Hemostasis Flashcards

(97 cards)

1
Q

What is hemostasis?

A

bodys ability to maintain the integrity of the blood and blood vessels

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

Any deviation from normal hemostasis is=

A

disease

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

What responses are in primary hemostasis

A
  1. Vascular response
    2.Platelet response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the vascular response in hemostasis

A

vessel contract and almost immediately when injured, this narrows the lumen of the vessel, which decreases rate of blood loss and creates an area for platelets to adhere

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

What is the platelet response in hemostasis?

A

-become “sticky” (adhere to vessel wall and each other)
-this requires von Willebrand factor, which serves to stabilize the platelet plug
-granules become activated and release, which send a message to begin the Coagulation Cascade

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

What component is in secondary hemostasis?

A

Coagulation cascade

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

What happens in the coagulation cascade?

A

-these factors are made in the liver
-domino effect that eventually forms a stable fibrin clot

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

What is the ultimate purpose of primary and secondary hemostasis?

A

to form a clot and then dissolve that clot

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

Primary hemostasis is the formation of the _ _

A

platelet plug

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

Secondary hemostasis is formation of a stable _ _

A

fibrin clot

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

What is fibrinolysis

A

lysis of clot or thrombus through the activation of plasminogen into plasmin

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

What two components must be present for hemostasis?

A
  1. Vascular component
    2.Platelets, number and function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What 2 parts are in the vascular component of hemostasis?

A
  1. Vascular spasm
    2.Production of factor VIII and vonWillebrand’s factor by endothelial cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Vascular spasm is _ but _ closure of blood vessel by contraction of smooth muscle

A

Immediate but temporary

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

Vascular spasm is stimulated by

A

nervous system response, platelets release thromboxane and serotonin

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

Platelet plug formation is stimulated by

A

vWF

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

vWF resides in the _, subendothelial metrix, and storage granules within endothelial cells and platelets

A

plasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Platelets plug formation consists of

A
  1. adhesion of platelets
  2. aggregation of platelets
    3.secretion of platelets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The following is _ of platelets:
-Platelets stick to subendoethelial surface
-Sticking activates platelets

A

adhesion

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

The following describes _ of platelets:
-Forms platelet plug
-Thromboxane stimulates other platelets to join
-Platelet plug is very short-lived (secs-min)
-Only works on SMALL vessels

A

aggregation

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

The following describes _ of platelets:
-Platelets have lots of substances in them
-Caused by vasoconstriction and further platelet aggregation
-Some substances activate 2 hemostasis

