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Lab diagnostics > 3. Changes of haemostasis > Flashcards

3. Changes of haemostasis Flashcards

1
Q

What are the major groups of hemostasis disorders?

A
  1. Vasculopathy
  2. Thromobocytopathy/penia
  3. Coagulopathy
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2
Q

What is meant by vasculopathy?

A

The decreased ability of vasoconstriction in case of blood vessel injury, it is the first step of the haemostasis process

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3
Q

What is meant by thrombocytopathy?

A

The decreased ability of platelets to aggregate and adhere to the site of injury, and the formation of the primary thrombocyte-thrombus - the second step of hemostasis process

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4
Q

What is meant by thrombocytopenia?

A

Decreased amount of thrombocytes in the blood

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5
Q

What is meant by coagulopathy?

A

When there is an problem with the extrinsic or intrinsic, common pathway of the coagulation cascade, it ends with the formation of a polymerized fibrin network, which keeps thrombocyte thrombi at the site of injury - this is the third and the final step of hemostasis

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6
Q

What are the tests that we can perform by the side of the animal

A
  • sign of increased bleeding tendencies
  • capillary resistance
  • bleeding time - BMBTT
  • appearnace of the first fibrin strand
  • appearance of the clot
  • clot reaction time
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7
Q

what is another name for the capillary resistance test?

A

Rumpel-Leed-test

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8
Q

How is the capillary resistance test performed

A

put a ligature above the elbow (tornique) and check the palmar side of the lower arm for petechie. they should normally appear after 3-5 min

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9
Q

In what cases will more petechia appear during the capillary resistance test?

A

if the capillaries are not functioning properly, more fragile - vasculitis or other diseases affecting the wall of the blood vessels

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10
Q

What are we testing for with the blleding time test?

A

thromobcytopenias

thrombocytopathies

vasopathies

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11
Q

how do you perform bleeding time test?

A

make a 0,1-0,2mm deep cut, 0,5cm long incision on the skin of the inner part of the external ear or on the buccal muscosal surface. wipe away the blood under the cut, check for the tming when it stops bleeding
normal BMBT is 3-5min

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12
Q

What do you test with coagulation time test?

A

coagulopathies

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13
Q

In what state should the blood be in case of testing the coagualtion time?

A

fresh, native whole blood sample

  • no antigoaculants

the test should be performed immediately after taking the blood sample

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14
Q

How should the blood be drawn in case of taking blood sample for a coagulation test?

A

one precise venipuncture, two syringe method

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15
Q

What are the different methods that coagulation time can be tested?

A
  • appearnce of the first fibrin strand
  • clotting time on watch glass
  • CT in plastic syringe
  • CT in glass tube
  • CT in activated clotting time tube
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16
Q

How is the “appearance of the first fibrin strand” performed?

A

some drops of blood are put onto a glas slide, move the tip of the needle back and forth until the first fibrin strand apperas

1-2min

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17
Q

How is “clotting time on watch glass” performed?

A

put parrafin/wax treated blood onto a watch glass, check the complete ciagulation time

7-15min

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18
Q

How is “CTin plastic syringe” performed?

A

put the fresh blood into a plastic syringe and check the time of the complete coagulation

10-12 min

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19
Q

How is the “CT in glass tube” test performed?

A

put fresh blood into a glass test tube and check the time of the complete coagulation

4-5 min

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20
Q

How is the “CT in ACT” test performed?

A

put the frsh blood into a glass test tube that contains SiO2, put in a thermosate, and check the time for teh complete coagulation- slowly move the tube ever 15-20sec

normal: 3min

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21
Q

Why would you use SiO2 in a cioagulation test?

A

SiO2 will activate facto XII

which activates IX and kallikerinogen, kiniogen

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22
Q

When is it important to do a platelet count?

A

when the BT, BMBT is increased

visible petechie on skin and mucous membrane

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23
Q

What blood should be used to count platelets?

A

anticoagulated blood - Na1 or K2EDTA

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24
Q

How is the first method for counting platelets performed?

A

mix 0,1ml blood with 0.9ml physiological saline

let it sediment for two hours

drip a drop from the upper layer into burker chamber

count in 10 rectangles

multiply the number by 10^9 - this will be the number of platelets in one litre of blood

the process can happen quicker if we sentrifuge it

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25
Q

How is the second method of counting platelets?

