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Haem/Onc > Haemostasis, Acquired, ASPHO > Flashcards

Haemostasis, Acquired, ASPHO Flashcards

1
Q

rupture in endothelial lining–> blood exposed to subendothelial protiens, including___ adn ___ ___

A

collagen; tissue factor

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2
Q

3 parts of primary hemostasis?

A

subendothelium
plts
vWF

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3
Q

2 collagen d/o’s

A

Ehlers Danlos

Osteogenesis Imperfecta

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4
Q

how do you dx Ehlers Danlos?

A

on physical exam:

  • skin tenting
  • hypermobility
  • genetic testing
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5
Q

osteogenesis imperfecta: characteristics?

A
  • easy fractures
  • blue sclera
  • easy bruising due to collagen defect
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6
Q

all coag factors made inside of the liver; which are also made outside, and where else?

A

F5 (megakaryocytes)
F8 (endothelial cells)
F13 (macropahges)

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7
Q

where is VWF made?

A

endothelial cells

megakaryocytes

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8
Q

which hemostatic factors are normal or high in infancy?

A

fibrinogen (2)= NORMAL
F8: normal-high
VWF: normal-high
all others are low!–> near normal around 6 months

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9
Q

shortest half life coag factor? length?

A

F7; 3-6 hours

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10
Q

coag factor with longest half life? how long?

A

F13; 10 days

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11
Q

1/2 life of F8?

A

8-12 hours

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12
Q

1/2life of F9?

A

22 hours

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13
Q

contact activating system includes? order? they are called the ___ ___ because they get activated when blood contacts an ___ ___, eg?

A
  • Prekallikrein
  • HMW kininogen
  • Kallikrein
  • F12 and activated F12
  • F11

PK–> K via HMW kininogen enzyme; K–> F12, which gets activated to F12a, which then–> PK

contact factors
artificial surface

blood entering a tube/blood touching a CVC

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14
Q

12->12A–> activates 11–> 11A, and then waht acts as cofactor for activation of 9-> 9A by 11A?

A

8A

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15
Q

what is a cofactor for 10a? for what reaction?

A

5A…for reaction for prothrombin (2)-> thrombin (2a)

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16
Q

what does thrombin (2a) do?

A
  • cleaves fibrinogen (1) to fibrin

- also activates 13-> 13A

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17
Q

what does 13a do?

A

catalyzes fibrin-> cross-linked fibrin clot

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18
Q

what catalyzes 7-> 7a?

A

tissue factor

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19
Q

what does 7a do?

A

catalyzes 10-> 10a

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20
Q

among the contact factors, only ___ def is associated with bleeding

A

F11

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21
Q

do all pts with F11 def bleed?

A

yes

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22
Q

how does the contact activation system link to the complement system?

A

Kallekrein activates C3; F12a activates C1

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23
Q

kallekrein activates what 3 things?

A

F12
C3
bradykinin/kinin (inflammation)

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24
Q

rupture endothliuem–> ___ becomes available and does what? issue with this? solution?

A

TF, activates circulating F7-> 7a…this cascade only produces a very small amount of thormbin because F8 adn 9 not involved….thrombin initiates a feedback loop! activate 8-> 8a and 5-> 5a, which are the main catalysts of the coag cascade!

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25
Q

phsyiological role of 7a outside of the classic cascade? role of f11 here?

A

7a activates 9-> 9a…not really used! unless situation of ++ trauma or stress! can get activated by thormbin…this is why F11 def pts only really bleed with trauma or surgery

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26
Q

TAFI=?

A

thrombin-activatable fibrinolysis inhibitor

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27
Q

role of TAFI?

A

gets activated by thrombin to inhibit fibrinolysis

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28
Q

all the clotting roles of thrombin=2a?

A

activates Fs 1 (fibrinogen), 5, 8, 11, 13, TAFI-TAFIa, platelets

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29
Q

what does thrombomodulin do?

A

it modulates the effect of thrombin. NEAR the area of endothelial rupture, thrombomodulin converts thrombin=2a from a procoagulant protein to an anticoagulant protein. Thrombin+Thrombomodulin together will activate Protein C–> activated protein C

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30
Q

what does activated protein c do?

A

inhibits 5a and 8a

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31
Q

fibrinogen on which chrom?

A

4

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32
Q

genes that encode fibrinogen?

A

FGA, FGB, FGG to encode Aalpha chain, BBeta chain, gamma chain respectively–> all come together to make fibrin molecule

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33
Q

where is fibirnogen’s thrombin binding site? what happens when that site gets cleaved by thrombin?

A

alpha chain…when that’s cleaved, it allows for a linkage between the beta and gamma chains…then lose fibrinopeptide b and a–> FIBRIN

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34
Q

how does fibrin interact with clot?

A

binds plts via GPIIbIIIa:) 2b3a

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35
Q

fibrinogen is an __ __ ___ –> elevated ___

A

acute phase reactant; ESR

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36
Q

test for fibrinogen def how?

