/PTT/PT. Schistocytes, increase D-dimers (fibrin split products), decreased fibrinogen because used up, decreased factors V and VIII
STOP Making New Thrombi
Sepsis (G-s), Trauma, Obstetric complications, acute Pancreatitis, Malignancy, Nephrotic syndrome (maybe), Transfusion
Also Rattlesnake venom causes widespread coag