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Flashcards in Hematology II Deck (116)
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1
Q

The Right Lymphatic Duct and the Thoracic Duct drain into what veins?

A

Subclavians

2
Q

An increase in ____ or a decrease in ____ will lead to edema.

A

Pc

Pi-c

3
Q

When is the Thymus largest?
What does it produce?
Located?

A

Puberty

WBC - especially T-lymphocytes

Mediastinum

4
Q

Three sets of Tonsils:

A

Pharyngeal (adenoids)
Palatine
Lingual

5
Q

Where is the Mucosa Associated Lymphoid Tissue (MALT)?

A

Mucosal epithelium of the intestine

*B and T lymphocytes

6
Q

A defect in what will cause bleeding or thrombosis?

A

Hemostasis

7
Q

From whence do platelets come?

A

Megakaryocytes

8
Q

How many platelets can a single megakaryocyte produce?

A

3000

9
Q

What percentage of platelets are pooled in the spleen?

What is the normal level of platelets in the blood?

A

20-30%

250k - 400k / mm3

10
Q

T/F

Platelets contain granules

A

True

11
Q

What is the average lifespan of a platelet?

A

5-20 days

12
Q

What layer is different in veins?

A

Thinner tunica media

13
Q

What is the anatomy of a capillary?

A

Tunica Intima only
(no media or external)

Contains endothelial cells and small amount of collagen

14
Q

The body’s first reaction to injury is the ____ phase.

A

Vasoconstrictive

aka Vascular Spasm

15
Q

What is the vasoconstrictive phase triggered by?

A

Sympathetic system

direct injury itself

16
Q

What is the precursor to a blood clot?

A

Platelet plug

17
Q

What receptors on platelets bind collagen structure and form a plug?

A

GP1a

18
Q

Where is von Willebrand’s Factor found?

A

plasma
platelets
bv walls

19
Q

What binds to von Willebbrand’s Factor?

A

GP1b receptors

*on platelets

20
Q

First 2 steps of platelet plug formation:

A

GP1a attaches to exposed collagen

Gp1b attaches to von Willebrand’s Factor

21
Q

What are the 3 platelet granules released upon adhesion?

A

ADP
Thromboxane A2 (prostaglandin)
Serotonin (5-HT)

22
Q

What do ADP, TXA2, and 5-HT do once released from platelets?

A

Bind/recruit other platelets

Aggregate

23
Q

What platelet receptor is responsible for aggregation of the platelet plug?
What does it bind?

A

GPIIb

Fibrinogen

24
Q

Where are most clotting factors synthesized?

A

Liver

25
Q

Blood clotting factors I, II, III

A

Fibrinogen
Prothrombin
Tissue factor/thromboplastin

26
Q

Blood clotting factors IV, V, VII

A

Calcium
Proaccelerin (labile)
Proconvertin (stabile)

27
Q

Blood clotting factors VIII, IX, X

A

Antihemophilic factor A/globulin

Antihemophilic factor B, Plasma thromboplastin component, Christmas factor

Stuart-Prower factor

28
Q

Blood clotting factors XI, XII, XIII

A

Plasma thromboplastin antecedent, Hemophilia C, Rosenthal syndrome

Hageman factor

Fibrin stabilizing factor, Laki Lorand factor

29
Q

What blood clotting factors are not made in the liver?

4 factors

A

III - perivascular tissue
IV - Plasma
XII - Platelets (and liver)
XIII - Platelets, plasma

30
Q

What blood clotting factors are Vitamin K dependent?

4 factors

A

II - Prothrombin
VII - Proconvertin (stable)
IX - Ab, PTC, Xmas
X - Stuart-Prower

31
Q

Extrinsic clotting cascade:

A

III - thromboplastin
IV - Ca
VII - Proconvertin
V - Proaccelerin

X - Stuart Prower

32
Q

Intrinsic clotting cascade:

A

XII - Hageman
XI - Plasma thromboplastin antecedent
(aka Rosenthal, Hemophilia C)
IX - Plasma thromboplastin component
(aka Christmas, Anti-hemophilic factor B)
VIII - Anti-hemophilic factor A / Globulin

X - Stuart Prower

33
Q

Common clotting cascade:

A

X - Stuart Prower
III (thromboplastin), V (proaccelirin), IV (Ca), PF3
Prothrombin Activator
II - Prothrombin > Thrombin (feedback V - proaccelirin)
I - Fibrinogen > Fibrin >
XIII - Laki Lorand (Fibrin stabilizing), Ca >
Fibrin Polymer

34
Q

Name 3 Anti-coagulants that help to balance Hemostasis:

A

Thrombomodulin
Antithrombin III
Heparin cofactor II

35
Q

How does Thrombomodulin work to shut down the coagulation pathway?

A
Thrombomodulin-Thrombin Complex forms
activated
Protein C and Protein S
deactivates
V and VIII
36
Q

Which anti-coagulant is a glycoprotein produced by the liver that binds Factor X?

A

Antithrombin III

37
Q

What does Heparin cofactor II inhibit?

