Lab 3 - HAEMOSTASIS Flashcards
(122 cards)
1
Q
What does haemostasis mean
A
Hemostasis is the name of a group of processes initiated in the body in order to stop bleeding in case of tissue and/or blood vessel injuries.
2
Q
What are the Major groups of hemostasis disorders.
A
- Vasculopathy
- Thrombocytopathy
- Coagulopathy
3
Q
What is Vasculopathy
A
- *The first step** of the hemostasis process
- *Decreased ability** of vasoconstriction in case of blood vessel injury
4
Q
What is Thrombocytopathy
A
- *The second step** of haemostasis
- *Decreased ability** of platelets to aggregate and adhere to the site of injury, and formation of the primary thrombocyte-thrombus,
5
Q
What is Thrombocytopenia
A
Decreased amount of thrombocytes in the blood
6
Q
What is coagulopathy
A
The third and final step of haemostasis
Problems with the extrinsic-, intrinsic-, or common pathway of the coagulation cascade, which
ends with the formation of a polymerized fibrin network, which keeps thrombocyte thrombi at the site of injury,
7
Q
Which test are performed by the side of the animal
A
1 Signs of increased bleeding tendency:
2 Capillary resistance (human medicine)
3 Bleeding time
(buccal mucosal bleeding time test, BMBTT)
4 The appearance of the first fibrin strand (clotting time)
5 The appearance of the clot (clotting time on different surfaces)
6 Clot retraction time
8
Q
Where do we look for signs of increased bleeding tendency
A
Signs of increased bleeding tendency:
- on the skin and mucous membranes:
- *anemia**, petechia, ecchymosis,
suffusion;
in the thoracic cavity: haemothorax;
in the abdominal cavity: hemoperitoneum;
in the gastrointestinal tract: haematemesis, melena
9
Q
What do you know about the Capillary resistance test
A
- The test is usually used in human medicine,
- Also called Rumpel-Leed-test.
- Ligarture on arm
- Check for PETECHIA on palmar side
3- 5 min
Tells us about the capillary function
10
Q
Capillary function due to disease
A
Capillaries are fragile in case of VASCULITIS or other diseases that affect the wall of blood vessels
11
Q
What does bleeding time (BT, BMBTT) depend on?
A
Depends on
Thrombocytic function, the Platelet count, and the Capillary function.
12
Q
What is Bleeding time a test for
A
1. Thrombocytopenia
2. Thrombocytopathy
3. Vasopathy
NOT COAGULOPATHY
13
Q
What is normal BT
A
3-5 min
No danger in clinical bleeding if the platelet count is above 50*10^9/L
14
Q
What is Coagulation time (CT) a test for
A
Test for COAGULOPATHIES
15
Q
In CT test what blood do we use
A
Fresh, native (not anticoag) whole blood sample
Not cause increased tissue factor (Factor III)
= initiates coagulation cascade
16
Q
In CT what methods do you use
A
2 syringe method
17
Q
In CT - where/how can you examin it
A
The appearance of Fibrin strand
CT on watch glass
CT in plastic syringe
CT in glasstube
CT in ACT tube
18
Q
In CT - when does the first fibrin strand appear
A
Within 1-2 min
19
Q
In CT - on watch glass
A
Treated with paraffin or wax
(scratch may initiate coagulation cascade)
Solid like gelatin
7-15min
20
Q
In CT - in plastic syringe - time
A
10-12min
21
Q
In CT - in glasstube - time
A
4-5 min
22
Q
In CT - in ACTtube - time
A
3min
23
Q
CT in ACT (activated clotting time) tube
A
SiO2 in 37 degrees –> Activates Factor XII (Hagemann, contact factor)
Factor XII activates Factor IX –> Kallikreinogen –> Kinigogen
= Fibrolytic Pathway
Move tube every 15-20sec
24
Q
What is platelet (Thrombocytic) Count important for
A
Especially when BT, BMBTT is INCREASED
Petechia are visuable on skin or mucous membranes
25
Platelet (Thrombocytic) count is measured from which blood?
ANTICOAGULATED BLOOD
**Na2+, K2, EDTA**
26
Platelet (Thrombocytic) Count
Methods
3 **Methods**
27
Platelet (Thrombocytic) Count
Method 1
0. 1 ml **EDTA** anticoagulated blood sample
0. 9 ml p**hysiological saline solution,**
sedimented for **2 hours.**
**upper layer**
**Bürker chamber** (hemocytometer).
count the **number of platelets in 10 rectangles.**
the number should be **multiplied by 10^9**
**= number of platelets in 1 liter blood.**
28
How can you make the process quicker in case of platelet count
the process can be made quicker if the sample in **NaCl-solution** is **centrifuged on 1500/min.**
29
Thrombocyte counting in
Bürker chamber is not accurate.
