Exam 3: Disorders of Hemostasis

Question 1

How is plasmin formed from plasminogen?

Answer 1

plasminogen along with factor XII and tPA (tissue plasminogen activator - also uses epithelial plasminogen activator)

Question 2

What is one way to determine if clotting has happened?

Answer 2

measuring dimers

Question 3

Which factors are dependent upon Vitamin K?

Answer 3

II, VII, IX, and X

Question 4

A dog has low platelets, what is this called?

Answer 4

thrombocytopenia

Question 5

Which pathway does APTT test?

Answer 5

The intrinsic coagulation pathway

Question 6

Whyaren’t you worried about testing for factor III in the extrinsic coagulation cascade?

Answer 6

without FIII, you’re dead. only need to test for VII.

Question 7

Bleeding disorders 1

What are three factors that deter coagulation?

think simply

Answer 7

a physical barrier
a non wettable surface (is thromboresistant)
and anticoagulant proteins

Question 8

Bleeding disorder 1

What are three factors that encourage coagulation?

Answer 8

contraction of damaged vessel
exposure of collagen factors (reduced blood flow and reducsed shear stresss…clot stability)
production of von willebrand factor

Question 9

bleding disorder 1

Which is more effective, primary or secondary hemostasis? why?

Answer 9

secondary is stronger. primary hemostasis only results in a platelet plug

Question 10

Bleeding disorder 1

What steps are the involved in primary hemostasis - and what proteins and what is their role?

Answer 10

Adhesion: GP1b and vWF allow platelets to adhere
Release reaction: platelets release their granules (proteins talke about below)
Aggregation: aggregation of platelets and platelet plug (upregulation of ADP and vWF bridges)
Platelets faciliatate the coagulation reaction via scramblase

fibrinogen binds platelets to platelets
vWF binds platelets to collagen
Ca2+ is a cofactor in coagulation
ADP+++ helps platelets express a receptor to bind to other platelets

Question 11

Bleeding disorder 1

What are the vitamin K dependent factors? What commonly used household item could interfere with this?

Answer 11

2,7,9,10
rodenticide

Question 12

bleeding disorder 1

What one main enzyme is needed for the coagulation cascade?

Answer 12

thrombin

Question 13

bleeding disorder 1

What are coagulation factors activated by?

Answer 13

exposed TF on endothelial cells, microparticles or extravascular fibroblasts.

also negatively charges surfaces like collagen

Question 14

bleeding disorder 1

what factors are involved in the intrinsic, extrinsic, and common pathways?

Answer 14

intrinsic (inside walmart): 12,11,9,8
extrinsic: (3) and 7
common: 10,5,2,1

Question 15

bleeding disorder 1

How does the common pathway go from factor 10 to a stable clot?

Answer 15

10 to 10a
(Ca, PF3, Va) - prothrombinase
2 to 2a
Fibrinogen to fibrin
(13a)
stable fibrin clot

Question 16

bleeding disorder 1

What clotting factors does the liver make and which ones do macrophages also make?

Answer 16

1,8,9,11,12,13
2,5,7,10

Question 17

bleeding disorder 1

can you run our of TFIII?

Answer 17

Not unless you’re dead

Question 18

bleeding disorder 1

what is involved in the break down of clots?

Answer 18

antithrombin makes up 70% of the anticoagulant proteins, it inactivates thrombin and active factors 12,11,10,9

Question 19

bleeding disorder 1

what can be mesured for evidence of clotting? What is this a process of?

Answer 19

D-dimers and Fibrin(ogen) degradation products

fibrinolysis - plasminogen to plasmin

Question 20

bleeding disorder 1

What would make you weary in thrombosis?

Answer 20

peeing out antithrombin due to a damaged glomerulus.

Question 21

what bleeding disorder is known as “clotting to death and bleeding to death at the same time?”

Answer 21

DIC, you’re clotting and running out of clotting factors. DIC can lead to liver failure.

Question 22

Why is vitmanin K important for coagulation and what does it have to do with bile obstruction?

Answer 22

Vitamin K is responsible for creating the activation site on coagulation factors.

vitamin K is fat soluble. The bile emulsifies fats. without fat, there can exist a vitamin K deficiency.

Question 23

What happens during thromboembolic disease?

Answer 23

pro-coagulant mechanisms overwhlem anticoagulant mechanisms and can cause vessel obstruction, poor or no perfusion and limb or organ dysfunction

Question 24

What are some primary and secondary ways to evaluate hemostasis?

Answer 24

primary: platelet count on a blood slide and bleeding time

Secondary: checking APTT and PT time, quantifying fibrinogen and vWF.

not mentioned is ACT (Activated clotting time) that is an old test that is no longer used.

Question 25

What are some clinical signs of a hemostasis disorder?

Answer 25

petechial (vascular and platelet abnormalities) and large hemorrahages (coagulation)

hemarthrosis is blood in the joints

Question 26

What are some acquired causes for vascular disease? what would lab results look like?

Answer 26

vasculitis, cushings, scurvy

mainly normal. prolonged bleeding and normal to decreased platelet count

coag tests would be normal

Question 27

You are looking at lab results for a hemostasis disorder. all coagulation tests are normal. there is prolonged bleeding and the ACT is slightly prolonged (can be normal to prolonged in current example). What may be the problem?

Answer 27

thrombocytopenia. these test don’t test for platelets, just the coagulation cascade. things are normal but something is not functioning.

Question 28

What breeds are susceptible to type I vWF?

Answer 28

doberman pinscher
welsh corgi
german sheperd
golden retriever
poodle

Question 29

What breeds are susceptible to type II vWF?

Answer 29

german shorthair pointer

Question 30

What breeds are susceptible to type III vWF?

Answer 30

scottish terrier, shetland sheepdog, chesapeake bay retriever

Question 31

What tests are normal for a vitamin k antagonism/ deficiency?

Answer 31

bleeding time, quantitative fibrinogen, and vWF

coagulation tests are prolonged

Question 32

DIC is a nonspecific response to many things like…? How does DIC present on lab results?

Answer 32

extensive tissue damage: heat stroke, pancreatitis, sever hypoxia
endotoxemia/septicemia
IMHA
Neolpasia (progoagulant proteins)
vascular disease
& more!

everything prolonged… every time.