Secondary Hemostasis Flashcards

1
Q

Requirements of ACT coagulation test

A

Whole Blood

Contact Activator

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

Significance of prolonged Thrombin Time

A

Quantitative or qualitative abnormalities of fibrinogen

Inhibitors of fibrin formation

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

_______________ is required for the initation of secondary hemostasis when initiated by wounds

A

Tissue Factor

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

Result of Disseminated Intravascular Coagulation (DIC)

A

Thrombosis of the microvasculature

Depletion of coagulation factors and platelets → bleeding

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

Significance of prolonged PT

A

Factor VII deficiency

Deficiency or inhibition of common pathway factor

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

Inhibitor Consumption Tests

A

Antithrombin (AT)

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

Requirements for PT coagulation test

A

Citrated plasma

Tissue factor

Calcium

Platelet substitute

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

Cause of Disseminated Intravascular Coagulation (DIC)

A

Continued activation of coagulation and fibrinolysis

Induction or exposure of tissue factor or other activators of coagulation

Endothelial damage exposing collagen

Proteolytic enzymes

Stagnant blood flow

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

Increased concentration of D-Dimers occurs wtih

A

Increased fibrinolysis

Severe internal hemorrhage with fibrinolysis

Decreased clearance of FDP by liver

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

Coagulation test for the common pathway

A

Fibrinogen

TT

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

Tissue Factor Pathway Inhibitor inhibits

A

Generation of Xa

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

Loads of thrombin generated on the platelet surface drives the formation of

A

Fibrin

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

Thromibin time measures

A

Time for fibrin clot formation in citrated plasma + thrombin

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

Inhibitors of coagulation

A

Antithrombin

Activated Protein C (APC)

Tissue Factor Pathway Inhibitor (TFPI)

Alpha-2 Macroglobulin

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

Significance of fibrinogen concentration increase

A

Inflammation

Relative increase with dehydration

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

Two phases of DIC

A

Hypercoagulabile Phase

Consumptive Phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Steps of the Common Pathway of the Coagulation Cascade

A
  1. X → Xa
  2. Prothrombin → Thrombin by Xa
  3. Fibrinogen → Fibrin by Thrombin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Vitamin K dependent Factors?

A

II, VII, IX, X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Categories of coagulation tests

A

Procoagulant Tests

Anticoagulat Tests

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

PIVKA would be increased in

A

Vitamin k antagonism/deficiency

Human hepatocellular carcinomas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Hypercoagulable Phase of DIC

A

Thrombosis

Ischemic necrosis and organ dysfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Prothrombin Time (PT) measures

A

Time for fibrin clot formation in citrated plasma + tissue factor + calcium + platelet phospholipid substitute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Clinical signs of DIC

A

Associated with the signs of primary disease

Signs of organ dysfunction secondary to thrombosis

Bleeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Requirements of aPTT coagulation test

A

Citrated Plasma

Contact activator

Calcium

Platelet substitute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Plasmin degrades fibrin into

A

Fibrin Degradation Products

D- Dimers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Pathogenesis of the hypercoagulable phase of DIC leading to organ dysfuction

A

Thrombus formation → blockage of the microvasculature → Ischemic necosis → Organ dysfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Hemophilia B

A

Factor IX deficiency

Dogs and Cats

Signs and inheritance patterns similar to Hemophilia A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Requirements for Thrombin Time coagulation test

A

Citrated plasma

Thrombin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Mechanism of action of Antithrombin

A
  1. Heparin binds to antithrombin
  2. Heparin causes conformational change and exposes the thrombin binding site
  3. Thrombin binds to AT = TAT complex and heparin floats away
  4. Tat Comples is cleared by the phagocytic system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Secondary Hemostasis

A

Stabilization of the platelet plug via fibrin meshwork - used in large defects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Laboratory findings in Warfarin Toxicity

A

PT - prolonged

aPTT, ACT - prolonged

PIVKA - positive

Platelet count - normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Three phases of the cell-based model

A

Initiation

Amplification

Propagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Why does vitamin k antagonism work?

A

Vitamin K dependent factors los their negative charge and are not recruited to sites of injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Hageman’s Disease

A

Factor XII deficiency

Cats and Killer Whales

Deficiency not associated with bleeding - prolonged PTT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Secondary hemostasis occurs on

A

Platelet surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Fibrin Degradation Products inhibit

A

Platelet function and fibrin polymerization

37
Q

Which of the intrinsic pathway coagulation tests is more sensitive?

A

aPTT

38
Q

Laboratory findings of hemophilia A

A

Platelet Count - Normal

Bleeding Time - Normal

aPTT and ACT - Prolonged

PT- normal

Factor activity - reduced

39
Q

Pathophysiology of Warfarin Toxicity

A

Coumarins block enzymes required to reduce vitamin K

Negative charge not transferred to coagulation factors

Platelet surface charge remains positive

Factors X and II unable to bind to platelet

40
Q

Coagulation factors are synthesized in the

A

Liver

41
Q

Treatment of warfarin toxicosis

A

Decontamination

Supplement vitamin K

Plasma and/or blood transfusions

42
Q

Fibrinolytic Activity Tests

A

Fibrin Degradation Products

D-Dimer

43
Q

How is citrated plasma different than blood?

A

No RBC, WBC or Platelets

Decreased Calcium

44
Q

Key factor that promotes amplification of secondary hemostasis

A

Thrombin

45
Q

For collection of blood for coagulation tests, what tube should be used?