True or False
**True**
30
How to estimatete Platelet count with
Method 2
Platelet count can be estimated by using a **blood smear.**
31
Platelet count method 2
Magnification and count
Magnification: **1000X**
Count: **20\*10^9**
32
Platelet count Method 2
This method is also very uncertain, however checking a blood smear for any purpose can be very important.
TRUE OR FALSE
TRUE
33
Platelet count Method 2
What does big thrombocytes tell you
The propper fuction
34
Platelet count Method 2
How is low thrombocytic count measured?
Automatic cell counter
35
Platelet count method 3
How to measure?
Platelet count can be measured by using **automatic cell counters.**
36
Platelet count Method 3
Which particles are taken as platelets
Particles of the blood between **5-30 fl** volume
are taken as platelets.
37
Platelet count method 3
What can happen due to regenerative processes of the bone marrow
(Big platelets)
Sometimes in regenerative processes of the bone marrow, when there are many young (big) platelets circulating i.e. in case of
chronic blood loss, or physiologically in cats and in King Charles spaniels
= Average thrombocytic volume can be so high, that these **big platelets are taken as red blood cells by the counter.**
38
Platelet count method 3
Why are evaluation of blood smares important
an important step of the **diagnosis of thrombocytic disorders!**
39
Platelet count
What are the General Platelet Count
**200-800 x10^9/l**
40
What are the Major causes of thrombocytopenia:
**1. decreased production** of thrombocytes in the bone marrow
**2. increased utilization** of thrombocytes: **DIC** (disseminated intravascular coagulopathy)
**3. increased destructio**n of thrombocytes : autoimmune thrombocytopenia (AITP)
**4. increased sequestration** of thrombocytes: in case of (chronic) splenomegaly
**5. increased loss** of thrombocytes: subacute/chronic bleeding
41
Clot Retraction Test
If you leave the blood in a ube for some hours, what will happen?
If you leave the blood clot in a tube for some hours, it will become **smaller,** and **serum will appear around the
clot.**
42
Clot retraction test
If you leave the blood clot in a tube for some hours, it will become smaller, and serum will appear around the
clot. But WHY?
The reason for this clot retraction is that platelets contain a **contractile protein** called **thrombostenin**,
43
Clot retraction test
What is Normally the volume of serum released by the clot within one hour
approx. 25% of the whole volume of the
initial clot..
44
How can we measure Thrombocytic function
Estimated by performing Clot Retraction time test
If the clot retraction is **slower** or **does not
happen at all**, we can suspect**thrombocytopathy.**
45
When do we use the Platelet aggregation test
When we suspect thrombocytopathy, i.e. von Willebrand disease.
46
Using the Platelet aggregation test what do we use, and to estimate what?
use a**ggregometer** to estimate the **aggregating ability** of platelets correctly.
47
Platelet aggregation test
What type of blood should you prepare?
Where do you find the platelet rich plasma?
Propperties of the fluid?
We have to prepare a **citrated blood sample** and the
**upper layer** should be used for this analysis.
This is the **platelet rich plasma.**
This fluid is **slightly opaque.**
48
Platelet aggregation test
Which drugs causes exaggerated aggregation of platelets
ADP,
epinephrine etc.
49
Platelet aggregation test
What can be analysed by a spectrophotometer.
The **speed** and the **rate** of the **clearing** can be analysed by a spectrophotometer.
Nummerical value
50
**Thrombocytic morphology**
**Size**
Thrombocytes have **1-2 μm diameter.**
**Horses, sheep, cattles**, have the smallest platelets **(3-5 fl)**,
**Dogs and swine** have bigger **(7-8fl)**,
**Cats** have the biggest **(10-15fl)** thrombocytes.
51
Thrombocytic morphology
Center
Edges
Center= GRANULOMER
Edges= HYALOMER
52
Major causes of thrombocytopathies:
1. improper **development of platelets,**
for example because of hereditary **glycoprotein deficiencies**, etc.
2. **von Willebrand’s disease** (see later)
3. **U****raemia, liver failure**,**myelo**-, and/or**lymphoproliferative diseases**,**NSAID** treatment, etc.
53
In case of **thrombocytopenia**, **thrombocytopathies** and **vasopathies**
- What can we expect?
