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Flashcards in 02 Hematology Deck (157):
1

which type of VWD is most severe?

III. most severe bleeding

2

where do hemophiliacs tend to bleed?

joints.

3

will newborns with hemophilia A bleed at circumcision?

No. Factor VIII crosses placenta.

4

what is the best coagulation measurement for liver synthetic function?

PT

5

what does prostacyclin do?

decreases platelet aggregation and promotes vasodilation

6

what does thromboxane do?

increases platelet aggregation and promotes vasoconstriction (antagonistic to prostacyclin). also triggers release of calcium from platelets --> exposes GpIIb/IIIa receptor and causes platelet to platelet binding; platelet to collagen binding via Gp1b receptor

7

what are coagulation factors?

cryoprecipitate, FFP, DDAVP

8

what causes type I vWD? what is the treatment?

reduced quantity of vWF, treat with recombinant VIII:vWF, DDAVP, cryo

9

what are PTT and PT in hemophilia A?

high PTT, normal PT

10

what do you need to make sure in hemophilia A people before surgery?

need VIII 100% pre-op, keep at 80-100% for 10-14d after surgery

11

what INR is contraindication for central line placement, percutaneous needle bx, and eye surgery?

INR >1.3

12

what INR is contraindication for surgical procedures?

INR > 1.5

13

what are the players in fibrinolysis?

tissue plasminogen activator, plasmin, alpha-2 antiplasmin.

14

what causes type III vWD? what is Rx?

complete vWF deficiency (rare). Rx is VIII:vWF, cryoppt. (DDAVP doesn't work)

15

what is active clotting time (ACT) for routine anticoagulation and for cardiopulmonary bypass?

150-200 sec for routine, >460 for cardiopulm bypass

16

what does thrombin do?

it is the key to coagulation. converts fibrinogen to fibrin and fibrin split products, activates factors V and VIII, activates platelets

17

should you aspirate hemophiliac joint bleeds?

no! give ice, keep joint mobile with range of motion, give factor VIII concentrate or cryoppt

18

what test do you do to figure out VWD?

ristocetin test (bleeding time)

19

where does thromboxane come from?

platelets

20

what are the symptoms of hemophiliacs?

epistaxis, ICH, hematuria. treat with recombinant factor VIII or cryo

21

what should PTT be for routine anticoagulation?

60-90 sec

22

can PT and PTT be normal in VWD?

yes. can be nl or abnl

23

what is the most common cause of surgical bleeding?

incomplete hemostasis

24

what is the function of vWF?

links GpIb receptor on platelets to collagen

25

what does tissue plasminogen activator do?

it is released from endothelium and converts plasminogen to plasmin

26

where does prostacyclin come from?

endothelium

27

when does FFP take effect and how long does it last?

immediately, lasts 6 hrs

28

what does alpha-2 antiplasmin do?

it is a natural inhibitor of plasmin, released from endothelium

29

what is definition of hemophilia A?

VIII deficiency

30

what does ATIII do?

key to anticoagulation, binds and inhibits thrombin, inhibits factors IX, X, XI, heparin activates AT-III (up to 1000x normal activity)

31

which is the only factor not synthesized in liver?

factor VIII. it's synthesized in the endothelium

32

what does PTT measure?

measures most factors except VII and XIII (does not pick up factor VII deficiency). also measures fibrinogen.

33

what do DDAVP and conjugated estrogens do?

cause release of VIII and vWF from endothelium. similar effect as cryoppt

34

what does plasmin do?

degrades factors V, VIII, fibrinogen, fibrin --> lose platelet plug

35

what does protein S do?

vitamin K dependent, protein C cofactor

36

what does protein C do?

vitamin K dependent. degrades factors V and VIII, degrades fibrinogen

37

what does PT measure?

II, V, VII, X, fibrinogen.

38

what is in FFP?

high levels of coagulation factors, protein C, S, and AT-III

39

what is the normal half life for RBCs, platelets, and PMNs?

