Pathoma: 2a hemostatsis and related disorders

Question 1

What is the goal of 2a hemostasis?

Answer 1

to stabilize the platelet plug

Question 2

How does 2a hemostasis achieve its end goal?

Answer 2

via the coagulation cascade

Question 3

What is the receptor for platelet aggregation?

Answer 3

GPIIb/IIIa

Question 4

What molecule links the platelets via GPIIb/IIIa?

Answer 4

fibrin

Question 5

What is the end product of the coagulation cascade?

Answer 5

thrombin

Question 6

What does thrombin do?

Answer 6

it converts fibrinogen to fibrin

Question 7

What gets crosslinked to generate a stable platelet plug?

Answer 7

fibrin

Question 8

What 3 things does activation require?

Answer 8

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

Question 9

Where does the calcium come from?

Answer 9

dense platelet granules

Question 10

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

Answer 10

factor abnormalities

Question 11

______ is the major clinical feature of 2a hemostasis.

Answer 11

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

Question 12

In 1a hemostasis, the primary problem is ______.

Answer 12

superficial bleeding (into mucosa and

Question 13

What is the PT test?

Answer 13

a measure of extrinsic and common factors

Question 14

What is the PTT test?

Answer 14

a measure of intrinsic and common factors

Question 15

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

Answer 15

12, 11, 9, 8, 10

Question 16

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

Answer 16

7, 10

Question 17

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

Answer 17

10, 5, 2, 1

Question 18

What activates factor 12 (the intrinsic pathway)?

Answer 18

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

Question 19

What activates factor 7 (the extrinsic pathway)?

Answer 19

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

Question 20

Which test is better for measuring heparin?

Answer 20

PTT

* PTT and HEP are both 3 letters

Question 21

Which test is better for measuring warfarin/Coumadin?

Answer 21

PT

Question 22

What is hemophilia A?

Answer 22

an X-linked defect of factor VIII (8)

* hemophilia AAAAA-eight

Question 23

How do hemophilia A pts present?

Answer 23

deep tissue, joint, and post-surg bleeding

Question 24

The clinical severity of hemophilia A depends on _____.

Answer 24

the degree of deficiency

Question 25

Hemophilia A lab results?

Answer 25

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

Question 26

What is the treatment for Hemophilia A?

Answer 26

give recombinant factor VIII

Question 27

What is Hemophilia B?

Answer 27

a genetic factor IX (9) deficiency

Question 28

What is another name for Hemophilia B?

Answer 28

Christmas disease

Question 29

What is a coagulation factor inhibitor?

Answer 29

an autoantibody against a coagulation factor, impairing its function

Question 30

Which factor is commonly targeted by coagulation factor inhibitors?

Answer 30

factor VIII (8)

Question 31

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

Answer 31

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 32

What is Von Willebrand disease?

Answer 32

the most common inherited coagulation disorder- deficiency of vWF

Question 33

What is the most common subtype of vW disease?

Answer 33

auto. dominant; decreased vWF levels

Question 34

How does a vW Disease pt present?

Answer 34

mild mucosal and skin bleeding

Question 35

What does low vWF cause?

Answer 35

impaired platelet adhesion

Question 36

What are the lab findings in vW Disease?

Answer 36

increased bleeding time increased PTT normal PT abnormal ristocetin test

Question 37

Why is the PTT increased in vW Disease?

Answer 37

vWF stabilizes factor VIII (8)

Question 38

What is the ristocetin test?

Answer 38

ristocetin given to platelets makes them aggregate- if there's no vWF, they won't clump

Question 39

What is the tx for vW Disease ?

Answer 39

desmopressin

Question 40

How does desmopressin work?

Answer 40

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

Question 41

What is Vitamin K deficiency?

Answer 41

disrupted coagulation

Question 42

Why is Vitamin K so important for coagulation?

Answer 42

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

Question 43

Vitamin K is activated by ____ in the ____.

Answer 43

epoxide reductase; liver

Question 44

_____ blocks epoxide reductase.

Answer 44

Coumadin

Question 45

When can vitamin K deficiency present?

Answer 45

1. newborns 2. long-term Abx 3. malabsorption (esp fat) 4. liver failure

Question 46

Why does long term Abx therapy cause Vitamin K deficiencies?

Answer 46

vit K is synthesized by normal gut flora

Question 47

How is vitamin K deficiency prevented in newborns?

Answer 47

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

Question 48

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

Answer 48

PT

Question 49

What happens when large volume transfusions are given?

Answer 49

coagulation factors are diluted, leading to deficiencies