What type of protein is it and where is it synthesized?

A

Thrombin

Plasma

Liver

38
Q

What enzyme initiates the breakdown of a blood clot?

A

Plasmin

from Plasminogen

39
Q

What converts Plasminogen to active Plasmin?

and thus initiated Fibrinolysis

A

Tissue Plasminogen Activator (t-PA)

40
Q

What releases t-PA into the blood?

A

Damaged endothelium of vessels

41
Q

Where is the Plasminogen that degrades a clot found?

A

In the clot

42
Q

T/F

Plasminogen is fast acting

A

False

very slow to break down fibrin mesh

43
Q

What are 2 tPA inhibitors?

A

Plasminogen activator inhibitor 1

Plasminogen activator inhibitor 2

44
Q

What are 2 Plasmin inhibitors?

A

Alpha2-antiplasmin

Alpha2-macroglobulin

45
Q

What is a low platelet count?

from blood smear

A

Thrombocytopenia

46
Q

What can thrombocytopenia lead to?

4 things

A

Purpuria (purple spots)
Petechia (pinpoint hemorrhages)
nosebleeds
gum bleeds

47
Q

Some inherited platelet disorders are associated with…

A

large platelets

48
Q

What is the function of Sodium Citrate in coagulation tests?

A

Removes Calcium

49
Q

What is the coagulation test for the Extrinsic Pathway?
After Calcium, what is added?
How long before clotting occurs if normal?

A

Prothrombin Time (PT)

Brain Thromboplastin

12-15 seconds

50
Q

What standardizes differences in various companies coagulant factors used for testing?

What is the particular constant for a coagulant called?

A

International Normalized Ratio (INR)

ISI - international sensitivity index

51
Q

When is the INR normally used?

A

Warfarin (coumadin) usage

52
Q

What is the normal INR for someone using Warfarin?

A
  1. 0 - 3.0

* 2.5 - 3.5 if high risk for clot formation

53
Q

What tests the Intrinsic Pathway?

A

Activated Partial Thromboplastin Time (APTT)

54
Q

In the APTT test, what is activated after Calcium?

A

Kaolin

Phospholipids

55
Q

How long does clotting normally take in the APTT coagulation test?

A

25-36 seconds

56
Q

What is the APTT test most often used to monitor?

A

Heparin

57
Q

What tests the Common Pathway for coagulation time?

A

Thrombin Clotting Time (TT)

58
Q

After Calcium what is added to the Thrombin Clotting Time test?
(common pathway test)

A

Thrombin

*assesses Fibrinogen > Fibrin conversion

59
Q

When is the TT (Thrombin Clotting Time) test used?

A

If Prothrombin (extrinsic) or APTT (intrinsic) tests are prolonged

60
Q

What determines actual deficiencies for specific clotting disorders?

A

Coagulation Factor Assays

61
Q

If there is a prolongation of APTT test and PT is normal, what x-linked disorder might the patient have?

A

Hemophilia A or Hemophilia B

62
Q

What is the prevalence of Hemophilia A?

A

1 in 5000 males

63
Q

T/F

Hemophilia A is strictly genetically inherited

A

False

30% new mutations on VIII

64
Q

What is mutated in Hemophilia A?

A

VIII (antihemophilia factor A/globullin)

65
Q

What is mutated in Hemophilia B?
Another name?
prevalence?

A

IX
Christmas disease
1 in 30,000

66
Q

What are the 4 areas of most concern in hemophiliacs?

A

Joint capsules
Skeletal muscles
GI tract
Brain

67
Q

What process in joints caused hemophiliacs pain?

A

Healing

*breaks down bone

68
Q

What tests will be prolonged in Von Willebrand’s Disease?

A

APTT and PT

69
Q

Why will PT be prolonged in Von Willebrand’s disease if Factor VIII is the primary pathological concern?

A

Platelet adhesion is also disrupted

70
Q

What is the most common inherited bleeding disorder?

A

Von Willebrand’s Disease

125 per million

71
Q

T/F

Von Willebrand’s Disease is mild and occurs mainly in the skin

A

True

72
Q

What 2 pathologies are seen in Von Willebrand’s disease?

A

Platelet adhesion disrupted

Factor VIII

73
Q

What can disrupt production of platelets and cause Thrombocytopenia?

A

Drugs

marrow failure

74
Q

What can destroy platelets and cause Thrombocytopenia?

A

Idopathic thrombocytopenic purpura

*autoimmune

75
Q

What removes platelets in ITP - Idopathic thrombocytopenic purpura?

A

Reticuloendothelial system

76
Q

What conditions are associated with excessive clotting?

A

Thrombophilias

77
Q

What are 4 examples of Inherited Thrombophilias?

A

Protein C deficiency
Protein S deficiency
Activated Protein C Resistance
Antithrombin III deficiency

78
Q

What causes Activated Protein C resistance?

A

Factor V responds poorly to Protein C

*mutation in factor V Leiden gene

79
Q

What % of North American caucasians have a Factor V Leiden Mutation?

A

3-8%

80
Q

List the 4 inherited Thrombophilias in terms of prevalence?

