Blood: 4.2: 2a hemostasis

Question 1

What does thrombin do?

Answer 1

it converts fibrinogen to fibrin

Question 2

What is the ristocetin test?

Answer 2

• ristocetin + platelets –> aggregation
• if there’s no vWF, they won’t clump

Question 3

In 1a hemostasis, the primary problem is ______.

Answer 3

superficial bleeding

Question 4

What test would check the effect of liver failure on coagulation?

Answer 4

PT

Question 5

______ and _______ are the major clinical feature of 2a hemostasis.

Answer 5

• Deep bleeding (into muscles and joints)
• rebleeding after surgery

Question 6

What is the PTT test?

Answer 6

• a measure of intrinsic and common pathways
  
  • PTT = more letters than PT, so it’s the LONGER pathway
  • 12, 11, 9, 8, 10, 5, 2, 1

Question 7

What is the most common subtype of vWF disease? What is the result?

Answer 7

• auto. dominant
• decreased vWF levels

Question 8

What is Vitamin K deficiency?

Answer 8

disrupted coagulation

Question 9

What does low vWF cause?

Answer 9

impaired platelet adhesion

Question 10

Why is Vitamin K so important for coagulation?

Answer 10

it’s necessary for gamma-carboxylation of factors 2, 7, 9, 10, C, and S

Question 11

Platelet activation requires calcium. Where does the calcium come from?

Answer 11

dense platelet granules

Question 12

How does desmopressin work?

Answer 12

• it increases vWF release from the Weibel-Palade bodies in endothelial cells
• * W for vWF, P for P-selectin

Question 13

The clinical severity of hemophilia A depends on _____.

Answer 13

the degree of deficiency

Question 14

Where does Vitamin K come from?

Answer 14

normal gut flora

Question 15

Platelets adhere using vWF and _____.

Answer 15

GPIb

Question 16

How do hemophilia A pts present?

Answer 16

• deep tissue, joint, and post-surg bleeding
  
  • these are classic s/s of a secondary hemostasis disorder

Question 17

Hemophilia A lab results?

Answer 17

• increased PTT
• normal PT
• decreased FVIII
• normal platelets
• normal bleeding time

Question 18

Which factor is most commonly targeted by coagulation factor inhibitors?

Answer 18

factor VIII (8)

Question 19

What gets cross-linked to generate a stable platelet plug?

Answer 19

fibrin

Question 20

Why does long term Abx therapy cause Vitamin K deficiencies?

Answer 20

• vit K is synthesized by normal gut flora
• loss of gut bacteria = loss of vitK

Question 21

What is the treatment for Hemophilia A?

Answer 21

• give recombinant factor VIII

Question 22

What is another name for Hemophilia B?

Answer 22

Christmas disease

Question 23

What molecule links the platelets via GPIIb/IIIa?

Answer 23

fibrinogen

Question 24

What happens when large volume transfusions are given?

Answer 24

coagulation factors are diluted, leading to deficiencies

Question 25

What is the PT test?

Answer 25

* a measure of extrinsic and common pathways * PT is SHORTER than PTT, so PT is less factors * factor 7, 10, 5, 2, 1

Question 26

Where are the coag. cascade factors produced?

Answer 26

in the liver

Question 27

\_\_\_\_\_ blocks epoxide reductase.

Answer 27

Warfarin/Coumadin

Question 28

What is hemophilia A?

Answer 28

* an X-linked recessive defect of factor VIII (8) * can be de-novo mutation * \* hemophilia AAAAA-eight

Question 29

In which pts can vitamin K deficiency present?

Answer 29

1. newborns 2. long-term Abx users 3. malabsorption (bc it's a fat soluble vitamin) 4. liver failure (less production of factors and they're not activated bc of loss of epoxide reductase)

Question 30

What is the goal of 2a hemostasis?

Answer 30

to stabilize the weak platelet plug

Question 31

What are the lab findings in vWF disease?

Answer 31

* increased bleeding time * increased PTT (bc vWF stabilizes factor VIII) * normal PT * abnormal ristocetin test

Question 32

What activates factor 12 (the intrinsic pathway)?

Answer 32

* subendothelial collagen (SEC) * \* PTT and SEC are both 3 letters

Question 33

What is Hemophilia B?

Answer 33

* a genetic factor IX (9) deficiency * resembles hemophilia A

Question 34

What is the order of the common pathway, starting at 10?

Answer 34

* 10, 5, 2, 1 * "1 x 2 x 5 = 10"

Question 35

What is a coagulation factor inhibitor? Which is most common?

Answer 35

* an acquired autoantibody against a coagulation factor, impairing its function * anti-FVIII (factor 8) most common

Question 36

What is the receptor for platelet aggregation?

Answer 36

GPIIb/IIIa

Question 37

Which test is better for measuring warfarin/Coumadin?

Answer 37

* PT/INR

Question 38

What 3 things does activation require?

Answer 38

1. exposure to an activating surface 2. phospholipid surface 3. calcium

Question 39

The goal of the coag. cascade is to produce factor \_\_\_\_.

Answer 39

X "produce a perfect 10"

Question 40

Why is the PTT increased in vWF Disease?

Answer 40

vWF stabilizes factor VIII (8)

Question 41

Vitamin K is activated by ____ in the \_\_\_\_.

Answer 41

* epoxide reductase * liver

Question 42

Activation requires a phospholipid surface. Where does this come from?

Answer 42

the surface of the platelets

Question 43

How does a pt with vWF disease present?

Answer 43

mild mucosal and skin bleeding

Question 44

Clinically, how can you tell the difference btw Hemophilia A and a coagulation factor inhibitor against factor VIII?

Answer 44

A **mixing study**: the **increased PTT can be corrected in Hemophilia A** by mixing pt's plasma with a normal plasma, but this **can't happen if an inhibitor is present**

Question 45

What is the order of the intrinsic pathway factors, ending at 10?

Answer 45

12 --\> 11 --\> 9 --\> 8 --\> 10

Question 46

In general, a disorder of 2a hemostasis is due to \_\_\_\_\_.

Answer 46

factor abnormalities

Question 47

How does 2a hemostasis achieve its end goal?

Answer 47

via the coagulation cascade

Question 48

What is Von Willebrand disease?

Answer 48

* a deficiency of vWF * the most common inherited coagulation disorder

Question 49

What activates factor 7 (the extrinsic pathway)?

Answer 49

* tissue thromboplastin (TT) * \* TT and PT are both 2 letters

Question 50

What is the order of the intrinsic pathway factors, ending at 10?

Answer 50

7, 10

Question 51

How is vitamin K deficiency prevented in newborns?

Answer 51

they're all given a prophylactic vitamin K shot at birth

Question 52

What is the end product of the coagulation cascade?

Answer 52

thrombin

Question 53

Which test is better for measuring heparin?

Answer 53

* PTT * \* PTT and HEP are both 3 letters

Question 54

What is the tx for vW Disease ?

Answer 54

desmopressin