Secondary Hemostasis Flashcards Preview

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Flashcards in Secondary Hemostasis Deck (35)
1

_______ binds the platelet to VWF while _________ binds platelets to platelets (allowing aggregation)

Gp1b

GpIIb/IIIa

2

What is the end product of the coagulation cascade

thrombin

3

what does thrombin do?

convert fibrinogen to fibrin

4

What does fibrin do?

stabilize

5

Where are the factors of the coagulation cascade produced?

the liver

6

What 3 things do coagulation factors require for activation?

1) exposure to activating substance
2) phopholipid surface
3) calcium (derived from platelets)

7

What is the cause of secondary hemostasis?

factor abnormalities

8

What are the clinical features of secondary hemostasis disorders?

deep bleeding (into muscles and joints)

9

What does PT measure?

extrinsic and common pathway

10

What does PTT measure?

intrinsic and common pathways

(intrinsic has more factors involved, measured by the test with more letters)

11

The goal of the coagulation cascade is to produce __________

factor 10 (the perfect 10)

12

What activates factor 12?

subendothelial collagen

13

What activates factor 7?

tissue thromboplastin

14

What initiates the extrinsic pathway?

factor 7

15

What test is a better measurement for the heparin effect?

PTT

16

What test is a better measurement for coumadin effect?

PT

17

What is the cause of hemophilia A?

genetic deficiency in factor 8 (aaaaate)

X-linked recessive (can get de novo mutations)

18

What are the signs and symptoms of patients with disorders of secondary hemostasis?

deep tissue, joint, and postsurgical bleeding

19

What are the lab findings for disorders of secondary hemostasis?

1) HIGH PTT, normal PT
2) LOW factor 8
3) normal platelet count and bleeding time

20

What is the treatment for hemophilia A?

recombinant factor 8

21

What is the cause of hemophilia B?

factor 9 deficiency

22

How does hemophilia B look clinically?

the same as A! (both affect intrinsic pathway)

23

What is the most common coag factor inhibitor?

anti-factor 8
(resembles hemophila A)

24

how do you determine the difference between hemophilia A or coag factor inhibitor disease?

mixing study

25

What is a mixing study?

mix normal plasma with patient plasma

26

What would the mixing study look like for hemophilia A?

can regain coagulation

27

What does mixing study look like for coag factor inhibitor?

FAILS, antibody will hit normal plasma too and it won't bind (cannot correct PTT)

28

What is Von Willebrand's Disease?

defect in VWF (MOST COMMON INHERITED COAG DISORDER)

autosomal dominant

29

What do lab findings look like for VWF disease?

1) HIGH bleeding time
2) HIGH PTT, normal PT
3) abnormal ristocetin test

lack of stability of factor 8 to change the labs but NOT to create clinical problems

30

What is the treatment of VWF disease?

desmopressin (increases release of VWF from Weibel-Palade bodies of endothelial cells)

31

What does vitamin K deficiency result in?

disrupts function of multiple coag factors

vit K is essential for gamma carboxylating factors

32

How does coumadin work?

blockes epoxide reductase

33

Who is prone to vitamin K deficiency?

1) newborns
2) long term antibiotic therapy
3) malabsorption

34

What are 3 reasons why liver failure can lead to bleeding problems?

1) decreased production of coag factors
2) decreased activation of vitamin K by epoxide reductase

35

Why can large volume transfusions lead to bleeding problems?

dilutes coag factors (relative deficiency)