Besides normal coagulation, we **cannot expect**
**signs of a really severe bleeding disorder**
(suffusion, haematoma, haemothrorax, haemoperitoneum),
Because these are prevented by the formation of **polymerized fibrin strands** (fibrin thrombus) at the end of the coagulation
cascade.
54
In case of **COAGULOPATHY**
## Footnote
**- What can we expect?**
Besides normal thrombocytic and blood vessel function and normal platelet count may lead
to the aforementioned **severe bleedings**, and sometimes **bleeding to death,** because t**hrombocytic thrombi are not
stable without a fibrin network**, and in case of a big blood vessel injury, the**power of blood flow can sweep away
the thrombocyte-thrombus from the wound**!
55
Major alterations of the basic tests in different haemostasis disorders:
COAGULOPATHY
**INCREASED CT**
Normal BT, PC (platelet count) and Platelet morphology
56
Major alterations of the basic tests in different haemostasis disorders:
THROMBOCYOPENIA
**INCREASED** BT, **DECREASED** PC
Normal **CT** and Platelet morphology **altered or not**
57
Major alterations of the basic tests in different haemostasis disorders:
THROMBOCYTOPATHY
INCREASED BT
Normal CT, PC (platelet count), and Platelet morphology **altered**
58
Major alterations of the basic tests in different haemostasis disorders:
**VASCULOOPATHY**
**INCREASED BT**
Normal CT, PC (platelet count), and Platelet morphology
59
How do you examine Coagulopathies
By using more specific **“global “**tests, so that we can evaluate, which group(s) of factors are **not functioning properly.**
**Citrated blood should be used** (citrate prevents coagulation by binding
**calcium ions**), which means, **3,8 % Na-citrate:blood = 1:9.** (Prepared tubes are commercially available, usually
blue cap)
60
What is the ratio of a prepared citrate sample?
3,8 % Na-citrate:blood = **1:9.**
61
```
Prothrombin time (PT):
When do you have to perform it
```
This test must be performed **within 1 hour** after sampling.
62
Prothrombin Time (PT)
Bloodsample mix
Blood samples should be mixed with **3.8% sodium
citrate in 9:1 dilution** (4.5 ml of blood and 0.5 ml of Na-citrate).
Then **centrifuge** the samples in **3000 rpm for 10 min**. and separate the (decalcinated) **plasma** from the **sediment**.
The plasma must be kept on **37 degrees.**
63
Prothrombin Time (PT)
What does the reagent contain
The reagent **(Simplastin)** for PT evaluation contains:
**rat uterus tissue** **homogenate** as tissue thromboplastin (Factor III.), and **CaCl2**. The reagent must be kept at **37 degrees before** use.
64
Evaluation of Prothrombin time (PT)
The evaluation can be performed by using a
**1. coagulometer** (see on the practical!) or in
**2. test-tube.**
**200 μl reagent**
should be mixed with 1**00 μl decalcinated (citrated!) plasma** and the time of coagulation should be noted.
65
Normal Prothrombin time (PT)
Normal PT: **10-15 sec.**
66
What does the Prothrombin time (PT) give information about
The function of the **extrinsic pathway**,
- because the **coagulation cascade is triggered** by **adding tissue factor (and calcium ion)** to the dacalcinated plasma sample.
67
**Factors** involved in Prothrombin time (PT) are:
**VII., X., V., II., I., XIII.**
68
Activated partial thromboplastin time **(APTT):**
For this test **decalcinated plasma** should be used similarly to PT.
True or false
True
69
The **reagent** of Activated partial thromboplastin time test (APTT) contain
The **reagent (Silimat)** contains **rabbit brain homogenate** as **PF3 (platelet factor 3)** and
**Micronised silica** as c**ontact activator.**
70
Activated partial thromboplastin time (APTT): The MIX
**100 μl decalcinated plasma** should be mixed with
**100 μl reagent** and
the mixture kept on **37 degrees**
then **100 μl of 0.025 mmol/l CaCl2 solution** should be added and from this moment the **time of coagulation should be noted**.
71
Normal Activated partial thromboplastin time (APTT):
Normal APTT: **20-30 sec..**
72
What does the Activated partial thromboplastin time (APTT) give us information about?
The function of the **intrinsic pathway**
because the cascade is triggered by providing **surface activation** (imitating the effect of free **collagen**, which appears on the **inner surface** of the vessels in case of blood vessel injury), and **adding platelet factor 3 (PF3)** and **Ca 2+** for the **activation of factor X**. (remember the
coagulation cascade!!)..
73
Factors involved in **Activated partial thromboplastin time (APTT)** are?
