ABSITE Review - Hematology

Question 1

What are the three initial responses to vascular injury?

Answer 1

Vascular vasoconstriction, Platelet adhesion, Thrombin generation

Question 2

What is the convergence point betweem the intrinsic and extrinsic pathway?

Answer 2

Factor X

Question 3

Which coagulation factor helps with fibrin crosslinking?

Answer 3

Factor XIII

Question 4

What are the functions of thrombin?

Answer 4

Key to coagulation
Converts fibrinogen to fibrin and fibrin split products
Activates factors V and VIII
Activates platelets

Question 5

What are the functions of antithrombin III?

Answer 5

Key to anticoagulation
Binds and inhibits thrombin
Inhibits factors IX, X, XI
Heparin binds AT-III

Question 6

What are the functions of protein C?

Answer 6

Degrades factors V and VIII

Degrades fibrinogen

Question 7

What is the function of tissue plasminogen activator?

Answer 7

It is released from the endothelium and converts plasminogen to plasmin

Question 8

What is the function of plasmin?

Answer 8

Degrades factors V, VIII, fibrinogen and fibrin –> lose platelet plug

Question 9

What coagulation factor has the shortest half life?

Answer 9

Factor VII

Question 10

Which are the labile coagulation factors?

Answer 10

Factors V and VIII, activity is lost in stored blood but not in FFP

Question 11

Which is the only factor not synthesize in the liver?

Answer 11

Factor VIII which is synthesized in the endothelium

Question 12

Name the vitamin K-dependent factors.

Answer 12

II, VII, IX, X, protein C and protein S

Question 13

How long it takes to witamin K to take effect?

Answer 13

6 hours

Question 14

How long FFP lasts?

Answer 14

Effect is immediate and lasts 6 hours

Question 15

Describe the half-life of RBCs, PLTs, PMNs.

Answer 15

RBCs 120 days
PLTs 7 days
PMNs 1-2 days

Question 16

Where protacyclin is produce and what is its function?

Answer 16

Comes from endothelium.

Decreases platelet aggregation and promotes vasodilation.

Question 17

Where thromboxane is produce and what is its function?

Answer 17

Comes from platelets.
Increase platelets aggregation and promotes vasoconstriction.
Triggers release of calcium in platelets –> exposes GpIIB/IIIa receptor and causes PLT to PLT binding, PLT to collagen binding

Question 18

What coagulation factors are present in cryoprecipitate?

Answer 18

Contains the highest concentration of vWF VIII and fibrinogen

Question 19

What coagulation factors are present in FFP?

Answer 19

High levels of all factors, protein C, protein S and AT-III

Question 20

What cause release of VIII and vWF from endothelium?

Answer 20

DDAVP and conjugated estrogens

Question 21

What PT measures?

Answer 21

Measures II, V, VII and X; fibrinogen; best for liver synthetic function

Question 22

What PTT measures?

Answer 22

Measures most factors except VII and XIII; fibrinogen

Question 23

What is ACT and what arange is needed for anticoagulation?

Answer 23

Activated clotting time
ACT 150-200s for routine anticoagulation
ACT 460s for CABG

Question 24

What is the MC congenital bleeding disorder?

Answer 24

von Willebrand’s disease

Question 25

What is the function of vWF?

Answer 25

Links GpIb receptor on PLTs to collagen

Question 26

What are the diagnostic lab findings on vWF disease?

Answer 26

Normal PT Normal or abnormal PTT Long bleeding time (ristocetin test)

Question 27

What is the most common and/or severe type of vWF disease?

Answer 27

MC type - Type I (autosomal dominant) | Most severe type - Type III (autosomal recessive)

Question 28

Describe the genetics and diagnostic lab findings for Hemophilia A.

Answer 28

``` VIII deficiency Sex-linked recessive Need levels 100% preop and keep at 30% after surgery Dx - Prolonged PTT and normal PT Factor VIII crosses placenta ```

Question 29

Describe the genetics, diagnostic lab findings and treatment for Hemophilia B.

Answer 29

``` IX deficiency Sex-linked recessive Need levels 100% preop Dx - Prolonged PTT and normal PT Factor VIII crosses placenta Tx - recombinant factor IX concentrate or FFP ```

Question 30

Mention the diagnostic lab findings and treatment for Factor VII deficiency.

Answer 30

Dx - Prolonged PT, normal PTT, bleeding tendency | Tx - recombinant factor VII concentrate, FFP

Question 31

What medications can cause Acquired thrombocytopenia?

Answer 31

H2 blockers, heparin

Question 32

What is the defect in Glanzmann's thrombocytopenia and treatment?

Answer 32

GIIb/IIIa receptor deficiency on platelets | Tx - platelets

Question 33

What is the defect in Bernard Soulier thrombocytopenia and treatment?

Answer 33

GpIb receptor deficiency on platelets | Tx - platelets

Question 34

What is the MOA of Ticlopidine?

Answer 34

Decreases ADP in platelets, prevent exposure of GpIIb/IIIa

Question 35

What is the MOA of Dipirydamole?

Answer 35

Inhibits cAMP PDE, increases cAMP, decreases ADP-induced PLT aggregation

Question 36

What is the MOA of Pentoxifylline?

Answer 36

Inhibits PLT aggregation

Question 37

What is the MOA of Clopidogrel (Plavix)?