A

Secretion

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

Defects in primary hemostasis may be _ or _ and may be defects in _ or _

A

hereditary or acquired; vascular component or platelet component

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

Acquired vascular component defects

A

vasculitis, collagen deficiency, extensive vascular injury

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

Inherited vascular component defects of primary hemostasis

A

vonWillebrand’s disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the number one acquired defect of primary hemostasis?
thrombocytopenia
26
What is a defect in function of platelets called?
thrombopathia or thrombocytopathy
27
Acquired platelet component defects
drugs, DIC, uremia
28
Hereditary platelet component defect
vWB disease (most common inherited bleeding disorder). platelet fail to adhere to subendothelial collagen
29
What is vonWillebrand's disease?
an inherited bleeding disorder caused by lack of vWF protein
30
What protein circulates in the blood stream and must be present at the site of blood vessel injury in order to control bleeding from that vessel?
vWF
31
vWD is a distinct disorder, it is not _
hemophilia
32
What breed is most commonly affected with the mildest form of vWD?
doberman
33
What breeds are affected with the most severe form of vWD?
Chesapeake Bay Retrievers and Scottish Terriers
34
What breeds have abnormally low concentrations of vonWillebrand factor?
Scottish Terriers and Shetland Sheepdogs
35
Many dogs w/ vWD never show outward evidence of having the disease, but when they do, what do those signs look like?
-Spontaneously hemorrhage from the nose, vagina, urinary bladder, or oral MM -Prolonged bleeding after trauma or sx and bruising or bleeding after a spay/neuter may be first time noticed -in affected dogs w/ uncontrollable bleeding, death may occur
36
Tx of a severe bleeding episode requires
transfusion of canine blood products
37
_ products can be transfused pre-operatively to prevent surgical hemorrhage
plasma
38
_ _ can also be used to improve hemostasis in dogs with mild subtype (Type 1) vWD
Desmopressin acetate (DDAVP)
39
Bleeding from minor injuries may be controlled using
sutures, bandages, or wound glue
40
Dogs affected with vWD should not be given drugs that interfere with normal blood clotting mechanisms, These drugs include:
aspirin, sulfa-type antibiotics, and heparin
41
Dogs having low plasma VWF-ag (below _) are predicted at risk of transmitting or expressing the vWD trait.
50%
42
2 Hemostasis- Synopsis requires
coagulation factors and cofactors (calcium, tissue factors, vitamins)
43
Coagulation factors all made in the _
liver
44
Cascade=
conversion of inactive factors to active factors (like domino effect)
45
Synopsis is _ lasting (minutes to hours)
long
46
When do coagulation factors become activated?
when blood vessel or tissue injury occurs, or in co-operation with platelets, produce a clot at the site of injury
47
There are _ different clotting factors. These factors are activated in a specific sequence following two different pathways or sequences
13
48
What are the pathways of coagulation
intrinsic, extrinsic, and a final common pathway
49
What pathway is described? -ALL component needed for this pathway are present in the blood -Outside tissue damage is NOT needed to stimulate this pathway -Contact activation= activated by contact with collagen and some platelet products -Has factors XII, XI, IX, VIII (cost $12 not $11.98)
Intrinsic
50
What pathway is described? -Requires a tissue factor for activation (tissue factor= thromboplastin) -Thromboplastin is released from injured cells of any kind -Reacts with factor VII
Extrinsic
51
What pathway is described? -Where intrinsic and extrinsic pathways converge -Has 2 stages (prothrombin to thrombin and fibrinogen to fibrin)
Common
52
What are the Vitamin K dependent factors?
II, VII, IX, X
53
In 2 Hemostasis- production of coag factors, the liver synthesizes all factors except part of factor _
VIII (the endothelium produces part of VIII)
54
2 Hemostasis defects may be _ or _
hereditary or acquired
55
2 hemostasis hereditary defects
Hemophilias A (-VIII) B (-IX)
56
What is the most common inherited blood clotting disorder in dogs
Hemophilia A
57
What is the Hemophilia A
the result of a mutation of a specific gene, causing a deficiency of blood clotting Factor VIII, which interferes with the blood clotting cascade
58
Clinical sign of hemophilia A
spontaneous bleeding
59
Dx of hemophilia A
Lab test called APTT (activated partial thromboplastin time) can test for clotting disorders but cannot distinguish among the various types of hemophilia
60
How to get a specific diagnosis of Hemophilia A
by measuring the activity of Factor VIII
61
2 Hemostasis acquired defects
-Deficiency of Vitamin K-dependent factors -Liver disease/failure -DIC
62
What is DIC
Disseminated intravascular coagulopathy -small clots for throughout the body which results in consumption of coagulation factors and then hemorrhage occurs
63
DIC is secondary to conditions like
heat stroke, viremia, endotoxemia, massive necrosis, trauma, septicemia, IV hemolysis
64
Clinical signs of 2 hemostasis defects
-hematomas -bleeding into muscles, joints, and body cavities -delayed bleeding after venipuncture -rarely see petechia or ecchymoses
65
What is fibrinolysis
breakdown of the fibrin clot
66
what is fibrinolysis-synopsis
lysis of a clot or thrombus through activation of plasminogen into plasmin
67
What is plasminogen called when it binds with fibrin (clot) and becomes activated
plasmin
68
Bound plasmin hydrolyses fibrin which produces
FDPs (fibrinogen degradation products)
69
FDPs have _ activity; block thrombin and inhibit platelets
anticoagulant
70
Fibrinolysis defects
Excessive FDP/FSP production (DIC and liver failure)
71
DIC leads to increased levels of
FDP/FSP
72
DIC leads to what due to obstruction of microcirculation
multiple organ dysfunction
73
Clinical signs of DIC
signs of BOTH 1 and 2 hemostasis disorders
74
_ hemostatic disorders are caused by failure of platelet plug formation due to quantitive or qualitative platelet disorders or due to von Willebrand factor deficiency
Primary
75
Clinical signs of primary hemostatic disorders
petechia, mucosal hemorrhage, prolonged bleeding at site of injury
76
Specific primary hemostatic disorders and diagnostic tests
-Thrombocytopenia: platelet count, platelet estimate from blood smear -Platelet dysfunction: in vivo bleeding time, platelet aggregation, drug history and metabolic profile
77
Secondary hemostatic disorders are caused by
failure of fibrin clot formation due to deficiency of one or more coagulation factors
78
Tests to evaluate secondary hemostatic disorders
Rodenticide toxicity: aPTT, pT, vitamin K-dependent factors (II, VII, IX, X) Liver failure: aPTT, PT, fibrinogen Hemophilia: aPTT, factors VIII, IX
79
What does buccal mucosal bleeding time (BMBT) evaluate
both aspects of primary hemostasis, evaluates interaction b/w platelets and endothelium that causes primary platelet plug to form
80
What is normal BMBT for dogs and cats
1-5 mins
81
>5 min BMBT =
thrombocytopenia or platelet dysfunction
82
What tube should be used for activated clotting time (ACT) method
DET tube which activates the intrinsic and common pathways
83
Vitamin K should be given with
food
84
What are the fat soluble vitamins
A, D, E, K
85
Normal ACT in dogs
60-90 sec
86
Normal ACT in cats
<65 sec
87
PTT (partial thromboplastin time) tests _ and _ pathways
intrinsic and common
88
OSPT, PT (prothrombin time) tests _ and _ pathways
extrinsic and common
89
TT (thromboplastin time) detects
decreased fibrinogen
90
FDP evaluates
fibrinolysis
91
Tube used for platelet estimate and count
LTT
92
Tube needed to measure von Willebrand's factor
BTT- MUST BE FULL
93
Mixing ratio for blue top tube
1 part citrate : 9 parts blood
94
BTT is used for tests for coagulation factors of what pathways
intrinsic, extrinsic, and common pathways
95
Extrinsic clotting factor
VII
96
gray TT must be full and can be used for tests for what pathways
intrinsic and common
97
RTT is used for what testing
chemistry profile of liver function