Fiser: Hematology Flashcards

1
Q

what are three main functions of thrombin?

A
  1. converts fibrinogen to fibrin
  2. activates factor V and VIII
  3. Activates platelets
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2
Q

what are three factors that are involved in normal anticoagulation?

A

antithrombin III, protein C and protein S

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3
Q

what are the only two factors not synthesized in the liver?

A

factor VIII and vWF (made in the endothelium)

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4
Q

function of protein C

A

degrades factors V and VIII and fibrinogen

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5
Q

function of protein S

A

cofactor of protein C

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6
Q

what are the vitamin K dependent factors?

A

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

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7
Q

whats the normal half life of PRBCs and platelets?

A

PRBCs = 120 days, Plat = 7 days

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8
Q

functions of prostacyclin? where does it come from?

A
  1. decreases platelet aggregation and promotes vasodilation
  2. increases cAMP in platelets
    * antagonist to TXA2, comes from endothelium
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9
Q

functions of Thromboxane? where does it come from?

A
  1. increases platelet aggregation and promotes vasoconstriction
  2. triggers release of calcium in platelets to cause platelet-platelet binding and platelet-collagen binding
    * from platelets
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10
Q

what is cryoprecipitate?

A

contains highest concentration of vWF-VIII, has high levels fibrinogen, used in von willebrands disease and hemophilia A (factor VIII deficiency)

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11
Q

what does ddavp do?

A

causes the release of VIII and vWF

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12
Q

what is the best measurement for liver synthetic function?

A

PT (prothrombin time)

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13
Q

what does PT (prothrombin time) measure?

A

II, V, VII, and X, fibrinogen, (best for liver synthetic function)

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14
Q

what does the PTT measure? ( partial thromboplastin tme)

A

measures most factors EXCEPT VII and XIII so does not pick up factor VII deficiency!

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15
Q

what is the most common congenital bleeding disorder?

A

von Willbrand’s disease

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16
Q

what are the different types and inheritance patterns of von willebrand’s disease?

A

type I: AD, MC, reduced quantity of vWF, mild symptoms
type II:AD, defect in vWF molecule itself, vWF doesnt wok well
type III:AR, most severe bleeding but rare, complete vWF deficiency (DDAVP does not work here!- give cryo)

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17
Q

what is the function of vonwillbrands factor?

A

link Gp1b receptor on platelets to collagen

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18
Q

what do you see on coag profile in vW disease?

A

PT normal, PTT can be normal or abnormal, bleeding time is long (ristocetin test)

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19
Q

what is hemophilia A and inheritance?

A

factor VIII deficiency, sex linked recessive

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20
Q

what coag profile do you see in hemophilia A?

A

prolonged PTT, normal PT (factor VIII deficiency)

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21
Q

tx of hemophilia A bleeding? (hemarthrosis, epistaxis, ICH)

A

factor VIII concentrate or cryoprecipitate)

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22
Q

What is hemophilia B? inheritance?

A

factor IX deficiency, sex linked (aka christmas disease)

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23
Q

what coag profile do you see in hemophilia B?

A

prolonged PTT, normal PT (factor IX deficiency)

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24
Q

tx for hemophilia B bleeding?

A

FFP or recombinant factor IX

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25
Q

what are the key functions of antithrombin III?

A

binds and inhibits thrombin

inhibits factors IX, X and XI

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26
Q

what is the MOA of heparin?

A

activates antithrombin III up to 1000x the normal activity, neutralizes factors Xa and IIa

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27
Q

coag profile of factor VII deficiency?

A

prolonged PT and normal PTT

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28
Q

what is Glanzmann’s thrombocytopenia?

A

GIIb/IIIa receptor deficiency, thus platelets cant bind to eachother, tx = platelets

29
Q

what is benard soulier disease?

A

Gp1b receptor deficiency on platelets, thus cannot bind to collagen, tx = platelets

30
Q

how does uremia inhibit platelet function?

A

seen in BUN >60-80, inhibits release of vWF

31
Q

1st line treatment for uremia

A

hemodialysis (then DDAVP for acute reversal, cryo for mod to severe bleeding)

32
Q

cause of heparin induced thrombocytopenia?

A

anti-heparin antibodies (IgG heparin-PF4 antibody)

33
Q

what do you give to someone w HIT for anticoagulation instead?

A

argatroban (direct thrombin inhibitor)

34
Q

what is MOA of Plavix?