Answer 37

ADP receptor antagonist

Question 38

How ticlopidine, dipirydamole, pentoxyfylline and Plavix thrombocytopenia is treated?

Answer 38

PLTs

Question 39

Mention the cause of HIT.

Answer 39

AntiPLT antibodies (IgG PF4 antibody)

Question 40

What two MC findings in patients with HIT?

Answer 40

Thrombocytopenia (decrease of 50% PLTs or below 100) and thrombosis (white clot)

Question 41

What is the treatment for HIT?

Answer 41

Stop heparin | Give argatroban, hirudin, ancrod or dextran to anticoagulate

Question 42

What are the lab findings of DIC?

Answer 42

Decrease PLTs, prolonged PT, prolonged PTT, low fibrinogen, high fibrin split products, high D-dimer

Question 43

What is the MOA of ASA and how long before surgery it need to be stop?

Answer 43

Inhibits COX in PLTs | Stop 7 days prior to surgery, pts will have prolonged bleeding time

Question 44

What PLT level is adequate before and after surgery?

Answer 44

Keep > 50,000 before surgery and > 20,000 after surgery

Question 45

When urokinase is release and what is the MOA and treatment?

Answer 45

Can be release during prostate surgery and activates plasminogen causing thrombolysis Tx- aminocaproic acid

Question 46

What is the MC congenital hypercoagulability disorder? What is the defect and treatment?

Answer 46

Leiden factor - 30% spontaneous venous thromboses Resistance to activated protein C, defect on factor V Tx - heparin, warfarin

Question 47

What is the treatment for Hyperhomocysteinemia?

Answer 47

Folic acid and B12

Question 48

What is the treatment for AT-III deficiency?

Answer 48

Recombinant AT-III concentrate or FFP followed by heparin or hirudin or ancrod; warfarin

Question 49

What parameters are needed prior to surgery on a patient with polycythemia vera?

Answer 49

Keep Hct < 48 and PLTs < 400 before surgery

Question 50

Mention how to diagnose and treat Lupus anticoagulant.

Answer 50

Dx- prolonged PTT (but hypercoagulable and does not correct with FFP), positive Russell viper venom time, false-positive RPR test for syphilis Tx - heparin, warfarin

Question 51

Mention some causes of acquired hypercoagulability.

Answer 51

tobacco (MC), malignancy, infammatory states IBD, infections, OCP, pregnancy, RA, postop pts, myeloproliferative disorders

Question 52

What is the etiology of warfarin-induced skin necrosis?

Answer 52

Occurs when pt receives coumadin without being heparinized first. Protein C and S has a short half life and are the first to decrease compare with the procoagulatyion factors.

Question 53

What is the Virchow's triad?

Answer 53

Stasis, endothelial injury and hypercoagulability

Question 54

What is the treatment for 1st, 2nd and 3rd DVT or PE?

Answer 54

1st - warfarin for 6 months 2nd - warfarin for 1 year 3rd or significant PE - warfarin for lifetime

Question 55

Where is the MC place for DVT and why?

Answer 55

LLE due to compression of L common iliac vein by arterial system.

Question 56

What are the indications for a IVC filter?

Answer 56

1. Patients with contraindication to anticoagulation 2. Documented PE while on anticoagulation 3. Patients with free-flating iliofemoral, IVC or femoral DVT 4. Patients s/p pulmonary embolectomy

Question 57

Most PEs come from ____________ region.

Answer 57

Iliofemoral

Question 58

What is the MOA of warfarin?

Answer 58

Prevents vitamin K-dependent decarboxylation of glutamic residues

Question 59

What is the MOA of SCDs?

Answer 59

Improve venous return but also induce fibrinolysis with compression (release of tPA).

Question 60

What is the MOA of heparin? How can it can be reversed?

Answer 60

Activates AT-III | Reversed with protamine (1-1.5mg/100U heparin)

Question 61

What is the half-life of heparin? Where heparin is proccesed?

Answer 61

60-90 minutes | Cleared by Reticuloendothelial system

Question 62

What is the MOA of hirudin?

Answer 62

Irreversible direct thrombin inhibitor - the most potent

Question 63

What is the MOA of argatroban?

Answer 63

Direct thrombin inhibitor, half life 50 minutes

Question 64

What is the MOA of bivalirudin (Angiomax)?

Answer 64

Reversible direct thrombin inhibitor, half life 25-30 minutes

Question 65

What is the protamine reaction?

Answer 65

Hypotension, bradycardia and decreased heart function

Question 66

What is the MOA of aminocaproic acid?

Answer 66

Inhibits fibrinolysis by inhibiting plasmin

Question 67

What are the ABSOLUTE contraindications to thrombolytic use?

Answer 67

Active internal bleeding; recent CVA (<2 months); Intracranial pathology

Question 68

What are the MAJOR contraindications to thrombolytic use?

Answer 68

Recent (<10 days), organ biopsy, or obstetric delivery; L heart thrombus; active peptic ulcer or GI abnormality; recent trauma; uncontrolled HTN

Question 69

What are the MINOR contraindications to thrombolytic use?

Answer 69

Minor surgery; recent CPR; Afib w MV disease; bacterial endocarditis; hemostatic defects; diabetic hemorrhagic retinopathy; pregnancy