**XI., IX., VIII., X., V., II., I., XIII.**
74
Thrombin time (TT) depends on
```
Thrombin time (TT)
By performing this test, **decalcinated plasma should be simply mixed** with a reagent **containing thrombin only**.
```
In this case coagulation time depends on the **concentration of fibrinogen** and **Factor XIII.in the plasma.**
Obviously, this test can also be used for the **estimation of fibrinogen concentration** (suspecting a normal factor XIII. level in
the blood).
75
Intrinsic pathway problem
1. hemophilia A-factor VIII. deficiency;
2. hemophilia B-factor IX. deficiency;
3. von Willebrand's disease)
76
Intrinsic pathway problem
APTT
PT
**APTT increased**
77
Extrinsic pathway problem
1. Factor **VII** deficiency, **dicumarol toxicosis - first stage)**
78
Extrinsic pathway problem
APTT
PT
**PT INCREASED**
79
Common pathway problem
## Footnote
1. Liver disease
2. decreased. prod. of coag. factors,
3. DIC, dicumarol toxicosis - second stage,
4. Factor **X**. and/or **V.** and/or **II.** and/or **I.** and/or
* *XIII**. deficiency)
80
Common pathway problem
APTT
PT
APTT and PT **INCREASED**
81
In the **early stage of dicumarol** (or warfarin) toxicosis both **APTT and PT** is i**ncreased,**
True or false
**False**
In the **early stage of dicumarol** (or warfarin) toxicosis only **PT is increased,**
82
In the early stage of dicumarol (or warfarin) toxicosis **only** **PT** is **increased**, and **later APTT is increased, too.**
**True or false**
**True**
83
What is the competitive antagonist of vitamin K.
Dicumarol
84
What is VIT D responsible for
* *Gamma-carboxylation** of:
* *1. Proconvertin** (Factor VII),
**2. Christmas** (Factor IX),
**3. Stuart-Prower** (Factor X) and the
**4. Prothrombin** (Factor II), as
they are **Ca2+ dependent factors,**
85
**Vitamin K deficiency** causes ?
The inability of these factors to **bind calcium.**
86
Which factor will be deficient first.
**Factor VII**. has the shortest half life, so this factor will be deficient first.
87
Which test will show the deficiency problem first.
When the P**rothrombin Time is increased** when
there is **factor VII deficicenc**y, so this test will show the problem first.
88
What is the Function of **Vitamin K**
To **exaggerate** the **post-synthetic gamma-carboxylation** of those factors in the **liver**.
This makes these factors to be able to **bind Ca2+,** and thus become
**functionally active.**
89
In case of **vitamin K deficiency** of any origin, **improperly carboxylised prothrombin** can be detected by using ?
**ELISA** (Enzyme Linked Immunosorbent Assay) test, called **PIVKA II.** (Proteins Induced by Vitamin K Absence)
90
Fibrin degradation products (FDP)
What is Fibrinolytic pathway is responsible for
The Fibrinolytic pathway is responsible for keeping the **clot formation** within **normal limits.**
91
What are the Clot inhibitors
**(antithrombin III.**, **alpha2-macroglobulin,** **alpha1-antitripsin,** **heparin** – the latter increases the **binding of antithrombin III to thrombin)**
are able to **bind to thrombin and neutralize it.**
92
After complete coagulation, the clot is usually not needed anymore, so it should be broken down by .......
**fibrinolytic enzymes.**
93
What are the activators of factor XII. (Hageman).
**1. Free collagen fibres,** (exposed at the site of blood vessel injury),
**2. kininogen** and
**3. kallikrein** are the activators of factor XII. (Hageman).
94
XII.a (activated form of factor XII. ) further activate
the **extrinsic pathway,**
95
**XII.a** (activated form of factor XII. ) further activates the **extrinsic pathway** and is able to form.......
**kallikrein** from **prekallikrein.**
* *Kallikrein** activates the **kininogen system**, also, forming
* *Bradykinin** (an activated form of kininogen), which is a **very potent mediator of pain.**
96
What is an activated form of kininogen, and what is it a strong mediator for?
**Bradykinin** (an activated form of kininogen), which is a very potent **mediator of pain.**
97
What is the most
important activator of plasminogen.
**Kallikrein**
98
What is the activated form of plasminogen?
* *Plasmin** (activated form of plasminogen) is an **endopeptidase**, which can
* *cleave fibrin strands into small pieces.**
99
\
Before the total degradation of polymerized fibrin strands, increased
level of
**fibrinolysis-products**, f**ibrin dimers** and monomers (so called: “fibrin degradation products or proteins,
FDP”) can be measured in the blood.
