Clotting GK

Question 1

Platelets and clotting factors circulate normally in an _________ form.

Answer 1

Platelets and clotting factors circulate normally in an inactive form.

Question 2

Vascular injury disrupts endothelium and leads to what 3 things?

Answer 2

1. Vascular spasm
2. Platelet adhesion mediated by Von Willebrand factor
3. Coagulation cascade

Question 3

What does PT represent?

Answer 3

time in seconds for plasma to clot after addition of calcium and an activator of extrinsic pathway (thromboplastin)

Question 4

What leads to a prolonged PT?

Answer 4

Deficiencies or inhibitors of clotting factors within extrinsic or final common pathways

Question 5

Why was INR created?

Answer 5

PT results for identical patients vary with different labs

Question 6

What is INR?

Answer 6

mathematical conversion of patient’s PT compared to geometric mean of PT of at least 20 healthy subjects of males and females at THAT lab

Question 7

What does PTT (Partial Thromboplastin Time) measure?

Answer 7

integrity of intrinsic and final common pathways of coag cascade

Question 8

What does PTT represent?

Answer 8

time in seconds for patient’s plasma to clot after the addition of phospholipid, an intrinsic pathway activator- calcium

Question 9

if clotting times remain prolonged what should you think?

Answer 9

inhibitor

Question 10

if clotting times normalize or decrease to near-normal what should you think?

Answer 10

factor-deficiency

Question 11

What does PTT correct?

Answer 11

Factor DEFICIENCY of intrinsic pathway like factors VIII, IX, XI, or XII

Question 12

How can you determine which clotting factor is involved with an abnormal PTT?

Answer 12

clotting factor assay

Question 13

PTT stays prolonged with what?

Answer 13

an inhibitor: heparin, LMWH, AIH/Factor 8 inhibitor

Lupus anticoagulant

Question 14

What do you see in pts w/LAC (lupus anticoag)?prolonged PTT

Answer 14

prolonged baseline PTT

Seen more in young females

Question 15

When would you suspect LAC?

Answer 15

pt w/no bleeding hx

pt w/clot w/baseline prolonged PTT before Ant-coag was started

Question 16

What should you think if a PT corrects with normal PTT?

Answer 16

DEFICIENCY of factors II, VII, and X or fibrinogen (2, 7, 10)

Liver dz (prolonged PT)

Question 17

What should you think if PT is still prolonged with prolonged PTT?

Answer 17

Factor 5 inhibitor

Question 18

PT and PTT MIxing study:

deficiencies caused by what?

Answer 18

supratherapeutic warfarin or rat poison

Question 19

what inhibitors will you see in lymphoproliferative d/o or monoclonal protein d/o?

Answer 19

LAC

nonspecific factor inhibitors

Question 20

Pts with what 2 disorders can develop antibodies against self (have autoimmune characteristics)?

Answer 20

lymphoproliferative d/o

monoclonal protein d/o

Question 21

Warfarin:

What can supratherapeutic INR lead to?

Answer 21

elevated PTT

Question 22

every 1.0 increase of PT is what of PTT?

Answer 22

16-17 sec PTT

Question 23

3 MC reasons to use Warfarin

Answer 23

1) A-Fib INR 2-3
2) VTE INR 2-3
3) Mechanical valve replacement- INR 2.5-3.5

Question 24

Warfarin interferes with what factors and proteins?

Answer 24

factors VII, IX, X and proteins C & S

Question 25

Can you use warfarin in pregnancy?

Answer 25

No: Preggo X

Question 26

UFH inhibits which factors?

Answer 26

IIa (thrombin)

Xa

Question 27

UFH PK and risk

Answer 27

PK: large molecule: 30 units long and not well absorbed subcutaneously

risk of HIT

Question 28

What does LMWH inhibit?

Answer 28

More of Xa

some of IIa

Question 29

LMWH benefits

Answer 29

smaller so well absorbed subcutaneously

predictable 1/2 life

Ex: Enoxaparin, Dalteparin

Risk of HIT

Can give with preggos

Question 30

T/F: No need to draw blood tests to see if anticoag is therapeutic unless pt. is very obese or very thin

What would you draw if you had to?

Answer 30

TRUE

anti-factor Xa levels 3-4 hrs post LMWH administered

Question 31

synthetic pentasaccharide that inhibits factor Xa and binds to antithrombin III causing antithrombin III to go through conformational change inhibiting coag cascade

Half-life 17 hrs. long and NO reversal agent

Which med?

Answer 31

Fondaparinux

Question 32

Direct Xa inhibitors

Answer 32

Rivaroxaban

Apixaban

Question 33

ex of DOAC

Answer 33

dabigatran

Question 34

what are fondaparinux, rivaroxaban/apixaban and dabigatran used for?

Answer 34

A-fib & VTE

Question 35

What agents should be used to reverse overdose in the following meds?

1. Heparin
2. Enoxaparin
3. Pradaxa
4. Xarelto
5. Fondaparinux

Answer 35

1. Heparin: Protamine
2. Lovenox/Fragmin: Protamine
3. Pradaxa: Dialysis (if bleeding in brain) or Idarucizumab (if no bleeding)
4. Xarelto/Eliquis- PCC
5. Fondaparinux (Arixtra)- Novo 7, DDAVP

Question 36

RF for VTE & hypercoagulable state

Answer 36

stasis

recent trauma/surgery and hypercoagulable state

increased risk for venous thromboembolism (VTE)

CA (Trousseau’s syndrome)

pregnancy

smoking

estrogen

Question 37

Protein C & S along with antithrombin III deficiencies

Factor V Leiden mutation

Prothrombin gene mutation

Lupus anticoagulant

Hyperhomocysteinemia

Anticardiolipin antibody

Paroxysmal nocturnal hemoglobinuria

These are all…

Answer 37

hypercoagulable states

Question 38

what 3 things prevent overclotting?

Answer 38

Protein C, Protein S, and Antithrombin III

Question 39

Both are vitamin K dependent proteins

Both can be low in nephrotic syndrome

Answer 39

Protein C &S

Question 40

Can be low d/t liver disease, nephropathy or heparin

Mutations reduce levels or decrease its functional capacity

Answer 40

Antithrombin III deficiency