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Flashcards in Hemostasis Deck (33):
1

What are the major players in hemostasis?

Platelets
Endothelial cells
Coagulation

2

What are the three things that contribute to thrombosis?

Endothelial injury
Abnormal blood flow
Hypercoaguability

3

Hypocoagulation is displayed as:
Hypercoagulation is displayed as:

Hemorrhage
Thromboembolic disorders

4

Hemostasis and coagulation are regulated by what 3 componenets?

Vascular wall: endothelial cells have procoagulant and anti-coagulant on them
Platelets
Coagulation cascade

5

What are the steps of hemostasis?

Vasoconstriction: very transient and fast
Primary hemostasis: hemostatic plug formed; reversible
Secondary hemostasis: polymerizes fibrin; irreversible

6

What is the endothelial derived vasoconstrictor that follows injury to vessel wall?

Endothelin

7

What two things initate the coagulation cascade at secondary hemostasis?

Tissue Factor (F3) + activated platelets

8

What are some properties of endothelial cells that are prothrombotic?

Produce vWF
Synthesize TF
Antifibrinolytic properties: prevents fibrinolysis

9

What are some properties of endothelial cells that are antithrombotic?

Have heparin like modules
Thrombomodulin binds thrombin
Tissue factor pathway inhibitor: deactivates TF, F7 and F10

10

What is it again that resists shear forces?

vWF and GP2a

11

What are the three pathways of the coagulation cascade?

Extrinsic
Intrinsic
Common

12

What is the extrinsic pathway?

Starts with Factor 3 (Tissue factor)
Activates F7 --> F10 (Common pathway) AND F9 (Intrinsic)

13

What is the intrinsic pathway?

Factor 12 --> Factor 11 --> F9 --> F8 (co-factor) --> F10 (Common)

14

What is the common pathway?

F10 --> F5 --> F2 (thrombin)

15

Cats often lack what factor?

Factor 12; not a big deal as F7 can still activate the intrinsic pathway via F7 --> F9

16

What are the vitamin K dependent factors?

Factors 2,7,9,10 Protein C and Protein S

17

PT test looks at what? What % has to be decreased for this to prolong test?

Extrinsic and common pathways
>70% of factors have to be decreased

18

T/F If not available, human reference intervals are okay to substitute for PT and PTT tests

FALSE; they should NEVER be used

19

PTT test looks at what?

Intrinsic and common pathways

20

D-Dimers test is a specific indicator for what?

Secondary fibrinolysis

21

What is an increased D-Dimers indicate?

Hemorrhage and thrombosis
Thromboembolism

22

What species can a D-Dimers test be run for? Which should it not be run for?

Dogs and horses

Don't use in cats

23

What are FDPs? When do we see an increase in these?

Fibrin degradation products
Increased in DIC, inflammation and liver DZ

24

What factors play a role in fibrinolysis?

tissue Plasma Activator (tPA)
Antithrombin 3
Protein C and S
Tissue Factor Inhibitor

25

Antithrombin III is a protein that inhibits what?

Thrombin
Factors 7, 11, 9, and 10

26

Proteins C and S inhibit what?

Factors 7 and 5 (co-factors)

27

Hemophilia A is a deficiency in what?

Factor 8; affects the intrinsic pathway

28

Hemophilia B is a deficiency in what?

Factor 9

29

Hageman's disease is a deficiency in what factor?

Factor 12

30

Factor 11 deficiency can be seen in what species?

Dogs and Holstein cattle

31

How does Factor 7 deficiency present?

Likely in dogs with easy bruising

32

T/F Disseminated Intravascular Coagulation is a primary disease

FALSE; it is secondary to other pathology

33

No single test is a determinant for DIC; what are 3 or more of the criteria that fit for DIC?

Decreased platelets (mild to severe)
PRolonged PT or PTT
Increased FDPs or D-Dimers
Decreased Fibrinogen
Decreased AT3
Presence of RBC fragments on blood smear