RBC: 4 months, platelets 7d, PMNs: 1-2d

40

what is another name for factor II?

prothrombin

41

which factor has the shortest half life?

factor VII

42

what is in cryoppt? when is it used?

high vWF-VIII. used for vWF disease and hemophilia (factor VIII deficiency). also has high levels of fibrinogen.

43

what factor is missing in hemophilia B?

IX

44

how is hemophilia A transmitted?

sex-linked recessive

45

what causes type II vWD? what is the treatment?

defect in vWF molecule itself, vWF does not work well. Rx is recombinant VIII:vWF, cryoppt

46

how many hours does vitamin K take to have effect?

6hrs

47

what is the most common congenital bleeding disorder?

VWD

48

which proteins in anticoagulation cascade vitamin K dependent?

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

49

what is the most common type of VWD?

Type I (70% of cases), only mild sx

50

which factor is labile, lost activity in stored blood, and who continues to have activity in FFP?

factors V and VIII

51

what causes glanzmann's thrombocytopenia?

GpIIb/IIIa receptor deficiency on platelets (can't bind to each other). Fibrin normally links GpIIb/IIIa receptors together. Rx is platelets.

52

what causes bernard soulier?

Gp1b receptor deficiency on platelets (can't bind collagen). vWF normally links GpIb to collagen. Rx is platelets

53

when does ASA need to stop before surgery?

7 days

54

what are the platelet disorders?

acquired thrombocytopenia, glanzmann's thrombocytopenia, bernard-soulier, uremia

55

how does uremia induce thrombocytopenia? what is the treatment?

inhibits platelet fxn. Rx is hemodialysis (1st), then DDAVP, platelets

56

does LMWH have a decreased risk of HIT?

yes

57

what is PT and PTT in factor VII deficiency?

prolonged PT, normal PTT.

58

what are findings in DIC?

decreased platelets, low fibrinogen, high fibrin split products, high D-dimer, prolonged PT and PTT

59

what are lab findings in pts taking ASA?

prolonged bleeding times

60

what causes acquired thrombocytopenia?

H2 blockers, heparin

61

how is hemophilia B transmitted?

sex linked recessive

62

what is treatment for DIC?

treat underlying cause (eg sepsis)

63

high or low doses of heparin to cause HIT?

can occur with low

64

what is treatment for HIT?

stop heparin, start argatroban (direct thrombin inhibitor) to anticoagulate

65

what are PT and PTT in hemophilia B pts?

prolonged PTT, normal PT. same as hemophilia A.

66

how do you treat hemophilia B?

recombinant factor IX, or FFP

67

what is treatment for factor VII deficiency?

recombinant factor VII concentrate or FFP

68

how does HIT cause thrombocytopenia?

antiplatelet antibodies (IgG PF4 antibody) resulting in platelet destruction, platelet aggregation (thrombosis), forms a white clot.

69

what levels of IX do you need in a hemophilia B pt before surgery?

100% preop, keep at 30-40% for 2-3d after surgery

70

what are the three initial responses to vascular injury?

vasoconstriction, platelet adhesion, thrombin generation

71

what is the extrinsic pathway?

exposed collagen + prekallikrein + HMW kiniogen + factor XII activate XI --> activate IX, then add VIII --> activate X, then add V --> convert prothrombin (factor II) to thrombin --> thrombin then converts fibrinogen to fibrin

72

what does fibrin do?

links platelets together (binds GpIIb/IIIa molecules) to form platelet plug --> hemostasis

73

what is the intrinsic pathway?

tissue factor (injured tissues) + factor VII --> activate X, then add V --> convert prothrombin to thrombin --> thrombin then converts fibrinogen to fibrin

74

what does tissue factor inhibitor do?

inhibits factor x

75

what causes warfarin induced skin necrosis?

when pt placed on coumadin without being heparinized first

76

what causes warfarin-induced skin necrosis?

short half life of proteins C and S --> decrease in levels compared with the procoagulation factors; results in relative hyperthrombotic state.