A
  • measure funcitonal fibrinogne via Clauss method

- elevated PT, PTT, thrombin time will be prolonged when fibrinogen <1g/L

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37
Q

2 tests for dysfibrinogenemia?

A

thrombin time

fibrinogen antigen to activity ratio

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38
Q

how can you test for fibrinogen and dysfibrinogen in prsence of heparin (because thrombin time affected by heparin)

A

reptilase time

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39
Q

test F13 how?

A
  • clot solubility assay (iwth urea or acetic acid)…qualitative test that is normal or not normal…sensitivie for only very low levels of F13, <5%
  • chromogenic assay= more sensitive, not as readily available
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40
Q

F13 associated iwth __ __ __ can also get __ __ of __ __, just like with ___ __ ___

A

poor wound healing
delayed separation of umbilical stump
leukocyte adhesion def

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41
Q

natural inhibitors of coag? 4

A

Tissue factor pathway inhibitor
Antithrombin
Protein C
Protein S

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42
Q

Tissue factor pathway inhbibitor acts where?

A

blocks F7-> 7a

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43
Q

antithrombin acts where?

A

acts on 10a and 2a= thrombin

44
Q

Protein Ca acts where?

A

blocks 5a, 8a

45
Q

protein s acts where?

A

cofactor for protein Ca to block 5a and 8a

46
Q

where does protein s come from

A

secreted from endothelial cells

47
Q

what lyses the clot? where does it come from?

A

TPA= tissue plasminogen activator; endothelial cells

48
Q

PAI-1 does what?

A

plasminogen activator inhibitor -1; blocks TPA

49
Q

heparin-sulfate does what?

A

works with antithrombin to inhibit thrombin and 10A

50
Q

plasminogen–> ? what 2 enzymes can mediate this?

A

plasmin; tissue plasminogen activator= tPA or urine plasminogen activator= uPA=urokinase

51
Q

tpa is found where?

A

blood, saliva, GI secretions

52
Q

urokinase found where?

A

urine

53
Q

plasmin does what?

A

dissolves fibrin clot–>fibrin split products, d-dimer

54
Q

what inhibitors tpa?

A

PAI-1

55
Q

what inhibitrs plasmin?

A

alpha2-antiplasmin

56
Q

waht does TAFIa do?

A

inhibits plasmin’s ability to lyse a clot

57
Q

fibrinolysis increased in what 3 situations?

A
  • DIC
  • venous thrombosis
  • liver disease
58
Q

issues with the fibrinolytic system where you would expect to get thrombosis?

A

plasmin def, tpa def

59
Q

fibrinolytic inhibitors…defs–> bleeding?

A

PAI-1 deficiency

-alpha 2-antiplasmin deficiency

60
Q

fibrinolytic drug?

A

tPA

61
Q

2 uses for tPA?

A
  • tx of arterial, venous clots

- used to tx CVC lumen occlusions

62
Q

two antifibrinolytic drugs? what are analogs of? how do they work?

A

epsilon-aminocaproic acid and TXA; analogs of lysine; they block plasmin’s binding site for fibrin

63
Q

why doesn’t f13 prolong PTT, PT?

A

these assays don’t require fibrin to be crosslinked..just generated!

64
Q

thrombin time is abnormal in waht?

A

hypofibrinogenmia
afibrinogenemia
dysfibrinogenemia

65
Q

If PTT but not PT prolonged, otehr than Defs in 8,9,11,12 ddx? 4

A

prekalekrein def
HMW K def
circulating anticoagulant
heparin effect

66
Q

PT and PTT prolonged: other than liver disease, DIC, fibrinogen issue, vit k def, ddx? 3

A

warfarin
heparin effect
circulating anticoagulant

67
Q

vit k sources?

A

diet

gut flora syntehsizes vit k too

68
Q

how does vit k acivate 2, 7, 9, 10?

A

vit k–> vit k hydroxyquinone via vit k epoxide reductase…vit k hydroxyquinone then adds a carboxyl group at gamma position to fs 2,7,9,10 via vit k gamma-glutamyl carboxylase

69
Q

test you can do for vit k def?

A

PIVKA= proteins induced in vitamin k absence..comes back really high if vit k def!

70
Q

how does warfarin work?

A

inhibits vit k epoxide reductase, which is needed for converting vit k epoxide-> vit k and for vitk -> Vitk vit k hydroxyquinone, which activates the coag factors

71
Q

how many days does it take for warfarin to become therapetuic?

A

5-7 days

72
Q

what if you have an early rise in INR before 5-7 days?

A

this is probably just due to drop in factor 7…however, takes much longer for f10 to drop so don’t stop heparin yet…need 5-7 days

73
Q

warfarin should alwasy be overlapped with another anticoagulant until INR is therapeutic for __ ___days

A

2 consecutive

74
Q

1 possible complication of warfarin use other than bleeding? why?

