Hematology Flashcards
(151 cards)
1
Q
What is the function of thrombin?
A
Key to coagulation
Converts fibrinogen to fibrin
Activates factors V and VIII
Activates platelets
2
Q
What is the function of antithrombin III?
A
Key to anticoagulation
Binds and inhibits thrombin
Inhibits factors IX, X, and XI
Heparin activates antithrombin III
3
Q
What is the function of protein C?
A
Degrades factors V and VIII
Degrades fibrinogen
4
Q
What is the function of plasmin?
A
Degrades factors V and VIII, fibrinogen, and fibrin
5
Q
What factor has the shortest half life?
A
Factor VII
6
Q
What is the only factor not synthesized in the liver?
A
Factor VIII —synthesized in the endothelium with vWF
7
Q
The activity of what factors are lost in stored blood, but NOT FFP?
A
Factor V and VIII
8
Q
What factors are vitamin K dependent?
A
Factors II, VII, IX, X, protein C and S
9
Q
What works faster, PO or IV potassium?
A
PO. IV K+ takes 12 hours to take effect
10
Q
How long does it take FFP to work?
A
Immediately
11
Q
What is factor II?
A
Prothrombin
12
Q
What is the half life of RBC?
A
120 days
13
Q
What is the half life of platelets?
A
7 days
14
Q
What is the half life of PMNs?
A
1-2 days
15
Q
What is the function of prostacyclin (PGI2)?
A
From endothelium
Decreased platelet aggregation
Causes vasodilation
Increases cAMP in platelets
16
Q
What is the function of thromboxane?
A
From platelets
Increases platelet aggregation
Causes vasoconstriction
Triggers release of calcium in platelets —> exposes GpIIb/IIIa receptor to initiate platelet-platelet binding and platelet-collagen binding (GpIb)
17
Q
What product has the highest concentration of vWF-VIII?
A
Cryoprecipitate
18
Q
What product has high levels of fibrinogen?
A
Cryoprecipitate
19
Q
What product has the highest levels of all coagulation factors, protein C and S, and AT-III?
A
FFP
20
Q
What 2 things cause release of factor VIII and vWF from endothelium?
A
DDAVP and conjugated estrogen
21
Q
What lab is best to measure liver synthesis function?
A
Prothrombin time (PT)—measures factors II, V, VII, and X, fibrinogen
22
Q
What is the normal activated clotting time (ACT)?
A
150-200 sec for routine anticoagulation
23
Q
What is the goal ACT for cardiopulmonary bypass?
A
> 480 seconds
24
Q
At what INR is it a relative contraindication for performing surgical procedures?
A
> 1.5
25
At what INR is it a relative contraindication to central line placement, percutaneous needle biopsies, and eye surgery?
>1.3
26
What is the MCC of surgical bleeding?
Incomplete hemostasis
27
What is the MC congenital bleeding disorder?
Von Wilebrand’s disease
28
What is the MC symptom of vWF disease?
Epistaxis
29
What is the function of vWF?
Links GpIb receptor on platelets to collagen
30
What is the inheritance pattern of types I, II, and III VWF disease?
Types I and II are autosomal dominant
| Type III is autosomal recessive
31
What test is abnormal in vWF disease?
Ristocetin test = bleeding time
PT normal
PTT can be normal or abnormal
32
What is the dysfunction in type I vWF disease?
Reduced quantity of vWF
33
What is the treatment for type I vWF?
Recombinant VIII:vWF, DDAVP, cryoprecipitate
34
What is the dysfunction in type II vWF disease?
Defect in vWF molecule so it doesn’t work well
35
What is the treatment for type II vWF disease?
Recombinant VIII:vWF, DDAVP, cryoprecipitate
36
What is the dysfunction in type III vWF disease?
Complete vWF deficiency (rare)
37
What is the treatment for type III vWF disease?
Recombinant VIII:vWF , cryoprecipitate
| DDAVP will not work because there is no vWF to be released
38
What is hemophilia A?
