Haemostasis

Question 1

Primary hemostasis has 3 main components. What are they?

Answer 1

• Endothelium injury exposing collagen and releasing vWF
• vWF adheres platelets to endothelium
• Platelets - adhere, change shape, secrete, aggregate

Question 2

What are the Vi-K dependent enzymes related to coagulation?

Answer 2

II, VII, IX, X

Question 3

What factors are from the extrinsic pathway that feed into tenase?

Answer 3

VIIa-TF-Ca2+

Question 4

What factors from the intrinsic pathway feed into tenase?

Answer 4

VIIIa-IXa-Ca2+ - PF3

Question 5

What factors go into prothrombinase?

Answer 5

Va-Xa-Ca-PF-3

Question 6

What causes coagulation inhibition?

Answer 6

Antithrombin III inhibits intrinsic & common pathways
TF inhibitor is an extrinsic pathway inhibitor, inhibits LACI, extrinsic tenase

Question 7

What is fibrinolysis?

Answer 7

Blood clot lysis mediated by serine protease plasmin

Question 8

Plasminogen is activated by…

Answer 8

tPA (tissue plasminogen activator)
UPA (urokinase PA)

Question 9

tPA & UPA activators are inhibited by…

Answer 9

PAI-1 (plasminogen activator inhibitor 1) which binds free tPA

Question 10

plasmin is inhibited by:

Answer 10

alpha2-antiplasmin
alpha2-macroglobulin

Question 11

Plasmin formation is inhibited by

Answer 11

TAFI (thrombin-activatable fibrinolysis-inhibitor)

Question 12

What does TAFI do?

Answer 12

Plays important role in stabilizing the fibrin clot, protecting it from lysis

Question 13

TAFI is activated by

Answer 13

thrombin, especially with thrombomodulin as a cofactor

Question 14

TAFI inactivates…

Answer 14

bradykinin which causes vasodilation, non-vascular smooth muscle contraction, increased vascular permeability, pain

Question 15

What causes hemorrhagic diatheses?

Answer 15

• Deficiency/defective coagulation factors
• Quantitative or qualitative defects of platelets
• Diffuse endothelial injury
• Bleeding including hematoma, sites of mechanical stress, hemarthroses, purpura

Question 16

Prothrombin time tests

Answer 16

the extrinsic and common coagulation pathways

Question 17

Activated partial thromboplastin time tests

Answer 17

the intrinsic and common coagulation system

Question 18

What tube is required for coagulation tests?

Answer 18

Na citrate blood

Question 19

Thrombin time measures

Answer 19

the time it takes to convert fibrinogen to fibrin

Question 20

Activated clotting time tests

Answer 20

the intrinsic system

Question 21

FDP’s increase as…

Answer 21

fibrinogen is cleaved by plasmin

Question 22

D-dimer increases as

Answer 22

X-linked fibrin is cleaved by plasmin

Question 23

ATIII decreases as

Answer 23

it is consumed by binding clotting factors

Question 24

PT increases when

Answer 24

APTT increases

Question 25

When would you suspect Bleeding diathesis?

Answer 25

- prolonged bleeding after a minor cut/wound - bleeding defect in newborns - access to poisons - purpura - small bleeding sites in skin & MM's - Petechiation - pinpoint bleeding MM's, platelets decreased - bleeding into body cavity or into muscle/eye - Txt w/ aspirin, estrogen, bute, heparin

Question 26

What are some hereditary bleeding disorders?

Answer 26

Haemophilia A-D

Question 27

What results would you expect if a patient had haemophilia A & B?

Answer 27

prolonged APTT, normal PT

Question 28

Hemophilia A is sex-linked in what species?

Answer 28

dog, cat, horse

Question 29

An increase in APTT may demonstrate...

Answer 29

Classic hemophilia A (VIII)

Question 30

Hemophilia A affects...

Answer 30

VIII (Antihemophilic factor A)

Question 31

Hemophilia B affects...

Answer 31

IX (Christmas factor)

Question 32

Hemophilia C affects...

Answer 32

XI (plasma thromboplastin antecedent - PTA)

Question 33

Hemophilia D affects

Answer 33

XII (Hageman factor)

Question 34

What are some inherited coagulation defects?

Answer 34

I: Congenital afribrinogenemia II VII VWF deficiency

Question 35

What are some acquired disorders?

Answer 35

Vit K Def/antagonism DIC - consumption coagulopathy Angiostrongylus vasorum

Question 36

What are some clinical signs of vit K deficiency/antagonism?

Answer 36

Anemia Weakness Pallor Epistaxis Weakness

Question 37

What abnormalities might be see on coagulation tests when DIC is in progress?

Answer 37

APTT, PT increases FDP/D-Dimer + ATIII decreases

Question 38

Antiaggregant of platelets produces

Answer 38

nitric oxide aka EDRF (endothelium-derived relaxation factor)

Question 39

What are common anticoagulants?

Answer 39

Heparin Thrombomodulin TPA

Question 40

DDAVP is used to treat

Answer 40

vWF deficiency