Step I clinical presentation

[GiJoe]

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whats the difference btwn Vonwillerbrand's disease and Glanzmann's thrombathenia and bernard soulier's disese in regards to clinical presentation? VW Dz is a problem with platlets trying to bind damaged subendothelial collagen, while bernard soulier is a defect in platelet adhesion and huge platelets. Glanzmann's is a defect in platelet aggregation. To me, all these patients would have an increased bleeding time... how do i tell them apart????

 

[tega]

there should be extra info

i.e for vw ptt (binds viii) may be included.....and for glanzmann and soulier, other info may be included to differentiate both....if not, both will not be in the choices....

Just as long as u know the exact mechanism for each of them u should be able to determine the correct answer

 

[fernj1975]

In Vonwillerbrand's disease you will have an increase in Ptt, Pt and bleeding time where as in Glanzmann's thrombathenia and bernard soulier you will only have increased bleeding time since its a platelet problem. Vonvillebrand will increase bleeding time because its required for the binding of platelets to the exposed endothelium, and it will increase Ptt time because its involve in the clotting cascade (I believe its factor VIII, but dont quote me).

 

[mpp]

Yes, vWF binds and stabilizes Factor VIII, so in vWF disease you get prolonged PTT. PT would be normal in all three. You can't tell Glanzman and Bernard Soulier apart just by those tests. Bernard Soulier has extra large platelets and is an adhesion disorder (like vWF) while Glanzman is an aggregation disorder.

How to remember it all:

B comes before G and adhesion comes before aggregation (both alphabetically and the steps are in that order).

vWF - well, that's on endothelium so it involves adhesion. Factor VIII since vWF has I-I-I letters = VIII (or just know it's the same factor in hemophilia A).

 

[GiJoe]

i thought PT was only increased in vit K def, and DIC. are you sure you see an increase in PT in VW disease?

 

[GiJoe]

Yes, vWF binds and stabilizes Factor VIII, so in vWF disease you get prolonged PTT. PT would be normal in all three. You can't tell Glanzman and Bernard Soulier apart just by those tests. Bernard Soulier has extra large platelets and is an adhesion disorder (like vWF) while Glanzman is an aggregation disorder.

How to remember it all:

B comes before G and adhesion comes before aggregation (both alphabetically and the steps are in that order).

vWF - well, that's on endothelium so it involves adhesion. Factor VIII since vWF has I-I-I letters = VIII (or just know it's the same factor in hemophilia A).

SWEET thanks man