Factor VIII deficiency
39
How is hemophilia A inherited?
Sex link recessive
40
What is the MC symptom of hemophilia A?
Hemarthrosis
41
If a patient has hemophilia A, what should the levels of factor VIII be pre-op and post-op?
Pre-op, need levels to be 100%
| Post-op, levels should be 80-100% for 10-14 days post-op
42
What test is abnormal in hemophilia A?
Prolonged PTT and normal PT
| Follow PTT Q8H after surgery
43
Which factor crosses the placenta?
Factor VIII—this is why newborns with hemophilia A may not bleed at circumcision
44
What should you do if patient with hemophilia A has joint bleeding?
DO NOT ASPIRATE
| Ice, keep joint mobile with range of motion exercises, factor VIII concentrate or cryoprecipitate
45
What should you do if patient with hemophilia A has epistaxis, intractable hemorrhage, or hematuria?
Recombinant factor VIII, cryoprecipitate
46
What is hemophilia B?
Factor IX deficiency. Also known as Christmas disease
47
How is hemophilia B inherited?
Sex-linked recessive
48
If a patient has hemophilia B, what should the levels be pre-op and post-op?
Need level 100% pre-op
| Must keep 30-40% for 2-3 days after surgery
49
What test is abnormal in hemophilia B?
Prolonged PTT and normal PT
50
What is the treatment for hemophilia B?
Recombinant factor IX or FFP
51
What labs are abnormal in factor VII deficiency?
Prolonged PT and normal PTT
52
Treatment for factor VII deficiency?
Recombinant factor VII or FFP
53
What signs are usually present in platelet disorders?
Bruising, epistaxis, petechiae, and purpura
54
What is Glanzmann’s thrombocytopenia?
GpIIb/IIIa receptor deficiency on platelets (usually links fibrin between platelets)
55
What is the treatment for Glanzmann’s thrombocytopenia?
Platelets
56
What is Bernard Soulier syndrome?
GpIb receptor deficiency on platelets —cant bind to collagen
57
What is the treatment for Bernard Soulier syndrome?
Platelets
58
What can cause acquired thrombocytopenia?
H2 blockers, heparin
59
How do we define uremia?
BUN > 60-80
60
What is the effect of uremia on hemostasis?
Inhibits platelet function by inhibiting release of vWF from endothelium
61
What is the treatment of bleeding due to uremia?
Hemodialysis-first line
DDAVP for acute reversal
Cryoprecipitate for moderate to severe bleeding
62
What causes heparin-induced thrombocytopenia (HIT)?
Thrombocytopenia due to anti-heparin antibodies (IgG heparin
63
What signs would you expect to see in a patient with HIT?
Platelets <100, a drop in platelets >50% of admission levels, thrombosis while on heparin
64
What kind of clot forms in HIT?
A white clot
65
How do you diagnose HIT?
ELISA for heparin Ab’s
| Serotonin release assay
66
What is the treatment for HIT?
Stop heparin, start argatroban (direct thrombin inhibitor) for anticoagulation
67
Should you give platelets in HIT?
NO! Increases the risk of thrombosis
68
What lab values would be abnormal in disseminated intravascular coagulation (DIC)?
Decreased platelets
Low fibrinogen
High fibrin split products (high D-dimer)
Prolonged PT and PTT
69
What often initiates DIC?
Tissue factor
70
What is the treatment for DIC?
Treat the underlying cause
71
How long before surgery should a patient stop taking ASA?
7 days before
72
What lab value will be abnormal in a patient taking ASA?
Bleeding time
73
MOA of ASA?
Inhibits cyclooxygenase in platelets and decreases TXA2 —> irreversibly inhibits COX.
Platelets have no DNA, so cannot resynthesize COX
74
How soon should a patient stop clopidogrel (Plavix) before surgery?
7 days before surgery
75
MOA of Plavix?
ADP receptor antagonist
76
If patient on Plavix is bleeding, what should you do?
Give platelets
77
How soon should Coumadin be stopped before surgery?