A

clopidogrel: ADP receptor antagonist

35
Q

what is most common congenital hypercoagulability disorder?

A

factor V leiden

36
Q

what is factor V leiden? tx?

A

defect on factor V that causes resistance to activated protein C
tx: heparin or coumadin

37
Q

in what subgroup does heparin NOT work?

A

patients w antithrombin III deficiency

38
Q

what is anti-phospholipid antibody syndrome?

A

caused by antibodies to phospholipids including cardiolipid and lupus anticoagulant leading to prolonged PTT but are hypercoagulable

39
Q

how do you diagnose anti-phospholipid antibody syndome?

A

prolonged PTT and positive Russell viper venom time (false positive RPR test for syphilis)

40
Q

what is the most common factor causing acquired hypercoagulability?

A

tobacco

41
Q

pathophysiology of warfarin induced skin necrosis?

A

due to short half life of protein C and S, theyre first to decrease compared to procoagulation factors which results in hyperthrombotic state (pts w relative protein C deficiency are esp susceptible)

42
Q

what is virchows triad?

A

stasis, endothelial injury, hypercoagulability

43
Q

MOA and uses: Aminocaproic acid (Amicar)

A

inhibits fibrinolysis by inhibiting plasmin, procoagulant, used in DIC or persistent bleeding from thrombolytic overdose

44
Q

MOA warfarin

A

prevents vitamin K dependent decarboxylation of glutamic residues on vitamin K-dependent factors

45
Q

MOA apixaban (eliquis)

A

direct thrombin inhibitor

46
Q

what are the 3 direct thrombin inhibitors?

A

dabigatran (pradaxa), apixaban (eliquis), rivaroxaban (xarelto)

47
Q

MOA protamine

A

reverses heparin by binding to it

48
Q

what is half life of heparin?

A

60-90 minutes

49
Q

which anticoagulation agent can be used in pregnancy?

A

heparin does not cross placenta (warfarin does)

50
Q

what is a potential side effect of protaime?

A

it cross reacts w NPH insulin or previous protamine exposure, 1% get protamine reaction (hypotension, bradycardia, decreased heart function)

51
Q

MOA enoxaparin

A

LMWheparin, binds and activates antithrombin III but neutralizes only factor Xa (heparin neutralizes Xa and IIa)

52
Q

MOA argatroban

A

reversible direct thrombin inhibitor, use in pts w HITT

53
Q

MOA streptokinase

A

thrombolytic- activates plasminogen, follow fibrinogen levels

54
Q

MOA urokinase

A

thrombolytic- activates plasminogen, follow fibrinogen levels

55
Q

MOA tPA

A

thrombolytic- activates plasminogen, follow fibrinogen levels

56
Q

what is ancrod?

A

malayan pit viper venom, stimulates tPA release

57
Q

what is Hirudin?

A

Hirulog from leeches, irreversible direct thrombin inhibitor, the most potent direct inhibitor of thrombin, high risk of bleeding complications

58
Q

what type of hypersensitivity reaction is ABO incapatability?

A

type II (antibody mediated)

59
Q

what is the most common transfusion reaction?

A

febrile nonhemolytic transfusion reaction

60
Q

what is febrile nonhemolytic transfusion reaction?

A

MC transfusion rxn, recipient antibody reaction against donor WBCs (cytokine release)

61
Q

pathophysiology of transfusion related urticaria?

A

recipient antibodies against donor plasma proteins (eg peanuts) or IgA in an IgA deficient patient

62
Q

pathophysiology of transfusion related anaphylaxis?

A

recipient antibodies against donor IgA in an IgA deficient recipient

63
Q

what is TRALI?

A

transfusion related acute lung injury: rare
caused by DONOR antibodies to recipient WBCs, clot in the pulmonary capillaries leading to pulmonary edema <6hours (ARDS)

64
Q

MCC death from transfusion reaction?

A

TRALI

65
Q

how does being cold lead to coagulopathy?

A

causes slowing of enzyme reactions

66
Q

what electrolyte disturbance lead to coagulopathy?

A

hypocalcemia ( Ca required for clotting cascade)

67
Q

how do blood transfusions lead to hypocalcemia?

A

citrate is used in stored blood which binds to calcium after the transfusion and causes hypocalcemia

68
Q

most common bacterial contaminate of blood?

A

GNR (E coli)

69
Q

what is the function of urokinase?

A

convert plasminogen to plasmin