A

skin necrosis; early drop in protein C after warfarin starts

75
Q

effects of ddavp? (3)

A
  • increases VWF
  • increases F8 (probably due to increased VWF)
  • increases tPA release
76
Q

bleeding not used anymore but tests what?

A

primary hemostasis

77
Q

PT, PTT, TT go into what kind of tube?

A

blue top tube= citrate tube

78
Q

PT, PTT, TT sample relies on proper ratio of ___ to ___ (__:__)

A

plasma to citrate; 9:1

79
Q

what can lead to artifacts in PT, PTT, TT? 5

A
  • tube not properly filled–> little plasma–> falsely high results
  • pateint with polycytemia= little plasma–> falsely high
  • severe anemia= too much plasma–> falsely low (normal) results
  • not processed false enough (temp issue)–> falsely high
  • difficult draw–> clotting starts too early–> false elevation
  • heparin in sample–> false elevation
80
Q

3 heme related acute phase reactants?

A

fibrinogen
f8
vwf

81
Q

how to DIC work?

A

inciting event–> activation of coagulation via circulating tissue factor–> consumption of clotting factors and plts (-> bleeding) AND consumption of anticoagulant clotting factors + disurption of endothelial anticoagulant surface–> thrombosis–> fibrinolysis

82
Q

4 causes of DIC?

A
  • sepsis
  • kasabach merrit syndrome
  • malig, eg APML
  • Trauma, eg burns
  • severe hemolysis
  • severe protein c deficiency
83
Q

what is purpura fulminans?

A

possible presentation of DIC; severe skin necrosis due to microvascular thrombus, acute onset

84
Q

clinical features of DIC?

A
  • bleeding/bruising/petechiae
  • purpura fulminans, organ dysfucntion due to clots
  • hemolytic anemia
85
Q

5 lab findings in DIC?

A 
high INR
high PTT
low fibirnogen 
low plts
elevated d-dimer
elevated fibrin degrationi products
elevated fibrinopeptide A and B
decreased prot C, S, antithrombin
86
Q

Neonates are physioloigclaly deficient in what 3 things? how does this related to DIC?

A

protein C
protein S
AT
impairs protective mechanism for DIC

87
Q

DIC tx?

A
  • tx underlying disease!!!!
  • plt transfusion not generally indicated due to risk for increased thrombosis
  • FFP (balance of pro-clotting and anti-clotting factors), but no evidence that it affects outcome
  • cryo for low fibrinogen if bleeding occurs..no clear evidence of benefit however
88
Q

Does human milk have vitamin K?

A

has little to none

89
Q

vit k def bleeding in newborn: 3 types and timing?

A

early: first 24 hours
classical 2-7 days
late 1-6 mos, even later

90
Q

cause of early vit k def bleeding?

A

maternal drugs: warfarin, anticonvulsants

91
Q

risk factor for classical vit k def bleeding?

A

none (all babies at risk)

92
Q

risk factors for late vit k def bleeding? 3

A

CF, liver disease, chronic antibiotic use

93
Q

tx if infant has ICH secondary to vit k def?

A

Prothrombin complex conetrates immediately, also vit k

94
Q

3 reaosns why liver disease–> bleeding?

A

most factors made in liver; low plts due to hypersplenism, hyperfibrinolysis due to increased tPA release from endohtelial cells

95
Q

which organ clears d-dimers?

A

liver…in liver disease, d-dimers will be high

96
Q

2 specific factor inhibitors and cause?

A

f8 inhibitor: secondary to autoabs

f5 inhibitor secondary to exposure to bovine thrombin

97
Q

can f8 autoabs in mom be transplacentally passed to baby?

A

yes

98
Q

mother can passively transfer lupus Ac to baby…can often lead to which type of thrombosis?

A

Renal vein thrombosis

99
Q

major cuase of LAC?

A

viral infection

100
Q

LACs tend to be ___ and ___

A

asyptomatic and transient

101
Q

rarely, pts with LAC also have acquired what?

A

hypoprothrombinemia…acquired loss of F2 due to increased clearance…“lupus anticoagulant hypoprothrombinemia syndorme”

102
Q

lupus anticoaguant assay AKA?

A

dilute Russel’s viper venom time

103
Q

how does dRVVT work?

A

2 steps:
1-run teh dRVVT on patient sample..if abnormal, proceed to confirm with step 2
2- re-run, but with exogenous exogenous phospholipid, which should CORRECT teh abnormality seen

104
Q

what’s an abnormal dRVVT result?

A

screening:confirmatory test >1.2

105
Q

how to manage LAC?

A

repeat assay in 6-12 weeks…no specific therapy indicated; observation

106
Q

tx for lupus anticoagulant hypoprothrombinemia sndrome?

A

replace prothrombin with PCC for bleeding…observation= usually transient

Haem/Onc (30 decks)

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