Hemostasis And Thrombosis

Front 1

What are the steps to hemostasis? (3)

Back 1

1. Primary hemostasis: adhesion, activation, aggregation
2. Secondary Hemostasis: Intrinsic+Extrinsic pathways->Common Pathway->Active Thombin->Fibrin Clot Formation
3. Resolution: clot buster activation of plasminogen->fibrinolysis

Front 2

Secondary Hemostasis: Extrinsic Pathway Steps, Intrinsic Pathway Steps, Common Pathway Steps, Extrinsic Pathway Test, Intrinsic Pathway Tests

Back 2

1. Extrinsic Pathway Steps: VII->VIIa(TF), X->Xa (TF/VIIa), common pathway
2. Intrinsic Pathway Steps: XII->XIIa, XI->XIa(XIIa), IX->IXa(XIa), X->Xa(IXa+Ca+VIIIa+phospholipid), Common Pathway
3. Common Pathway Steps: Prothrombin/II->Thrombin/IIa(Ca+Va+Xa+pospholipid)
4.Extrinsic Pathway Test: INR (standardized PT)
5. Intrinsic Pathway Test: PTT

Front 3

What does Thrombin do?(5)

Back 3

1. Fibrinogen to Fibrin
2. Activation of plateletts
3. Activation of V and VIII
4. Activation of XIII
5. Activation of protein C

Front 4

What does Plasmin degrade? (3)

Back 4

1. Fibrin
2. Fibrinogen
3. Clotting Factors

Front 5

How do you test for a bleeding disorder? (3)

Back 5

1. Bleeding History: primary hemostasis (excessive/prolonged, immediate, superfical bleeds) vs. secondary hemostasis problem (Normal/slightly prolonged, delayed, deep bleeds)
2. Primary Hemostasis Tests: vWF function (PTT, vWF antigen, vWF ristocetin cofactor, FVIII level), platelet count (CBC), platelet function (specialized tests)
3. Secondary Hemostasis Tests: PT/INR (Extrinsic: FVII,X,V,prothrombin,fibrinogen), PTT (Intrinsic: XII,XI,IX,VIII,X,V,prothrombin,fibrinogen)

Front 6

What is the approach to dealing with abnormal PT or PTT on screen?

Back 6

Repeat test with 1:1 mix of patient:normal plasma
If normal means there is truly a factor deficiency and you should check individual factors
If abnormal means there are inhibitors which are invalidating the test

Front 7

What are less commonly used tests for secondary hemostasis? (4)

Back 7

1. Individual Factor Levels
2. Fibrinogen Level
3. Thrombin Clotting Time
4. Inhibitors: specific, non-specific