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34 Cards in this Set
- Front
- Back
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most common antigen to cause immune thrombocytopenic purpura
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GpIIb/IIIa receptor
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virchow's triad
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1. stasis
2. endothelial injury 3. hypercoagulable state |
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activated protein C acts on which clotting factors?
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factor VIIIa
factor Va |
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antithrombin acts on which clotting factors?
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thrombin (IIa)
factor Xa |
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how does heparin induced thrombocytopenia occur
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HIT type 2
heparin binds platelet factor 4 (PL4) and renders it immunogenic. antibodies form against PL4 and bind platelets. white, platelet rich clot forms (thrombosis), and thrombocytopenia occurs. |
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tissue factor pathway inhibitor acts on which clotting factors?
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thromboplastin - VIIa complex
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what is neonatal purpura fulminans?
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newborns presenting with purpura all over their body because they have a deficiency of protein C and protein S
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what is warfarin skin necrosis?
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out of the vitamin K dependent serine proteases(II, VII, IX, X, protein C, protein S), protein C has the shortest half life. This means that its levels drop first, resulting in intial HYPERcoagulability with initiation of warfarin treatment. thrombi form in the skin, and warfarin skin necrosis occurs
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what are the vitamin K dependent serine proteases in the clotting cascade?
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II, VII, IX, and X.
protein C and protein S |
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try to name 9 very common acquired risk factors for thrombosis
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1. Pregnancy (esp. postpartum)
2. Immobilization 3. Obesity 4. Advanced age 5. Estrogen use 6. Trauma 7. Postoperative state 8. Malignancy 9. Heparin-induced thrombocytopenia |
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how does factor V leiden cause a hypercoagulable state?
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it is APC resistant.
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most common inherited coagulation risk factor
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factor V leiden
factor five - 5% (U.S. caucasians) |
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second most common inherited coagulation risk factor
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prothrombin 20210
factor two - 2% (U.S. caucasians) |
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who has the worst thrombophilia:
1. factor V leiden heterozygote 2. antithrombin deficiency 3. factor V leiden homozygote |
1. factor V leiden homozygote. 18x
2. antithrombin deficiency 10-20x 3. factor V leiden 3x |
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what is the worst inherited coagulation risk factor that is compatible with life?
at age 60, what is these people's risk of developing thrombi? |
antithrombin deficiency
(heterozygous!) 60% at age 60. this shows that |
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how are people tested for factor V leiden?
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APC susceptibility test.
perform a clotting assay with and without APC added. APC should increase time to clot. If it doesn't increase time to clot as much as it should, then then they have APC resistance. If the patient has a positive test for APC resistance, they then have a genetic test (PCR) to prove that they have factgor V Leiden. This is important to know zygosity (3x vs 18x...) |
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how are people tested for prothrombin 20210?
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genetic test (PCR)
there is no screening test available |
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in what parts of the world are prothrombin 20210 and factor V leiden prominent?
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prothrombin 20210 - france, spain, portugal
factor V leiden - scandinavia |
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what problems do patients with too much factor VIII have?
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hypercoagulability
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why can't you test people for factor VIII excess in the hospital?
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it's an acute phase protein and will be physiologically elevated with stress
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what are several causes of acquired protein C or protein S deficiency?
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-warfarin treatment
-vitamin K deficiency -liver disease -trauma (consumption) -surgery (consumption) -DIC (consumption) -lupus anticoagulant S only -proteinuria -estrogen -pregnancy |
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what is lupus anticoagulant's effect in vitro and in vivo?
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lupus anticoagulant is an IgG autoantibody!
in vitro - binds phospholipids so increases PT and PTT in vivo - binds to endothelium and causes coagulation |
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name a few things that can cause an acquired antithrombin deficiency
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1. estrogen?
2. pregnancy? 3. DIC 4. liver dysfunction 5. recent surgery 6. recent thrombosis 7. heparin 8. proteinuria |
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what are two things that can cause antiphospholipid syndrome?
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1. anticardiolpin antibody
2. lupus anticoagulant |
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if you suspect lupus anticoagulant, what tests can you order?
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1. no correction by mixing study.
2. clotting time improves upon addition of more phospholipid |
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if you suspect anticardiolipin antibodies, what can you do?
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ELISA test
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do antiphospholipid syndromes cause venous or arterial thrombosis?
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they cause both
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patient has had 3 consecutive abortions before 10th week of gestation and thromboses. what is likely problem?
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antiphospholipid syndrome
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how is hyperhomocysteinemia treated?
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vitamin B12
folate B6 these increase the number of methyl groups going to regenerate methionine from hcy |
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what are 2 things that can cause both arterial and venous thromboses?
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1. antiphospholipid syndromes
2. hyperhomcysteiemia |
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what are some things that can cause hyperhomocysteinemia?
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1. stress (acute phase protein)
2. B12, folate, B6 deficiency 3. renal failure 4. hypothyroidism 5. methotrexate, phenytoin, theophylline 6. malignancy no idea why |
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what drug interferes with lupus anticoagulant tests?
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heparin
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what drug decreases protein c and protein S?
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warfarin
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what drug interferes with antithrombin functional tests?
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heparin
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