A

by using a blood smear

if you find one platelet in one view by 1000x magnification it means you have 20x10^9/l platelet count

more important is to check the arrangement - aggregates

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26
Q

How is the thrid method of coutning platelet and also the best one?

A

The automatic cell counter

  • particles between 5-30 fl are tkaen as platelets
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27
Q

In what cases might the automatic cell counter become confused about what is what?

A

Large platelets: regenerative processes, chronic blood loss, cats, king charles spaniel
Taken as RBC instead

Small RBC: taken as platelets

Thrombocyte aggregates: WBC - platelet count is measured to be normal or low, WBC i increased

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28
Q

What is the general platelet count?

A

200-800x10^9/l

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29
Q

What are the major causes of thrombocytopenia?

A
  1. Decreased production of thrombocytes in the bone marrow
  2. increased utilisation of thrombocyte: DIC
  3. increased destruction of thromobcytes: autoimmune thromobcytopenia
  4. increased sequestration of thrombocytes: splenomagaly
  5. increased loss of thrombocytes: subacute/chronic bleeding
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30
Q

What is the clot retraction test?

A

its when you leave a blood clot in a tube for some hours, you will see that it becomes smaller and the serum will appear around theh clot. the contractile protein thrombostenin will be the cause of this retraction - and we can test the thrombocytic function in this way

within one hour 25% of the whole volume of the initial clot should be waht is left

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31
Q

How do you perform a platelet aggregation test?

A

aggregometer is used to estiamte the aggregating ability of platelets, we need citrated blood sample and the upper layer is used

the sample is pput into a cuvette and some drugs are added to help cause aggregation - ADP, epinephrine

the speed of the aggregation can be measured by a spectrophotometer

32
Q

Diamter of thrombocytes?

A

1-2 micrometer

33
Q

Different thrombozyte sizes for different species

A

Horse, sheep, cattles: smallest - 3-5fl

Dogs, swine: 7-8fl

cats: biggest - 10-15fl

34
Q

What are the major causes of thrombocytopathies?

A
  1. improper development of platelets, hereditary glucoprotein deficiencies
  2. Von willebrand’s disease
  3. Uremia, liver failure, myelo-, and/or lymphoproliferative disease, NSAID treatmetn
35
Q

can we expect signs of a really severe bleeding disorders in case of thrombocytopenia, thrombocytopathies and vasopathies?

A

no, beacuse they are prevented by the formation of polymerised fibrin strands at the end of coagulation cascade

36
Q

Which conditions may cause really severe bleeding, bleeding to death?

A

coagulaopathies, becuase thrombocytic thrombi are not stable without a fibrin network

37
Q

What alterations of the basic tests can be seen in coagulopathy?

A
  • BT: no change
  • CT: increased
  • PC: no change
  • platelet morphology: no change
38
Q

What alterations of the basic tests can be seen in thrombocytopenia?

A

BT: increased

CT: no change

PC: decreased

platelet morphology: altered or not

39
Q

What alterations can be seen of the basic tests in case of thrombocytopathy

A

BT: increased

CT: no change

PC: decreased

platelet morphology: altered

40
Q

what alterations can be seen on the basic tests in case of vasculopathy?

A

BT: increase

CT: no change

PC: no change

platelet morphology: no cange

41
Q

what is the function of citrated blood?

A

binds Ca ions

42
Q

What is the prothrombin time test giving us information about?

A

the function of the extrinsic pathway

43
Q

How do you measure the prothrombin time?

A

The blood sample is mixed with sodium citrate (9:1) and then it is centrifuged for 10 min (3000rpm) the reagent used is containing rat uterus tissue as tissue thromboplastin and CaCl2

the testing is performed by using coagulometer or in test-tube

44
Q

What is normal prothrombin time?

A

10-15sec

45
Q

What factors are involved in Prothrombin test?

A

VII
X
V
II
I
XIII

46
Q

What are we testing with activated partial thromboplastin time?

