Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Phase 1 > Chapter 7 Bleeding and Hemostasis > Flashcards

Chapter 7 Bleeding and Hemostasis Flashcards

1
Q

What are platelets roles in primary hemostasis

A
  1. Platelet adhesion
  2. Shape change
  3. Granule release of TXA2 and ADP
  4. Recruitment
  5. Aggregation (platelet plug)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe platelet adhesion

A

Platelets adhere to subendothelial collagen via platelet glycoprotein VI or vWF via glycoprotein Ib receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What triggers shape change during primary hemostasis

A

Adherence of platelets to subendothelial collagen and/or vWF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is released during activation in primary hemostasis

A

Secondary agonists - TXA2 and ADP via arachidonic acid metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which coagulation test most closely reflects in vivo hemostasis?

A

TEG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

D-dimer

A

Indicates activation of thrombin and plasmin and are specific for active coagulation and fibrinolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which tests evaluate the intrinsic pathway

A

APTT - if prolonged then defective intrinsic or common pathway
ACT - less sensitive but also evaluates both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which test evaluates the extrinsic pathway?

A

PT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which test is most sensitive to vitamin K deficiency

A

PT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the three phases of coagulation

A

Initiation
Amplification
Propagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is generated in the initiation phase

A

Thrombin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What occurs during amplification phase

A

thrombin amplifies signal and sets stage for procoagulant complex assembly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What occurs during propagation?

A

Complexes assemble on the surface of activated platelets and large amounts of thrombin and fibrin are generated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the product of Initiation

A

thrombin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Factors involved in amplification

A

Plt activated by thrombin produced in initiation phase
PLT are activated and have activated cofactors V and VIII

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Factors involved in propagation

A

fXI activated by thrombin —> fXIa
fXIa generates fIXa
[fIXa + tissue factor bearing cells + fVIIIa] = activates fX —> fXa
Common pathway: [fXa + fVa] activate prothrombin into thrombin to cleave fibrinogen into large amounts of fibrin

17
Q

What are three natural anticoagulants

A

Antithrombin
Protein C
Tissue factor inhibitor

18
Q

Natural anticoagulant - Antithrombin moa

A

Circulating alpha-globulin* produced in the liver
Binds and inactivates thrombin fIXa, fXa, fXIa, and fXIIa *

19
Q

Natural anticoagulant - Protein C (and cofactor S) moa

A

Inactivate cofactors fVa and fVIIIa and slows thrombin formation

20
Q

Natural coagulant - Tissue factor inhibitor moa

A

Binds and inactivates FXa and fVIIa-tissue factor
Antiangiogenic and antimetastatic properties

21
Q

What type of von willebrands disease would benefit from desmopressin

A

Type I

22
Q

vWF effects of DAVPP

A

Desmopressin can be used as adjunctive therapy in dogs with type 1 vWD during bleeding crisis or can be prophylactically given 30 min before surgery. Usually maximal response achieved 1-2 hours after dosing.
Response: increased [vWF] and factor VIII and shortened bleeding times likely from release of vWF and factor VIII from endothelial stores
Also works in dogs on aspirin

23
Q

vWD ELISA

A

Definitive diagnosis of vWD requires determination of vWF levels via ELISA.
< 50% is considered deficient. Differentiation between type 1 and 2 requires determination of multimer distribution via immunoelectrophoresis

24
Q

vWF role

A

Serves as an adhesion bridge between subendothelial collagen and glycoprotein Ib platelet receptor

Adherence to glycoprotein Ib platelet receptor triggers shape change, stimulation of arachidonic acid metabolism, and release of granular contents (activation)

25
Q

What blood product is given to patients with vWD prior to surgery and how long does it last?

A

Cryoprecipitate
Concentration elevated within 30 minutes and remains elevated for 4 hours.

26
Q

What factors are in cryoprecipitate?

A

Factor VIII, vWF, fibronectin, and fibrinogen

27
Q

Plavix MOA

A

ADP antagonist: active metabolites irreversibly block ADP from binding to its receptor on the PLT (PY2) preventing activation of alpha IIb Beta 3 intern, fibrinogen binding, and aggregation

28
Q

How long does it take for platelet inhibition when giving plavix?

A

Inhibition occurs in 2-5 days

29
Q

How long prior to surgery should plavix be discontinued?

A

7-10 days

30
Q

Describe bleeding in greyhounds or sight hounds

A

1/3 of clinically normal greyhounds may develop delayed bleeding up to 3 days after elective surgery due to altered fibrinolysis

31
Q

Why are dogs with HAC (Cushing’s) susceptible to thromboembolic events?

A

COX-2 inhibition by endogenous glucocorticoids may cause increase risk of thrombogenesis in dogs with HAC

32
Q

Which tests are for primary vs secondary hemostatis

A

Primary - BMBT and platelet count
Secondary - ACT, PT, PTT

Phase 1 (71 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions