Hemostasis Flashcards
1
Q
steps in hemostasis
A
1) blood vessels constrict to slow blood flow
2) platelets aggregate and stick to injured area and to each other
3) coag factors reinforce platelet plug with fibrin clot
4) removal of excess hemostatic material re-establishes integrity
2
Q
function of vascular system in hemostasis
A
vasoconstriction, diversion of blood flow, initiate contact with platelets and coag proteins
3
Q
function of platelets in hemostasis
A
formation of platelet plug to stop initial bleeding
4
Q
what stabilizes platelet plug
A
fibrin formation and thromboplastin
5
Q
fibrinogen group of coagulation factors
A
I
V
VIII
XIII
6
Q
prothrombin group of coagulation factors
A
II
VII
IX
X
7
Q
vitamin K dependent coagulation factors
A
II
VII
IX
X
8
Q
fibrinogen is factor ___
A
I
9
Q
prothrombin is factor ___
A
II
10
Q
tissue thromboplastin/tissue factor is factor ___
A
III
11
Q
ionic calcium is factor ___
A
IV
12
Q
labile factor/proaccelerin is factor ___
A
V
13
Q
stable factor (procovertin) is factor ___
A
VII
14
Q
antihemophilic factor/von Willebrand factor is factor ___
A
VIII
15
Q
Christmas factor/plasma thromboplastin factor ___
A
IX
16
Q
Stuart-Prower factor ___
A
X
17
Q
plasma thromboplastin antecedent is factor ___
A
XI
18
Q
Hageman factor/contact factor ___
A
XII
19
Q
fibrin stabilizing factor ___
A
XIII
20
Q
product recommended for increased LY30
A
antifibrinolytic (TXA)
21
Q
product recommended for decreased MA
A
platelet
22
Q
product recommended for decreased angle and increased K
A
cryo
23
Q
product recommended for increased R
A
FFP
24
Q
symptoms of vitamin K deficiency
A
easy bruising oozing from nose or gums excessive bleeding heavy periods bleeding from GI tract blood in urine/stool
25
coag test that measures time it takes for plasma to clot once thromboplastin and calcium are added
prothrombin time
26
PT measures what pathway?
extrinsic and common
27
coag test used to monitor warfarin therapy
PT
28
conditions with prolonged PT
```
warfarin therapy
vitamin K deficiency
liver disease
acquired or hereditary factor deficiency
factor inhibitor drugs or antibodies
```
29
coag test that measures times it takes for plasma to clot once activator reagent is added
activated partial thromboplastin time
30
PTT measures deficiencies in what pathway
intrinsic and common
31
PT reference range
11-13.5 seconds
32
PTT reference range
30-40 seconds
33
coag test used to monitor heparin therapy
PTT
34
conditions with prolonged PTT
heparin therapy
circulating inhibitors
decreases in circulating levels of II, IX, X in patients on oral anticoagulants
35
precursor to fibrin which is necessary for clot formation
fibrinogen/factor I
36
enzyme that converts fibrinogen to fibrin
thrombin
37
normal fibrinogen level
200-400 mg/dl
38
how is fibrinogen level measured
excess thrombin added to plasma and clotting time measured
| clotting time inversely proportional to fibrinogen concentration
39
test that measures conversion of fibrinogen to fibrin
thrombin time
40
normal thrombin time
15-25 seconds
41
reasons for prolonged thrombin time
low fibrinogen
impaired fibrinogen function
thrombin inhibitors
multiple myeloma
42
test to aid in determining cause of abnormal/prolonged PT or PTT results in which normal fresh plasma is mixed 1:1 with patient plasma
mixing study
43
if PT/PTT is corrected in a mixing study, the prolong is due to ___
factor deficiency
44
is PT/PTT is not corrected in a mixing study the prolong is due to ___
potential factor inhibitor
45
detects how well platelets stick together
Platelet (Ristocetin) aggregation
46
abnormal ristocetin aggregation due to:
```
meds that affect platelet function
von Willebrand disease
liver disease
acute leukemia
food consumption (caffeine, garlic, ginger)
```
47
test to aid in determining cause of abnormal PT/PTT where patient's plasma is tested with specific factor deficient substrate plasma
factor assay
48
factors tested using PT methodology when doing factor assays
II
V
X
49
factors tested using PTT methodology when doing factor assays
VIII
IX
XI
XII
50
test that screens for factor XIII deficiency
5M urea lysis (urea solubility)
51
physiology of 5M urea test
```
factor XIII crosslinks fibrin to stabilize clot
weak clot (fibrin not crosslinked) = clot dissolves
normal clots = do not dissolve
```
52
steps in fibrinolysis
plasminogen --> plasmin --> breaks down either fibrin or fibrinogen --> fibrin degradation products
53
function of antithrombin III
blocks abnormal clot formation
54
fibrin degradation product that allows differentiation between normal fibrinolysis and abnormal clot formation
D-Dimer
55
normal D-dimer
<0.5 mg/ml
56
elevated D-dimer indicates excessive ____
clot formation
57
classic reason for elevated D-dimer
DIC
58
continual activation of clotting and fibrinolytic cascades
disseminated intravascular coagulation
59
Lab values in DIC
```
Prolonged PT and PTT
Decreased fibrinogen
Increased D-dimer
Increased thrombin time
Low platelet count
```
60
Hemophilia A is deficiency of?
Factor VIII:C
61
Which hemophilia is “classic” hemophilia?
Hemophilia A
62
Inheritance pattern of hemophilia A
Sex-linked recessive (X chromosome)
63
Severe classification of hemophilia A
Less than 1% factor VIII activity
Severe bleeding
Crippling
Needs treatment
64
Moderate classification of hemophilia A
1-5% factor VIII activity
Occasional hemarthrosis
Treatment needed post-trauma
65
Mild classification of hemophilia A
6-40% factor VIII activity
Rare hemarthrosis
Fairly normal life
Severe bleeding after dental extraction or other minor surgery
66
Hemophilia A lab results
```
Prolonged PTT
FVIII decreased
PT normal
Platelet count normal
Ristocetin aggregation normal
```
67
Treatment for hemophilia A
Recombinant FVIII
Human plasma derived FVIII
DDAVP for mild cases
68
Use of Cryo for factor VIII deficiency
No longer used due to excessive donor exposure
69
Deficiency in von Willebrand disease
VIII:vWF
70
Difference in deficiency in hemophilia A and von Willebrand disease
Abnormality of FVIII complex different
71
Most common factor deficiency
Von Willebrand
72
Von Willebrand bleeding risk when factor activity level is < ___
40%
73
Blood type correlation with von Willebrand deficiency
Levels vary with blood type
| AB > B > A > O
74
Von Willebrand factor is carrier molecule for what factor
VIII
75
Symptoms of von Willebrand disease
Mucosal and cutaneous bleeds
Easy bruising
GI bleeding
Menorrhagia
76
Why is von Willebrand factor essential for platelet function?
Interaction with endothelium
77
Lab results in von Willebrand disease
```
PTT prolonged
FVIII decreased
PT normal
Ristocetin aggregation decreased
platelet count normal
```
78
Treatment of von Willebrand disease
DDAVP
Cryo
Human plasma derived VIII (must contain both FVIII and vWF)
79
Why is recombinant/monoclonal FVIII not used for von Willebrand disease
Does not contain vWF
80
Christmas disease is which hemophilia?
B
81
Factor deficiency in hemophilia B
IX
82
Inheritance pattern for hemophilia B
sex-linked recessive
83
Which hemophilia is more common
A
84
Hemophilia B lab results
PTT prolonged
FIX decreased
PT normal
Platelet count normal
85
Treatment for hemophilia B
Plasma derived factor IX
| Recombinant factor IX
86
Factors contained in plasma derived prothrombin complex FIX
II
VII
IX
X
87
Factor I half life
72-120 hours
88
Factor V half life
12-36 hours
89
Factor VII half life
5-8 hours
90
Factor VIII half life
8-12 hours
91
Von Willebrand half life
22-40 hours
92
Factor IX half life
48-72 hours
93
Factor X half life
48-60 hours
94
Factor XIII half life
72-120 hours
95
How is factor dosage calculated?
1 unit of factor per kg body weight should raise plasma factor level by ~2%
96
Half life application if half life is 8-12 hours
~8 hours after infusion the plasma level will drop by 50%
If starting level is 150%, in 8 hours level will be 75%
In 16 hours level will be 37.5%
In 24 hours level will be 18.75%
97
Causes of fibrinogen deficiency
```
Liver disease
Multiple myeloma
Malignancy
Inhibitors
DIC
Surgery
OB cases
Drugs
```
98
Lab results of fibrinogen deficiency
Prolonged PT
Prolonged PTT
Decreased fibrinogen
99
Treatment of fibrinogen deficiency
Treat underlying cause
| Cryo supportive therapy
100
Prothrombin deficiency causes
```
Vitamin K deficiency
Liver disease
DIC
GI disease
Obstructive jaundice
Coumarin drug intoxication
```
101
Prothrombin deficiency lab results
Prolonged PT
Prolonged PTT
Decreased FII assay
102
Treatment for prothrombin deficiency
Vitamin K
Treat underlying cause
FFP supportive therapy
103
Factor V deficiency causes
```
Inherited Owren’s disease
Parahemophilia
Inhibitors
DIC
Autoimmune disease
```
104
Factor V deficiency lab results
Prolonged PT
Prolonged PTT
Decreased FV assay
105
Treatment for factor V deficiency
Treat underlying cause
| FFP supportive therapy
106
Factor VII deficiency causes
Inhibitors
Liver disease
Coumarin drug therapy
Vitamin K deficiency
107
Factor VII deficiency lab results
Prolonged PT
Prolonged PTT
Decreased FVII assay
108
Treatment for factor VII deficiency
Commercial FVII concentrate
FFP supportive therapy
Vitamin K (unless hereditary VII deficiency)
109
Factor X deficiency causes
Stuart or Stuart-Prower disease
110
Factor X deficiency lab results
Prolonged PT
Prolonged PTT
Decreased FX assay
111
Treatment of factor X deficiency
FFP supportive therapy
| Vitamin K unless hereditary deficiency
112
Factor XI deficiency causes
Autosomal recessive disorder, more common in Jewish families
113
Factor XI deficiency lab results
Normal PT
Prolonged PTT
Decreased FXI assay
114
Treatment for factor XI deficiency
Usually not necessary
| May give FFP if bleeding in surgical situations
115
Factor XII deficiency causes
Rare autosomal recessive disorder
| May exhibit thrombotic episodes later in life
116
Factor XII deficiency lab results
Normal PT
Prolonged PTT
FXII activated by glass in vivo
117
Treatment of factor XII deficiency
Not necessary even in surgical bleeding
118
Factor XIII deficiency causes
```
Umbilical cord bleeding
Poor wound healing
Spontaneous abortions
Abnormal scar formation
Intracranial hemorrhage
Oozing from wounds after 36 hours
```
119
Factor XIII deficiency lab results
Normal PT
Normal PTT
Normal platelet count
Soluble in 5M urea
120
Treatment for factor XIII deficiency
Cryo supportive therapy