A

the instrinsic pathway

47
Q

How is APTT performed

A

activated partial thromboplastin time

decalcinated plasma (sodium citrate) plasma mixed (1:1) with a reagent made of rabbit brain (PF3) and micronised silica as contact activator. CaCl2 solution should be added and then the coagulation sould be noted

48
Q

What is the normal APTT

A

20-30sec

49
Q

What factors are involved in APTT

A

XI
IX
VIII
X
V
II
I
XIII

50
Q

What is tested with thrombin time?

A

the concentration of fibrinogen and factor XIII in the plasma

51
Q

What can cause problems with the intrinsic pathway?

A
  • hemophilia A - factor VIII deficiency
  • hemophila B - factor IX deficiency - von willebrand’s disease
52
Q

What can cause problems with the extrinsic pathway?

A

Factor VII deficiency

dicumarol toxicosis

53
Q

qhat can be causes of common pathway problem?

A
  • liver disease
    • decreased production of coagulation factors
  • DIC
  • dicumarol toxicosis
  • Factor X and/or V. and/or II and/or I and /or XIII deficiency
54
Q

What is dicumarol an antagonist of?

A

vitamin K

55
Q

What is the role of vitamin K in coagulation?

A

Gamma carboxylation of

  • proconvertin - VII
  • Christmas - IX
  • Stuart-prower - X
  • prthrombin - II

these are Ca dependent factors, vitamin K deficiency causes inability of these factors to bind to Ca

56
Q

List the order of the intrinsic pathway

A
  1. XII
  2. XI
  3. IX
  4. VIII
  5. PF3
  6. V
  7. X
57
Q

List the order of the extrinsic pathway

A
  1. III
  2. VII
  3. X
58
Q

Lis the order of common pathway

A
  1. X
  2. II
  3. I
  4. XIII
59
Q

What is PIVKA II?

A

ELISA test used to detect improperly carboxylised prothrombin (Vitamin K deficiency)

60
Q

What is the fibrinolytic pathway responsible for?

A

keeping the clot formation within normal limits

clot inhibitors are able to bind to thrombin and neutralise it

61
Q

Name some clot inhibitors

A

antithrombin II

alpha2-macroglobulin

alpha-1-antitripsin

heparin (increases the binding of antirheombin III to thrombin)

62
Q

What does kallikrein activate?

A

factor XII

and

kininogen system - bradikinin (pain moderator)

63
Q

Whhich is the most important plasminogen?

A

kallikrein

64
Q

What is plasmin?

A

is an endopeptidase which is the activated form of plasminogen. it can cleavefibrin strands into small pieces

65
Q

What can be measured in the blood before the toatal degradation of polymerised fibrin strands?

A

increased level of fibrinolysis-products

fibrin dimers and monomers

66
Q

what is the most accurate way to detect firbrinolysis?

A

examination of D-dimer level in the blood, only derivated from fibrin

67
Q

What is FDP and D-dimer tests based on?

A

latex agglutination method and fresh citrated plasma should be used

68
Q

Which disease is detected using FDP and D-dimer?

A

early diagnosis of DIC

(disseminated intravascular coagulopathy)

69
Q

What is DIC?

A

disseminated intravascular coagulopathy

microthrombus formation and fibrinolysis are present at many different places of the body, because of severe tissue damage or necrosis, blood vessel injury.

70
Q

What would the laboratory diagnosis of DIC look like

A

CT: increased

BT: increased

PC: decreased

PT: increased

APTT: increased

TT: increased

Fibrin degradation products and D-dimer: increased

apperance of schysocytes and/or burr-cells in blood smears

71
Q

What is wrong when you have Von Willerbrand’s disease?

A

the von willebrand factor, factor VIII is deficient

72
Q

What are the three main factors of factor VIII?

A

von willebrand factor: platelet adhesion and aggregation

VIIIc: antihaemolytic factor

VIII: related antigen

73
Q

What are the alterations of the basic test in case of DIC?

A

BT,BMBT: increase

platelet count: decrease

APTT: increase

PT: increase

74
Q

What are the alterations of the basic test in case of von Willebrand disease?

A

BT,BMBT: increased

platelet count: no change

APTT: same or increase

PT: no change

75
Q

What can we check, when we suspect bleeding tendencies?

A

skin + mucous membrane: anemi, petechia, ecchymoss, suffusion

thoracic cavity: hemothroax

abdomnial cavity: haemoperotoneum

GI tract: hemostasis, melena

Lab diagnostics (6 decks)

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