7 days before surgery. COnsider starting heparin while Coumadin wears off
78
If patient on Coumadin starts bleeding, what should you do?
Give vitamin K and FFP
79
What do you want platelet levels to be before surgery?
>50,000
80
What do you want platelet levels to be after surgery?
>20,000
81
During what surgery is urokinase released, causing thrombolysis?
Prostate surgery
82
What is a Amicar and what is it used for?
Aminocaproic acid. Inhibits fibrinolysis by inhibiting plasmin
83
Does no bleeding at circumcision rule out bleeding disorders?
No because can still have clotting factors from mother
84
What is the most common congenital hypercoagulability disorder?
Factor V Leiden mutation
85
What is factor V Leiden?
Defect on factor V that causes resistance to activated protein C
86
What is the treatment for factor V Leiden mutation?
Heparin, warfarin
87
What is the treatment for hyperhomocysteinemia?
Folic acid and vitamin B12
88
What is the prothrombin gene mutation?
G20210A
89
Treatment for prothrombin gene defect?
Heparin, warfarin
90
Treatment for protein C and S deficiency?
Heparin, warfarin
91
Does heparin work for patients with AT-III deficiency?
Heparin does not work in these patients
92
What can cause AT-III deficiency?
Exposure to heparin
93
What is the treatment for AT-III deficiency?
Recombinant AT-III concentrate or FFP (highest concentration of AT-III) followed by heparin then warfarin
94
What is the treatment for dysfibrinogenemia, dysplasminogenemia?
Heparin, warfarin
95
What causes polycythemia Vera?
Bone marrow overproduction
96
What do we worry about in patients with polycythemia Vera?
Thrombosis
97
What is the goal before surgery in patients with polycythemia Vera?
Keep Hct < 48 and platelets <400 before surgery
98
What is treatment for polycythemia Vera?
Phlebotomy, ASA, hydroxyurea
99
What are the symptoms of anti-phospholipid syndrome?
Thrombosis, loss of pregnancy
100
Do all patients with anti-phospholipid antibody syndrome have SLE?
NO
101
What causes anti-phospholipid antibody syndrome?
Antibodies to phospholipids including cardiolipin and lupus anticoagulant
102
What lab values are abnormal in anti-phospholipid antibody syndrome?
Prolonged PTT —> BUT STILL HYPERCOAGULABLE
103
How to diagnose anti-phospholipid antibody syndrome?
Prolonged PTT (not corrected with FFP)
Positive Russell viper venom time
False-positive RPR test for syphilis
104
Treatment for anti-phospholipid antibody syndrome?
Heparin, warfarin
105
What is the most common factor causing hypercoagulability?
Tobacco
106
Name acquired hypercoagulability syndromes?
Malignancy, inflammatory states, IBD, infections, oral contraceptives, pregnancy, RA, post-op patients, myeloproliferative disorders
107
When does warfarin-induced skin necrosis occur?
When placed on Coumadin without being heparinized first
108
What causes warfarin-induced skin necrosis?
Due to short half-life of proteins C and S, which are first to decrease in levels compared with the procoagulation factors —> results in hyperthrombotic state
109
What patients are especially susceptible to warfarin-induced skin necrosis?
Patients with protein C deficiency
110
What are the key elements in the development of venous thrombosis?
Virchow’s triad
111
What is Virchow’s triad?
Stasis, hypercoagulability, and endothelial injury
112
What is the key element for development of arterial thrombosis?
Endothelial injury
113
Why does a hypercoagulable state occur during cardiopulmonary bypass? How do we prevent it?
Due to factor XII (Haegman factor) activation. Give heparin to prevent
114
What is the treatment for DVT after first, second third one? PE?
First: warfarin for 6 months
Second: warfarin for 1 year
Third or significant PE: warfarin for life
115
What are the indications for IVC filter?
Contraindications to anticoagulation
PE while on anticoagulation
Free-floating IVC, Iloilo-femoral, or deep femoral DVT
Recent pulmonary embolectomy
116
Should IVC be placed above or below renal veins?
