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M2 Hematology > 8. Coagulapathies > Flashcards

8. Coagulapathies Flashcards

1
Q

what is the most common hereditary bleeding disorder?

A

vWD. 1% of population.

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2
Q

vWD is synthesized as proteins of how many units? what happens subsequently?

A

synth as monomers. motidied and turned into mulitmers, then cleaved into multimers of various sizes by ADAMTS13.

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3
Q

three functions of vWD?

A
  • tethers platelets to subendo in vascular injury
  • chaperones/protects FVIII in blood, lengthens half-life
  • localizes FVIII at site of injury
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4
Q

three categories of vWD?

A

type 1: low levels of wWD
Type 2: qualitative problem with protein. abnormal structure so doesn’t work well. normal QUANTITY of vWD
Type 3: complete absence of protein
Acquired: antibody against it

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5
Q

Type 1, 2, 3, acquired vWD: what is most common?

A

Type 1

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6
Q

what pattern/type of bleeding is most common with vWD?

A

muco-cutaneous. epistaxis, gums, bruising

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7
Q

PT, PTT tests normal or abnl with vWD?

A

PT normal

PTT can be normal or prolonged

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8
Q

Platelet function tests abnl or nl with vWD?

A

abnormal. prolonged PFA-100, prolonged bleeding time, abnl aggregation with stimulation by ristocetin

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9
Q

what is DDAVP? what does it do?

A

desmopressin.

stimulates release of vWF and FVIII from endothelial cells

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10
Q

how is DDAVP delivered?

A

intranasally or by IV.

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11
Q

should we use DDAVP in Type 2 vWD?

A

NO because you’d just stimulate release of more abnormal/nonfunctional platelets

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12
Q

will DDAVP work for Type 3 vWD?

A

no, you don’t have any vWF at all. give replacement factor.

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13
Q

in the female carrier state of hemophilia A of B, what symptom is common?

A

menorrhagia

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14
Q

Mild Hemophilia A: factor level? PTT? bleeding?

A

factor level: 5-40%
PTT may be normal
bleeding with trauma, surgery

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15
Q

Moderate Hemo A: factor level? PTT? bleeding?

A

factor level: 2-5%
PTT prolonged
bleeding sometimes spontaneous

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16
Q

Severe Hemo A: factor level? PTT? bleeding?

A

factor level: <1%
PTT prolonged
bleeding: spontaneous = common

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17
Q

why may bleeding be delayed in Hemophilia?

A

can form primary platelet plug, cannot form secondary coagulation/stabilization

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18
Q

what is the biggest problem with the clotting cascade in Hem A or B?

A

The Thrombin Burst is diminished, can’t make a good fibrin clot.

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19
Q

Labs for Hem A and B: PT? will PTT correct with a mixing study?

A

PT normal

PTT will correct with a mixing study

20
Q

Tx of hemophilia?

A

recombinant VIII and IX

21
Q

what other treatment might FVIII def respond to?

A

DDAVP

22
Q

what is an inhibitor?

A

antibody to the coag factor that is being replaced.

23
Q

in what cases is prophylactic factor replacement used with?

A

severe hemophilia only.

24
Q

how is an inhibitor treated?

A

use of bypassing agents, ie FVIIa, trying to drive the extrinsic pathway by mass action.

25
Q

labs in acquired hemophilia or with an inhibitor: PFA-100, bleeding time? PT? PTT? mixing study? FVIII level?

A
  • PFA and bleeding time will be normal
  • PT normal
  • PTT prolonged
  • mixing study does NOT correct
  • FVIII level low
26
Q

what is fibrinolytic bleeding?

A

bleeding is delayed (12-24 hrs) because clot/fibrin is broken down prematurely by PLASMIN. bleeding is often mucocutaneous/oropharyngeal

27
Q

what are some of the causes of fibrinolytic bleeding?

A

hereditary causes are very rare. more common = cancer, lifer disease, DIC, release of plasminogen factors from prostate surg.

28
Q

fibrinolytic bleeding: lab results: PT? PTT? D-Dimer?

A

PT may be prolonged
PTT may be prolonged
D-Dimer may be increased

29
Q

what is D-Dimer?

A

breakdown product when plasmin breaks down fibrin (ie clot breakdown)

30
Q

why is d-dimer elevated in DIC but not disorders of fibrinolysis?

A

for disorders of fibrinolysis, it is the fibrinogen in the blood that is broken down, not the fibrin in clots. fibrinogen does not yield D-dimer as a breakdown product. with DIC, it is the FIBRIN clots that are broken down. yields D-Dimer.

31
Q

why is vitamin K deficiency a problem?

A

it is required for gamma-carboxylation of coag factors, makes coag binding more efficient.

32
Q

what is the relationship between Vit K and warfarin?

A

warfarin blocks epoxide reductase, so Vit K is not activated, and coag factors are not gamma-carboxylated, don’t work as well.

33
Q

generally, what does Vit K def lead to?

A

bleeding disorder

34
Q

what does warfarin do?

A

anticoagulation

35
Q

labs in Vit K deficiency: PT? PTT? mixing study? platelet function studies? levels of F 2, 7, 9, 10? level of FV?

A 
PT prolonged
PTT prolonged
mixing study will correct
platelet function studies normal
2, 7, 9, 10 levels decreased
FV level normal
36
Q

how can we tell the difference between Vit K def and liver failure?

A

FV level: normal with Vit K def, and low with liver failure

37
Q

Treatment of Vit K def?

A

give Vit K (oral, IV)
fresh frozen plasma + vit K (emergency)
Prothrombin complex: F2, 7, 9, 10

38
Q

where are coag factors synthesized?

A

liver

39
Q

in addn to liver, where is FVIII also synthesized?

A

vasc endothelial cells. so FVIII preserved with liver dz.

40
Q

where are fibrinolytic factor inh synthesized?

A

liver

41
Q

in general, liver disease results in bleeding or clotting?

A

bleeding often predominates but there can also be clotting. Forces in both directions, overall clotting diathesis.

42
Q

in terms of what is happening to synthesis and clearance of factors, liver disease causes what?

A

liver disease will lead to decr synthesis of anticoagulant and fibrinolytic factors as well as decr clearance of activated coag factors

43
Q

what anticoag and fibrinolytic factors are synth by the liver?

A

Protein C, S, antithrombin, plasminogen. also, activated coag factors are cleared by liver

44
Q

Define DIC

A

acquired coag disorder that occurs when the normal hemostatic balance is disturbed, primarily resulting in excessive thrombin formation

45
Q

in DIC, what does intravascular thrombin generation lead to?

A

conversion of fibrinogen to fibrin in the systemic circulation, activation of platelets

46
Q

DIC: once fibrinogen has been converted to fibrin in systemic circ and platelets have been activated, what are compensatory reactions?

A

activation of protein C

incr in plasmin and fibrinolysis

M2 Hematology (15 decks)

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