Coagulation

Question 1

what is the only place where clots should form

Answer 1

subendothelium

Question 2

what is vWF

Answer 2

Von Willebrand factor- rpotein tha binds to receptors on platelets, activating them = makes them sticky

Question 3

what is fibrinogen

Answer 3

Clotting factor that helps platelets stick together
forms a weak platelet plug if not activated into fibrin

Question 4

What factors are involved in primary coagulation

Answer 4

vWF
fibrinogen

Question 5

Fibrinogen is activated into fibrin in
1. primary coagulation
2. secondary coagulation

Answer 5

2

Question 6

___ is a cofactor in activation of most coag factors

Answer 6

Ca2+

Question 7

what organ produces coagulation factors

Answer 7

liver

Question 8

liver uses vit K to produce which coagulation factors

Answer 8

2, 7, 9, 10, protein C and S

Question 9

which coagulation pathway initiates the cascade

Answer 9

extrinsic

Question 10

describe how the extrinsic apthway initiates the coagulation cascade

Answer 10

factor 7 + TF –> activate factor 10
factor 10a combines with 5a and leads into common pathway
factor 2 is activated into thrombin, which then activates fibrinogen to fibrin

Question 11

which lab test is a test of the function of the extrinsic pathway

Answer 11

INR

Question 12

which lab test is a measure of the function of the intrinsic coagulation pathway

Answer 12

PTT

Question 13

describe the function of the intrinsic pathway in coagulation

Answer 13

amplifies the cascade
thrombin activates factor 11, which leads to activation of 8, 9 = amplifies cascade

Question 14

which factors are part of the intrinsic coagulation pathway

Answer 14

8, 9, 11, 12

Question 15

factor 7 is part of the _____ coagulation pathway

Answer 15

extrinsic

Question 16

deficiency of factors 8 and 9 results in

Answer 16

hemophilia A and B

Question 17

what does antithrombin act on

Answer 17

thrombin 2A and factor 10A

Question 18

what acts on factor 8 to stop clotting

Answer 18

protein C and S

Question 19

what dissolves the fibrin mesh

Answer 19

plasmin (activated from plasminogen by tPA)

Question 20

D dimer is a sign of

Answer 20

clot formation

Question 21

Heparins induce the effect of ____ to inhibit coagulation

Answer 21

antithrombin (inhibits factors 10, 2)

Question 22

what is a pro and con of UFH

Answer 22

pro: rapid reversal after stopping infusion
con: requires frequent PTT monitoring, IV only

Question 23

why is LMWH typically preferred to UFH

Answer 23

more predictable pharmacokin
no lab monitoring required routinely
only required AQ q12-24hrs

Question 24

what does warfarin inhibit to prevent clotting

Answer 24

vit K epoxide reductase in liver ( = less factor II, VII, IX, X, protein C and S)

Question 25

what is an umbrella term for abnormally large clots in venous system

Answer 25

venous thromboembolism

Question 26

what is Virchow's triad

Answer 26

stasis venous endothelial injury hypercoagulability

Question 27

what are some common sx of DVT

Answer 27

Sx: most commonly in legs - pain, heaviness, cramping, swelling, skin discoloration (red-blue hue) Physical exam signs: unilateral limb swelling (leg or arm), warmth, visibly distended veins

Question 28

T or F: the Well's Score is validated for DVTs in upper extremities

Answer 28

F use clinical judgement to categorize risk, then proceed to D dimer and ultrasound as usual

Question 29

Describe what would happen if the Well's criteria suggested unlikely DVT? what about likely?

Answer 29

unlikely = D-dimer as a rule out likely = ultrasound directly

Question 30

what is the test of choice for DVT

Answer 30

compression ultrasound

Question 31

in DVT, what is the proceedure if there is a + D dimer but negative US?

Answer 31

repeat US in 5-7 days to definitively rule out DVT

Question 32

what are some sx of PE?

Answer 32

Sx: sudden SOB, pleuritic chest pain (worse with deep breaths or coughing), hemoptysis (coughing up blood), syncope, sx DVT Wide variety of severity possible Common signs: tachycardia, tachypnea, hypotension, hypoxemia, distended neck veins Late signs: pulmonary friction rub, ↓ breathe sounds

Question 33

pleuritic chest pain that is worse with deep breaths or coughing could be a sign of ___

Answer 33

PE

Question 34

what is the approach to diagnosing a PE?

Answer 34

use well's score to assess probability high probability --> imaging low --> D dimer

Question 35

T or F: Well's score is valid for all patients

Answer 35

F- only valid in hemodynamically stable pts (BP >90)

Question 36

what is the gold standard for PE diagnostic imagine?

Answer 36

CTPA (CT pulm angio)

Question 37

what are some limitations of CPTA

Answer 37

high radiation dose, contrast risks in pregnancy, CKD, contrast allergies

Question 38

if a CTPA is CI, what can be used to dx PE instead?

Answer 38

VQ scan

Question 39

how does PE cause tachycardia and hypotension

Answer 39

R heart strain from sudden ↑ pulmonary artery pressure R heart = weak = fails under sudden pressure load = ↑ risk MI

Question 40

what should be part of initial assessment of sus VTE

Answer 40

ABCs signs of hemodynamic instability: hypoxemia, tachycardia, hypotension

Question 41

what are in and out of hospital tx options for hemodynamically stable VTE

Answer 41

in hospital: UF, LMWH outpt: DOACs or warfarin

Question 42

what could be used if anticoagulants are CI in VTE

Answer 42

inferior vena cava filter- prevents embolization from DVT to lungs (doesn't prevent clot formation)

Question 43

T or F: if the pt is at high probability of sus VTE, AC should be held until imaging to confirm

Answer 43

F- benefit of early tx > risk of incorrect dx

Question 44

how many months of AC should be done for 1st provoked clot with resolved RF? what if RFs are not resolved?

Answer 44

resolved = 3 mths (6 if massive) not resolved = AC until resolved

Question 45

how many months of AC should be done for 1st unprovoked clot?

Answer 45

>3mths, consider long term due to possible thrombophilia

Question 46

how many months of AC should be done for 2nd unprovoked clot?

Answer 46

lifelong coagulation (probable thrombophilia)

Question 47

how many months of AC should be done for 2nd provoked clot?

Answer 47

3-6mths

Question 48

list 3 types of acquired thrombophilias

Answer 48

surgery and trauma = strongest acquired risk malignancy autoimmune conditions medications (estrogen) pregnancy smoking obesity DM HPTN

Question 49

what are the 4 types of hereditary thrombophilias

Answer 49

protein C and S deficiency antithrombin deficiency Factor V leiden mutation (factor V resistant to inactivation) Prothrombin G2021A mutation (↑ prothrombin production)