Hemostasis/Coagulopathies/Hypercoag

Question 1

where are most coag factors synthesized? exceptions?

Answer 1

liver

exceptions: VIII (liver and vascular endothelium), vWF ( megakaryocytes and endothelial cells)

Question 2

prothrombinase complex

Answer 2

factor Va and factor Xa on platelet phospholipid

Question 3

thrombin burst

Answer 3

thrombin feeds back to activate XI to XIa –> more thrombin

Question 4

D-dimer

Answer 4

fibrinolytic breakdown of cross-linked fibrin –> clot formation and breakdown
- elevated in acute thrombosis

Question 5

Bernard Soulier disease

Answer 5

defect in GPIb receptor

Question 6

Glanzmann thrombasthenia

Answer 6

defecet in GPIIb/IIIa receptor

Question 7

vWF function

Answer 7

tethers platelets to sub endothelium at site of injury

chaperones factor VIII

Question 8

vWF types

Answer 8

1 - most common, low levels of vWF
2 - normal levels but messed up function
3 - absent vWF
acquired - autoantibodies

Question 9

vWF disease tx

Answer 9

DDAVP (desmopressin) - stimulates vWF and VIII release -

vWF replacement

Question 10

how to distinguish vitamin K deficiency from liver failure (labs)?

Answer 10

factor V normal in vit K deficiency

Question 11

explain why liver disease can cause both bleeding and clotting

Answer 11

bleeding: coag factors made in liver made in liver
clotting: anticoag factors made by liver, activated coag factors cleared by the liver

Question 12

3 causes of acquired thrombophilia

Answer 12

1. hematologic disorders (myeloproliferative, PNH)
2. heparin induced thrombocytopenia
3. hyperhomocysteinemia

Question 13

activated protein C resistance

Answer 13

mutation in factor V (factor V leiden)

mild risk factor for venous thromboembolism

Question 14

Prothrombin 20210A

Answer 14

excessive production of prothrombin

mild risk factor for venous thromboembolism

Question 15

Hereditary protein C deficiency

Answer 15

autosomal dominant
7x risk of venous thromboembolism
normally works w/ cofactor S to inactivate V and VIII

Question 16

hereditary antithrombin deficiency

Answer 16

autosomal dom

decreases protective effect of heparin-like molecules produced by endothelium –> risk for thrombus