Hematology II Flashcards
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
Blood clotting factors I, II, III
Fibrinogen
Prothrombin
Tissue factor/thromboplastin
26
Blood clotting factors IV, V, VII
Calcium
Proaccelerin (labile)
Proconvertin (stabile)
27
Blood clotting factors VIII, IX, X
Antihemophilic factor A/globulin
Antihemophilic factor B, Plasma thromboplastin component, Christmas factor
Stuart-Prower factor
28
Blood clotting factors XI, XII, XIII
Plasma thromboplastin antecedent, Hemophilia C, Rosenthal syndrome
Hageman factor
Fibrin stabilizing factor, Laki Lorand factor
29
What blood clotting factors are not made in the liver?
| 4 factors
III - perivascular tissue
IV - Plasma
XII - Platelets (and liver)
XIII - Platelets, plasma
30
What blood clotting factors are Vitamin K dependent?
| 4 factors
II - Prothrombin
VII - Proconvertin (stable)
IX - Ab, PTC, Xmas
X - Stuart-Prower
31
Extrinsic clotting cascade:
III - thromboplastin
IV - Ca
VII - Proconvertin
V - Proaccelerin
X - Stuart Prower
32
Intrinsic clotting cascade:
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
Common clotting cascade:
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
Name 3 Anti-coagulants that help to balance Hemostasis:
Thrombomodulin
Antithrombin III
Heparin cofactor II
35
How does Thrombomodulin work to shut down the coagulation pathway?
```
Thrombomodulin-Thrombin Complex forms
activated
Protein C and Protein S
deactivates
V and VIII
```
36
Which anti-coagulant is a glycoprotein produced by the liver that binds Factor X?
Antithrombin III
37
What does Heparin cofactor II inhibit?
| What type of protein is it and where is it synthesized?
Thrombin
Plasma
Liver
38
What enzyme initiates the breakdown of a blood clot?
Plasmin
| from Plasminogen
39
What converts Plasminogen to active Plasmin?
| and thus initiated Fibrinolysis
Tissue Plasminogen Activator (t-PA)
40
What releases t-PA into the blood?
Damaged endothelium of vessels
41
Where is the Plasminogen that degrades a clot found?
In the clot
42
T/F
| Plasminogen is fast acting
False
very slow to break down fibrin mesh
43
What are 2 tPA inhibitors?
Plasminogen activator inhibitor 1
| Plasminogen activator inhibitor 2
44
What are 2 Plasmin inhibitors?
Alpha2-antiplasmin
| Alpha2-macroglobulin
45
What is a low platelet count?
| from blood smear
Thrombocytopenia
46
What can thrombocytopenia lead to?
| 4 things
Purpuria (purple spots)
Petechia (pinpoint hemorrhages)
nosebleeds
gum bleeds
47
Some inherited platelet disorders are associated with...
large platelets
48
What is the function of Sodium Citrate in coagulation tests?
Removes Calcium
49
What is the coagulation test for the Extrinsic Pathway?
After Calcium, what is added?
How long before clotting occurs if normal?
Prothrombin Time (PT)
Brain Thromboplastin
12-15 seconds
50
What standardizes differences in various companies coagulant factors used for testing?
What is the particular constant for a coagulant called?
International Normalized Ratio (INR)
ISI - international sensitivity index
51
When is the INR normally used?
Warfarin (coumadin) usage
52
What is the normal INR for someone using Warfarin?
2. 0 - 3.0
| * 2.5 - 3.5 if high risk for clot formation
53
What tests the Intrinsic Pathway?
Activated Partial Thromboplastin Time (APTT)
54
In the APTT test, what is activated after Calcium?
Kaolin
| Phospholipids
55
How long does clotting normally take in the APTT coagulation test?
25-36 seconds
56
What is the APTT test most often used to monitor?
Heparin
57
What tests the Common Pathway for coagulation time?
Thrombin Clotting Time (TT)
58
After Calcium what is added to the Thrombin Clotting Time test?
(common pathway test)
Thrombin
*assesses Fibrinogen > Fibrin conversion
59
When is the TT (Thrombin Clotting Time) test used?
If Prothrombin (extrinsic) or APTT (intrinsic) tests are prolonged
60
What determines actual deficiencies for specific clotting disorders?
Coagulation Factor Assays
61
If there is a prolongation of APTT test and PT is normal, what x-linked disorder might the patient have?
Hemophilia A or Hemophilia B
62
What is the prevalence of Hemophilia A?
1 in 5000 males
63
T/F
| Hemophilia A is strictly genetically inherited
False
30% new mutations on VIII
64
What is mutated in Hemophilia A?
VIII (antihemophilia factor A/globullin)
65
What is mutated in Hemophilia B?
Another name?
prevalence?
IX
Christmas disease
1 in 30,000
66
What are the 4 areas of most concern in hemophiliacs?
Joint capsules
Skeletal muscles
GI tract
Brain
67
What process in joints caused hemophiliacs pain?
Healing
*breaks down bone
68
What tests will be prolonged in Von Willebrand's Disease?
APTT and PT
69
Why will PT be prolonged in Von Willebrand's disease if Factor VIII is the primary pathological concern?
Platelet adhesion is also disrupted
70
What is the most common inherited bleeding disorder?
Von Willebrand's Disease
| 125 per million
71
T/F
| Von Willebrand's Disease is mild and occurs mainly in the skin
True
72
What 2 pathologies are seen in Von Willebrand's disease?