100
What is the fuction of FDP
Fibrinolyticenzyme removes clot - elevates level of FDP
but its **not accurate** because the degradation product could come from both - **fibrinogen/fibrin**
101
What to use instead of FDP ?
**D-Dimer level**
To distinguish btw fibrin and not fibrinogen
102
What is helpfull with D-Dimer
Helpful in **early** diagnosis of **disseminated Intravascular coagulopathy (DIC)**
103
What is DIC
**DIC is a common acute disorder**
(that requires accurate and quick laboratory diagnosis)
Usually a **secondary disease,** caused by **primary diseases**
**LIFETHREATHENING**
104
Name some primary causes that could have caused DIC
**Septicemia**
**Pancreatitis**
**Burn injuries**
**Necrosis of big tumors**
**Shock**
**Polytraumatisation**
105
What could be the first sign of DIC
Positive FDP or D-dimer test
106
What is present simultaneously many places in the body during DIC
Formation of Microthrombus + Fibrinolysis
Because of severe damage(necrosis) or Blood vessel injuries
107
What is **“consumptional coagulopathy”.**
In case of DIC, **microthrombus formation** and **fibrinolysis** are
present at many different places in the body s**imultaneously**, so **coagulation factors** and **platelets** are consumed very quickly during this process.
108
What happens during **Consumptional Coagulopathy**
**Coagulating factors** and **platelets** are consumed
109
Lab DIAGNOSIS of DIC
## Footnote
CT, BT, Platelet count, PT, APTT and TT?
FDP and D-Dimer?
SCHYSOCYTES and/Or BURR CELLS
INCREASED
**CT, BT, PT, APTT** and **TT**
**FDP** and **D-Dimer**
DECREASED
**Platelet count**
SCHYSOCYTES and/Or BURR CELLS
in blood smare = **damaged red blood cells**
110
Diagnosis of Von WILLEBRAND Disease
Which species
**Human** and **dog** (Dobberman Pincher)
111
Diagnosis of Von WILLEBRAND Disease
Which factor is deficient
Von Willebrand factor
**FACTOR VIII is deficient**
112
Diagnosis of Von WILLEBRAND Disease
What are the 3 main parts of complete factor VIII
1. Von Willebrand factor – **platelet adhesion** and **aggregation**,
2. **VIIIc** – is the antihemophilic factor, and the
3. **Factor VIII related antigen** – is the **hapten** that is the determinable
part, and is **bound strongly to von Willebrand factor.**
113
How does BT(BMBT), Clot reaction ability look like in the case of a dog with VON WILLEBRAND DISEASE
INCREASED
**BT, BMBT**
DECREASED
**Clot reaction ability**
Coagulation disorder sometimes
114
The specific diagnosis of VON WILLEBRAND DISEASE is based upon
The detection of the **lack** of von **Willebrand-related antigen.**
115
What happens to BT, Platelet count, APTT and PT due to
**THROMBOCYTOPENIA**
**BT** is **INCREASED**,
**Platelet count** is **DECREASED**
APTT and PT = Unchanged
116
What happens to BT, Platelet count, APTT and PT due to
**THROMBOCYTOPATHY**
**BT is INCREASED,**
Platelet count, APTT and PT is UNCHANGED
117
What happens to BT, Platelet count, APTT and PT due to
* *Intrinsic pathway disorder**
(pl. haemophilia A, B)
**INCREASED APTT**
BT, Platelet count and PT is unchanged
118
What happens to BT, Platelet count, APTT and PT due to
**Factor VII Deficiency**
**Factor VII Deficiency (**in early phase of DICUMAROL toxicosis)
**PT** is **INCREASED**
BT, Platelet count and APTT is unchanged
119
What happens to BT, Platelet count, APTT and PT due to
**Disorders of the common pathway**
**Disorders of the common pathway**
(Liver faiure, Factor X deficiency, **late** stage of **DICUMAROL** toxicosis)
**BT** is **unchanged** or **INCREASED**,
**APTT** and **PT** is **INCREASED**
**The platelet count** is unchanged
120
What happens to BT, Platelet count, APTT and PT due to
**DIC**
**BT, APTT** and **PT** is **INCREASED**
**Platelet coun**t is **DECREASED**
121
What happens to BT, Platelet count, APTT and PT due to
**VON WILLEBRAND-DISEASE**
**BT** is **INCREASED**
**APTT is unchanged or INCREASED**
Platelet count and PT is unchanged
122
