thrombic disorders Flashcards

1
Q

What are the three major risk factors for thrombosis?

A

1) endothelial damage (HTN, cholesterol, smoking)
2) stasis (bed rest, varicose veins, heart problems)
3) hypercoagulability ( trauma/surg, delivery, disorder)

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2
Q

Which labs should you order if you suspect a thrombotic disorder?

A

1) INR
2) PTT
3) TT

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3
Q

What is the effect of the genetic mutation common in Caucasians leading to factor five leiden disorder?

A

factor V is abnormal and cannot be cleaved by protein C and thus cannot be “turned off”

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4
Q

How would you treat a patient with factor V leiden disorder?

A

no clots- no tx
1 clot- temporary anticoag
2+ clots- long term anticoag

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5
Q

What is the natural role of AT III and how do we take advantage of it pharmacologically?

A

binds and inhibits activated factors 2, 7, 9, 10, and 11,

heparin potentiates it to prevent coagulation

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6
Q

What are the clot risk probabilities for a heterozygote and homozygote with AT III def?

A
homo= no survival 
hetero= half of ppl with mutation will develop clots
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7
Q

How do you treat ATIII def?

A

give antithrombin concentrates (heparin won’t work!)

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8
Q

What are the three roles of protein C?

A

1) anticoagulant - inactivate Va and VIIIa
2) fibrinolytic (promote tPA)
3) anti-inflammatory (decrease cytokines)

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9
Q

What are the major complications of a mutation producing decreased levels or a mutated form of protein C?

A

Warfarin induced skin necrosis (coumadin inhibits proteins C and S before II, VII, IX, and X)
purpura fulminans - thrombus + vascular injury

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10
Q

What is protein S?

A

endothelial cell receptor for protein C

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11
Q

What is the effect of the factor II (prothrombin) gene mutation?

A

too much (functionally normal) prothrombin

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12
Q

What is the natural role of homocysteine?

A

converts precursors into THF (tetrahydrofolate)

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13
Q

What is homocysteinuria?

A

rare metabolic deficiency in tran-sulfuration enzyme

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14
Q

Why do increased levels of homocysteine in the blood and/or urine cause increased thrombi and premature atherosclerosis?

A

toxic to the endothelium (production of ROS) and interferes with NO, a natural vasodilator and antithrombotic

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15
Q

What vitamin deficiency is homocysteinemia associated with?

A

B12/folate

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16
Q

What is the only acquired thrombotic disorder we have discussed thus far?

A

antiphospholipid antibody syndrome

17
Q

How would you look for antiphospholipid antibody production?

A

1) PTT -prolonged
2) PTT mixing study- not corrected= inhibitor present in blood
3) “fancy tests”
* note normal PTT tests do not rule out Ab production

18
Q

What symptoms would you see in an adult with autoimmune problems whom you suspected of having antiphospholipid antibody syndrome?

A
recurrent thromboses
recurrent spontaneous abortions
increased risk of stroke
pulmonary HTN
renal failure
19
Q

Why would an INR be unhelpful in diagnosing antiphospholipid antibody syndrome?

A

in vivo antiphospholipid Ab promote coag

in vitro antiphospholipid Ab inhibit coag