Platelet adhesion disrupted
| Factor VIII
73
What can disrupt production of platelets and cause Thrombocytopenia?
Drugs
| marrow failure
74
What can destroy platelets and cause Thrombocytopenia?
Idopathic thrombocytopenic purpura
*autoimmune
75
What removes platelets in ITP - Idopathic thrombocytopenic purpura?
Reticuloendothelial system
76
What conditions are associated with excessive clotting?
Thrombophilias
77
What are 4 examples of Inherited Thrombophilias?
Protein C deficiency
Protein S deficiency
Activated Protein C Resistance
Antithrombin III deficiency
78
What causes Activated Protein C resistance?
Factor V responds poorly to Protein C
*mutation in factor V Leiden gene
79
What % of North American caucasians have a Factor V Leiden Mutation?
3-8%
80
List the 4 inherited Thrombophilias in terms of prevalence?
Factor V Leiden
Protein C deficiency
Antithrombin deficiency
Protein S deficiency
81
What are the 4 main categories of drugs affecting hemostasis?
Anticoagulants
Thrombolytics (destroy clots)
Antiplatelets
Antifibrinolytics (promote clots)
82
What are the 4 main divisions of anticoagulant drugs?
Indirect thrombin inhibitors (Heparin)
Coumarin (Warfarin)
Direct Thrombin inhibitors
Direct Factor X inhibitors
83
What are the 2 most common Heparins?
| mixtures of proteins
Unfractionated heparin (UFH) - Heparin Sodium
Low molecular weight heparin (LMWH) - Fragmin, Innohep, Lovenox
84
How is Heparin an indirect thrombin inhibitor?
Increases Antithrombin III's activity, which shuts down factor X (Stuart-Power)
Stimulates Heparin cofactor II (also inhibits thrombin)
85
T/F
| UFH - unfractionated heparin can be given orally
False
Proteins are destroyed in stomach
86
Why is UFH a variable anticoagulant?
Binds many proteins in body
*individually variable
87
What test is used to monitor UFH?
What is normal?
By how much will theraputic levels of UFH prolong?
APTT
25-36 seconds
2-2.5 times normal values
88
How are Low Molecular Weight Heparins administered?
What determines dose?
Does it need to be monitored?
Subcutaneously
Body weight
No
89
How does Warfarin work?
Interferes with Vitamin K synthesis
90
What factors are dependent on Vitamin K?
| and therefore stopped by Warfarin
II
VII
IX
X
91
T/F
Warfarin is used in prophylaxis of venous thrombosis, Pulmonary embolism, artificial heart valves, atrial fibrillation, surgery
True
92
The INR - international normalized ratio for Warfarin is...
2.0 - 3.0
93
What drugs inhibit Warfarin metabolism?
| thus accumulating warfarin and increase effects
Cimetidine, acetaminophen, acute alcohol, antibiotics (azithromycin, cipro, clarithromycin, erythromycin)
94
What hormone can increase catabolic breakdown of clotting factors and enhance the effects of Warfarin?
Thyroid hormones
95
What drugs diminish effects of Warfarin?
Chronic alcohol
Phenytoin
Oral contraceptives
96
What food decreases the effects of Warfarin?
Vitamin K
97
T/F
| Warfarin is fine during pregnancy, Heparin is not.
False
Warfarin is teratogenic - causes birth defects
Heparin is fine
98
How are Direct Thrombin Inhibitors Administered?
| What is the main DTI?
Orally
| Dabigatran
99
What are the advantages of Direct Thrombin Inhibitors?
non-reactive with blood proteins
Orally taken
No constant monitoring
100
What are some Direct Factor X inhibitors?
Rivaroxaban
Apixaban
Endoxaban
101
What type of drug is used in emergencies for Ischemic Strokes?
Thrombolytics
102
How do Thrombolytics work?
```
tPA - tissue plasminogen activator
Forms Plamin (from Plasminogen) to break down clot
```
103
Name 3 Thrombolytics:
Streptokinase
Urokinase
Synthetic tPA
104
Name the 3 classes of Antiplatelets.
Cyclooxygenase Inhibitors (aspirin)
Thienopyridines (ADP inhibitors)
GP IIb/IIIa inhibitors
105
How does Aspirin act as an anticoagulant?
Inhibits synthesis of TXA2
| aggregating factor
106
How do Thienopyridines (ADP inhibitors) work?
Prevent ADP - Platelet binding
| prevents aggregation
107
What is an ADP inhibitory drug?
| (Thienopyridine)?
Clopidogrel
108
What class of drugs inhibit the "final common pathway" for platelet aggregation?
Example of drug:
How administered?
Glycoprotein IIb/IIIa inhibitors
abciximab
I.V.
109
What is an antifibrinolytic drug?
Tranexamic acid
110
How is Tranexamic Acid used in dentistry?
5% mouth rinse in pts with prolonged bleeding times
111
How does tranexamic acid work?
Prevents the formation of Plasmin by Plasminogen
| (plasminogen inhibitor) by tPA
112
What is the risk of developing thromboembolism if you stop taking Warfarin for 2 days?
0.02 to 1%
113
T/F
| It is safer to continue taking Warfarin throughout dental procedures and recovery.
False.
Safer to stop taking
114
What is the recommended INR before dental surgery for patients on Warfarin?
Less than 4
115
What solution is easier to make and less expensive than tranexemic acid?
Aminocaproic Acid
116
T/F
| Aminocaproic Acid isn't available in Canada.
True