Below
117
What is the source if a patient has a PE with a filter in place?
SVC (upper extremity), IVC above the filter, or gonadal veins
118
If your clinical suspension for a PE is high, what should you do?
Do not wait for the CT scan, give heparin bolus, unless there is a contraindication
119
If patient with PE is in shock despite massive knot ropes and pressors, what should you do?
Go to the OR for open removal or angiography for suction catheter
120
What is the most common region where PEs come from?
Ilio-femoral region
121
In what instances is aminocaproic acid used?
Used in DIC, persistent bleeding following cardiopulmonary bypass, and thrombolytic overdoses
122
What is the MOA of warfarin?
Prevents vitamin K-dependent decarboxylation of glutamic residues on vitamin-K dependent factors
123
Name the 3 oral, direct thrombin inhibitors
Dabigatran (Pradaxa), apixaban (Eliquis), and rivaroxaban (Xarelto)
124
In what patients are oral direct thrombin inhibitors used?
Patients with a. Fib NOT due to heart valve problem and in patients with DVT or PE
125
How do sequential compression devices help prevent DVT?
Improve venous return and induces fibrinolysis with compression (release of tPA from endothelium)
126
How does heparin work?
Binds and activates ATIII (1000x more activity) and increased neutralization of factors IIa and Xa
127
What is used to reverse effects of heparin?
Protamine (binds directly to heparin)
128
What is the half life of heparin?
60-90 minutes
129
What is the goal PTT when a patient is on heparin?
60-90 seconds
130
What are some long-term side effects of heparin?
Osteoporosis, alopecia
131
How is heparin cleared?
By the reticuloendothelail system (spleen, macrophages)
132
Which anticoagulant can be used during pregnancy, warfarin or heparin?
Heparin because it does not cross the placental barrier. Warfarin does cross placental barrier
133
What do we worry about when giving protamine?
Cross reaction with NPH insulin or previous protamine exposure
In 1% of patient, they get protamine reaction (hypotension, bradycardia, and decreased heart function)
134
What is the difference between low molecular weight heparin (enoxaparin) and unfractionated heparin?
Low molecular weight heparin has a lower risk of HIT and binds to antithrombin III but increased neutralization of JUST factor Xa —> not reversed with protamine
135
What is argatroban?
Reversible direct thrombin inhibitor
136
Where is argatroban metabolized?
In the liver
137
What is the half-life of argatroban?
50 minutes
138
When is argatroban often used?
In patients with HIT
139
What is bivalirudin?
Reversible direct thrombin inhibitor
| Also known as angiomax
140
How is bivalirudin metabolized?
By proteinase enzymes in the blood
141
What is the half life of bivalirudin?
25 minutes
142
What is Hirudin?
Irreversible direct thrombin inhibitor
143
Where is hirudin derived from?
Leeches
144
WHat isn’t eh most potent direct inhibitor of thrombin?
Hirudin
145
What is Ancrod?
Malayan pit viper venom that stimulates tPA release
146
What are the 3 MC thrombolytics?
TPA, streptokinase, and urokinase
147
How do thrombolytics work?
Activate plasminogen
148
How do you follow effects fo thrombolytics?
Follow fibrinogen levels
| Fibrinogen leaves <100 is associated with increased risk and severity of bleeding
149
What are absolute contraindications to thrombolytics?
Active internal bleeding
Recent CVA or neurosurgery (<3 months)
Intracranial pathology
Recent GI bleeding
150
What are major contraindications to thrombolytic use?
Recent surgery (<10 days), organ biopsy, or obstetric delivery, left heart thrombus, active peptic ulcer, recent major trauma, uncontrolled HTN, recent eye surgery
151
What are minor contraindications to thrombolytic use?
Minor surgery, recent CPR, atrial fibrillation with mitral valve disease, bacterial endocarditis, hemostasis defects (renal or liver disease), diabetic hemorrhagic retinopathy, pregnancy
