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14 Cards in this Set
- Front
- Back
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How common is von Willebrand's disease?
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Most common congenital bleeding disorder (1/100 to 1/1000)
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What does vWF do?
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Links platelets to site of subendothelial injury
Intravascular carrier protein for factor VIII |
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What is vWF's role in TTP?
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In TTP, there is a deficiency of ADAMTS13, which normally cleaves vWF before it gets to big. Without as much cleavage, extra large vWF forms and binds to platelets. When it eventually gets cleaved, there is a large vWF-platelet thrombus floating around that can embolize and cause little ischemic events
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Where is vWF made?
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The endothelium
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How does vWF aid in platelet aggregation?
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When exposed, binds to Gp-1b on platelets to cause them to bind to the subendothelial injury location
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What are the bleeding symptoms in vWD?
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Epistaxis (nosebleed)
Easy bruisability Menorrhagia Mucosal bleeding Immediate bleeding post dental extraction Postpartum hemorrhage (rarely) spontaneous hemarthrosis (really only in severely deficient patients) |
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What are some of the lab tests for vWD?
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Factor VIII activity assay (low)
von Willebrand antigen assay (immune detection of vWF levels in plasma) Ristocetin cofactor assay (vWF functional activity assay) vWF multimer analysis |
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What are the broad types of vWD?
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Type 1 - partial quantitative deficiency
Type 2 - qualitative functional abnormality Type 3 - Complete deficiency |
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What are the subtypes of type 2 vWD?
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2A - decreased vWF-dependent platelet adhesion (low ristocetin response); selective deficiency of high-molecular-weight multimers
2B - increased affinity for platelet Gp-1b (increased ristocetin response) 2M - same as 2A but without the selective deficiency 2N - decreased binding affinity for FVIII |
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Describe type 3 vWD.
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Nearly complete deficiency of vWF
FVIII level 5% Both platelet-type immediate bleeding and hemophilic-type intramuscular and articular bleeding Could be mistaken for classical hemophilia Autosomal recessive |
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What is DDAVP?
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Synthetic vasopressin analogue that causes release of FVIII and vWF into circulation from endothelial stores
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What is DDAVP used to treat?
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FVIII deficient patients (although need FVIII > 5%)
Type I and IIA vWD |
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What is good and bad about FFP?
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Fresh frozen plasma
Good: replaces all clotting factors Bad: need a whole lot of it in common coagulation factor deficiencies |
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What factors does cryoprecipitate replace?
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FVIII
fibrinogen vWF FXIII |