A

Factor V Leiden
Protein C deficiency
Antithrombin deficiency
Protein S deficiency

81
Q

What are the 4 main categories of drugs affecting hemostasis?

A

Anticoagulants
Thrombolytics (destroy clots)
Antiplatelets
Antifibrinolytics (promote clots)

82
Q

What are the 4 main divisions of anticoagulant drugs?

A

Indirect thrombin inhibitors (Heparin)
Coumarin (Warfarin)
Direct Thrombin inhibitors
Direct Factor X inhibitors

83
Q

What are the 2 most common Heparins?

mixtures of proteins

A

Unfractionated heparin (UFH) - Heparin Sodium

Low molecular weight heparin (LMWH) - Fragmin, Innohep, Lovenox

84
Q

How is Heparin an indirect thrombin inhibitor?

A

Increases Antithrombin III’s activity, which shuts down factor X (Stuart-Power)

Stimulates Heparin cofactor II (also inhibits thrombin)

85
Q

T/F

UFH - unfractionated heparin can be given orally

A

False

Proteins are destroyed in stomach

86
Q

Why is UFH a variable anticoagulant?

A

Binds many proteins in body

*individually variable

87
Q

What test is used to monitor UFH?
What is normal?
By how much will theraputic levels of UFH prolong?

A

APTT
25-36 seconds
2-2.5 times normal values

88
Q

How are Low Molecular Weight Heparins administered?
What determines dose?
Does it need to be monitored?

A

Subcutaneously
Body weight
No

89
Q

How does Warfarin work?

A

Interferes with Vitamin K synthesis

90
Q

What factors are dependent on Vitamin K?

and therefore stopped by Warfarin

A

II
VII
IX
X

91
Q

T/F
Warfarin is used in prophylaxis of venous thrombosis, Pulmonary embolism, artificial heart valves, atrial fibrillation, surgery

A

True

92
Q

The INR - international normalized ratio for Warfarin is…

A

2.0 - 3.0

93
Q

What drugs inhibit Warfarin metabolism?

thus accumulating warfarin and increase effects

A

Cimetidine, acetaminophen, acute alcohol, antibiotics (azithromycin, cipro, clarithromycin, erythromycin)

94
Q

What hormone can increase catabolic breakdown of clotting factors and enhance the effects of Warfarin?

A

Thyroid hormones

95
Q

What drugs diminish effects of Warfarin?

A

Chronic alcohol
Phenytoin
Oral contraceptives

96
Q

What food decreases the effects of Warfarin?

A

Vitamin K

97
Q

T/F

Warfarin is fine during pregnancy, Heparin is not.

A

False

Warfarin is teratogenic - causes birth defects
Heparin is fine

98
Q

How are Direct Thrombin Inhibitors Administered?

What is the main DTI?

A

Orally

Dabigatran

99
Q

What are the advantages of Direct Thrombin Inhibitors?

A

non-reactive with blood proteins
Orally taken
No constant monitoring

100
Q

What are some Direct Factor X inhibitors?

A

Rivaroxaban
Apixaban
Endoxaban

101
Q

What type of drug is used in emergencies for Ischemic Strokes?

A

Thrombolytics

102
Q

How do Thrombolytics work?

A
tPA - tissue plasminogen activator
Forms Plamin (from Plasminogen) to break down clot
103
Q

Name 3 Thrombolytics:

A

Streptokinase
Urokinase
Synthetic tPA

104
Q

Name the 3 classes of Antiplatelets.

A

Cyclooxygenase Inhibitors (aspirin)
Thienopyridines (ADP inhibitors)
GP IIb/IIIa inhibitors

105
Q

How does Aspirin act as an anticoagulant?

A

Inhibits synthesis of TXA2

aggregating factor

106
Q

How do Thienopyridines (ADP inhibitors) work?

A

Prevent ADP - Platelet binding

prevents aggregation

107
Q

What is an ADP inhibitory drug?

(Thienopyridine)?

A

Clopidogrel

108
Q

What class of drugs inhibit the “final common pathway” for platelet aggregation?
Example of drug:
How administered?

A

Glycoprotein IIb/IIIa inhibitors
abciximab
I.V.

109
Q

What is an antifibrinolytic drug?

A

Tranexamic acid

110
Q

How is Tranexamic Acid used in dentistry?

A

5% mouth rinse in pts with prolonged bleeding times

111
Q

How does tranexamic acid work?

A

Prevents the formation of Plasmin by Plasminogen

(plasminogen inhibitor) by tPA

112
Q

What is the risk of developing thromboembolism if you stop taking Warfarin for 2 days?

A

0.02 to 1%

113
Q

T/F

It is safer to continue taking Warfarin throughout dental procedures and recovery.

A

False.

Safer to stop taking

114
Q

What is the recommended INR before dental surgery for patients on Warfarin?

A

Less than 4

115
Q

What solution is easier to make and less expensive than tranexemic acid?

A

Aminocaproic Acid

116
Q

T/F

Aminocaproic Acid isn’t available in Canada.

A

True

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