A

Blue Top - Citrate Tube

46
Q

Factors involved in the Intrinisc Pathway

A

XII, XI, IX, VIII

47
Q

X is converted to Xa by what in the Intrinisc Pathway?

A

IXa

48
Q

Activated Protein C inhibits

A

Va, VIIa

49
Q

Coagulation test for the intrinsic pathway

A

aPTT

ACT

50
Q

aPTT and ACT tests measure

A

Time for fibrin clot formation

51
Q

Factors involved in the Extrinsic Pathway

A

Tissue Factor III

VII

52
Q

Pathways that make up the coagulation cascade

A

Intrinsic pathway - Contact Activation

Extrinsic pathway - Tissue Activation

Common Pathway

53
Q

Clinical features of Warfarin Toxicosis

A

Bleeding - Anemia, weakness, pallor, hypovolemia, shock, dyspnea, lameness, neurologic signs

Death

54
Q

What is the cardinal bloodwork finding for a patient in consuptive phase of DIC?

A

Thrombocytopenia

55
Q

Significance in fibrinogen concentration decrease

A

Consumption due to hypercoagulation - excessive conversion of fibrinogen to fibrin

Decreased production by the liver

56
Q

Pathogenesis of hypercoagulable phase of DIC leading to bleeding

A

Thrombus formation → fibrinolysis → increased FDPs → decreased platelet function → bleeding

57
Q

Significance of prolonged aPTT and ACT time

A

Deficiency or inhibition of any intrinsic or common pathway factor

Heparin therapy

58
Q

IX is converted to IXa in the Intrinsic Pathway by

A

VIIa

59
Q

Coagulopathy and Liver disease

A

Decreased synthesis of coagulation factors

Production of dysfunctional factors

60
Q

X is converted to Xa by what in the Extrinisic Pathway

A

VIIa

61
Q

Treatment for DIC

A

Identify and eliminate underlying disorder

Fluid therapy

Transfusion therapy

62
Q

Hemophilia A

A

Factor VIII deficiency

X linked recessive inheritance

Causes mild, moderate or severe bleeding

63
Q

Non-Enzymatic factors of the coagulation cascade

A

Tissue Factor (Factor III, Thromboplastin)

Factor VIIIa

Factor Va

Calcium

Platelets

64
Q

Factors affected by amplification

A

XI

VII

VIIIa

Va

65
Q

Coagulation Tests

A

Activated Partial Thromboplastin Time (aPTT, PTT)

Prothrombin Time (PT)

Thrombin Time (TT), Fibrinogen

PIVKA

Special Factor Assay

66
Q

PIVKA

A

Proteins induced by vitamin K antagonism

Indirectly measures abnormal forms of vitamin K dependent factors

67
Q

Increased concentration of fibrin degradation products occus when

A

Increased fibrinolysis

Severe internal hemorrhage with fibrinolysis

Decreased clearance of FDP by liver

68
Q

Antithrombin inhibits

A

Thrombin, IXa, Xa

69
Q

VII is converted to VIIa in the extrinsic pathway by

A

Xa

70
Q

Fibrinogen is an indicator of what in large animals

A

Inflammation

71
Q

Laboratory findings of DIC

A

Thrombocytopenia

PT, aPTT - Prolonged

Fibrinogen - decreased

FDP and D-Dimers - increased

Antithrombin - decreased

Hemorrhagic anemia

Schistocytes

72
Q

aPTT requires ______% deficiency before prolongation is detected

A

70%

73
Q

ACT requires ______% deficiency of factor before prolongation is detected

A

95%

74
Q

Serum biochemistries for DIC depend on

A

Primary Disease

Location of microthrombosis

75
Q

PT requires ______% deficiency of factor before prolongation is detected

A

70%

76
Q

Alpha-2 Macroglobulin inhibits

A

Thrombin

Plasmin

Kallikrein

77
Q

Prothrombin is converted to Thrombin by

A

Xa

78
Q

Enzymatic Factors of the Coagulation Cascade

A

XII, XI, IX, VII, X

Prothrombin

Thrombin

Fibrinogen

Fibrin

79
Q

Pathogenesis of consumptive phase of DIC

A

Depletion of coagulation factors and platelets → bleeding

80
Q

Fibrinogen is converted to Fibrin by

A

Thrombin

81
Q

Activated Clotting Time ACT measures

A

Time for fibrin clot formation in non-anticoagulated whole blood

82
Q

Coagulation test for the extrinsic pathway

A

PT

83
Q

Plasminogen is converted to Plasmin by

A

Tissue Plasminogen Activator (TPA)

84
Q

Inherited Factor Deficiencies

A

Hemophilia A - VIII

Hemophilia B - IX

Hagemans Disease - XII

85
Q

Factors involved in the common pathway

A

X, V

Prothrombin

Fibrinogen

Fibrin

86
Q

Cell Based Model

A

Focuses on the roll of cells involved with coagulation

87
Q

Why is PT a good choice in test for screening for Vitamin K deficiency?

A

Because Factor VII has the shortest half life

88
Q

Causes of Warfarin Toxicosis

A

Poisoning with coumarin derivatives

Fat malabsorption

Dietary deficiency

Antibiotics that cause decreased absorption or utilization by liver

89
Q

It is good practice to supplement a patient with prolonged aPTT with what before surgery?

A

Plasma