77

who is especially susceptible to warfarin-induced necrosis?

pts w relative protein C deficiency

78

how do you treat warfarin-induced skin necrosis?

heparin if it occurs. prevent by placing pt on heparin before starting warfarin

79

what are the elements in deveoping venous thromboses? what is it called?

virchow's triad: stasis, endothelial injury, hypercoagulability

80

what are the key elements in development of arterial thrombosis?

endothelial injury

81

what are risk factors for developing arterial thromboses?

stasis, venous injury, hypercoagulability

82

what is post-op DVT treatment (1st, 2nd, 3rd lines)?

1st: warfarin for 6 months. 2nd: warfarin for 1 yr. 3rd or significant PE: warfarin for lifetime

83

when are greenfield filters given?

1. contraindications to anticoagulation, 2. documented PE while on anticoagulation, 3. free-floating IVC, ilio-femoral, or deep femoral DVT, 4. recent pulm embolectomy

84

when can temporary IVC filters be given?

for pts at high risk for DVT (head injury on prolonged bed rest)

85

are thrombolyics proven for treatment of PE?

no

86

if pt is in shock from PE despite massive inotropes and pressors, what do you do?

go to OR; otherwise give heparin or suction catheter-based intervention

87

where do most PEs arise?

ilio-femoral region

88

what are the procoagulant agents (anti-fibrinolytics)?

E-aminocaproic acid (Amicar)

89

what are the anticoagulation agents?

(warfarin, SCDs, heparin, LMWH, argatroban, bivalirudin, hirudin, ancrod

90

how does warfarin work?

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

91

how do SCDs cause anticoagulation?

improves venous return, induces fibrinolysis w compression (release of tPA from endothelium)

92

how is heparin reversed?

protamine

93

how does protamine work?

binds heparin

94

what should PTT be when treating w heparin?

60-90 seconds. (mnemonic is half life heparin 60-90 min)

95

how is heparin cleared?

reticuloendothelial system

96

what is the reticuloendothelial system?

mononuclear phagocyte system

97

what are the risks of taking heparin for a long time?

osteoporosis, alopecia

98

can heparin be used during pregnancy? warfarin?

heparin doesn't cross placental barrier, warfarin does

99

what does protamine cross react with?

NPH insulin

100

what does cross reaction of protamin and NPH insulin give you?

protamine reaction (hypotension, brady, decreased heart function)

101

what are examples of LMWH?

enoxaparin, fondaparinux

102

how does LMWH work? what are the advantages?

LMWH binds and activates AT-III, increases neutralization of JUST Xa and thrombin--> NOT reversed w protamine. advantage is lower risk of HIT (compared to unfractionated heparin)

103

how does argatroban work?

it is a reversible direct thrombin inhibitor

104

how is argatroban metabolized?

liver

105

what is argatroban half life?

50 minutes

106

when is argatroban used?

in pts with HITT

107

how does bivalirudin work?

reversible direct thrombin inhibitor.

108

how is bivalirudin metabolized?

proteinase enzymes in blood

109

what is bivalirudin's half life?

25 minutes

110

where does hirudin come from?

leeches

111

how does hirudin work?

irreversible direct thrombin inhibitor, most potent direct inhibitor of thrombin

112

what is the risk of hirudin?

high risk for bleeding complications

113

what is ancrod and how does it work?

malayan pit viper venom; stimulates tPA release

114

of argatroban, bivalirudin, hirudin, which ones are reversible and which are irreversible direct thrombin inhibitors?

argatroban and bivalirudin are reversible

115

what are the thrombolytics?

streptokinase, urokinase, and tPA

116

what do thrombolytics do?

activate plasminogen

117

what is the treatment for thrombolytic overdose?

E-aminocaproic acid (Amicar)

118

what are the minor contraindications for thrombolytic use?

minor surgery, recent CPR, AF w MV dz, bacterial endocarditis, hemostatic defects (ie renal or liver disease), diabetic hemorrhagic retinopathy, pregnancy

119

what are the major contraindications for thrombolytic use?

recent (<10d) surgery, organ biopsy, obstetric delivery, left heart thrombus, active PUD, recent major trauma, uncontrolled HTN, recent eye surgery

120

what are the absolute contraindications for thrombolytic use?

active internal bleed, recent CVA or neurosurgery (<3 mo), intracranial pathology, recent GI bleed

121

what should hct and platelets be before surgery in pts with PCV?

hct <400 before surgery

122

which types of VWD are autosomal dominant and which are autosomal recessive?

I and II are autosomal dominant, III is autosomal recessive

123

what are the initial events to thrombus formation?

1. platelet adhesion
2. shape change
3. granule release
4. recruitment
5. hemostatic plug
6. collagen exposure

124

what do you need to follow when using thrombolytics? how high should it be?

fibrinogen levels should be >100. if <100, associated with risk and severity of bleeding

125

how does heparin work?

binds and activates anti-thrombin III (1000x more activity)

126

how does ASA work?

inhibits cyclooxygenase (COX) in platelets and decreases TXA2.

127

can platelets resynthesize COX?

no. they dont have DNA

128

what is the treatment for factor V leiden?

heparin, warfarin

129

what is the treatment for protein C or S deficiency?

heparin, warfarin

130

how does factor V leiden mutation cause problems?

causes resistance to activated protein C; the defect is on factor V.

131

what is the most common congenital hypercoagulability disorder?

factor V leiden mutation (30% of spontaneous venous thromboses)

132

how high should platelets be before and after surgery?

>50,000 before, >20,000 after

133

when does coumadin need to stop before surgery? what do you need to consider in pts who require coumadin during this time?

stop 7 days before surgery, consider bridge to heparin

134

if a pt has epistaxis, what diseases are most likely?

vWF deficiency and platelet disorders

135

what is a consider in prostate surgery in terms of bleeding?

can release urokinase, which activates plasminogen --> thrombolysis.

136

how are most patients with bleeding disorders revealed?

tooth extraction or tonsillectomy

137

what is treatment for plavix overdose?

platelets

138

what ist he treatment for prothrombin gene defect G202010 A?

heparin, warfarin

139

what is the treatment for hyperhomocysteinemia?

folate and b12

140

what causes APLAS?

antibiodies to cardiolipin and lupus anticoagulant (phospholipids)

141

what is the most common factor causing acquired hypercoagulability?

tobacco

142

what is treatment for APLAS?

heparin, warfarin

143

what are causes of acquired hypercoagulability?

tobacco, malignancy, inflammatory states, inflammatory bowel dz, infections, oral contraceptives, pregnancy, RA, post-op, myeloproliferative disorders

144

how do you diagnose APLAS?

prolonged PTT (corrected with FFP), russell viper venom time, false pos RPR test for syphilis

145

how does cardiopulmonary bypass cause hypercoagulation? what can you do to prevent?

factor XII (hageman factor) is activated. Heparin prevents it.

146

what is the treatment for dysfibrinogenemia, dysplasminogenemia?

heparin, warfarin

147

how does polycythemia vera cause cause clots? what is treatment?

defect in platelet fxn, can get thrombosis. Rx: phlebotomy, ASA

148

what is the treatment for antithrombin III deficiency?

heparin does not work in these pts. Rx: recombinant AT-III concentrate or FFP (highest concentraiton of AT-III) followed by heparin, then warfarin

149

what happens to coags in APLAS?

prolonged PTT...but they are hypercoagulable

150

do all pts with APLAS have SLE?

no

151

what is special about factor X?

convergence point between intrinsic and extrinsic and is common for both paths.

152

what is the treatment for prostate surgery bleeding?

E-aminocaproic acid (amicar)

153

what is the prothrombin complex?

tissue factor (injured tissues) + factor VII --> activate X, then add V --> convert prothrombin to thrombin --> thrombin then converts fibrinogen to fibrin

154

what does XIII do?

helps crosslink fibrin.

155

what is heparin half life?

60-90 minutes

156

what are the thrombolytic agents?

streptokinase, urokinase, tPA

157

when does clopidogrel (plavix) need to stop before surgery? how does it work?

stop 7d before surgery. it is an ADP receptor antagonist.