Bleeding DIsorders Flashcards
In general, how do the clinical features of platalet bleeding and factor bleeding differ?
platelet: superficial bleeding (petechiae), spontaneous
factor: deep (joints), big bleeds, usually trauma
What is the most common hereditary bleeding disorder?
von willebrand disease
What’s the inheritance pattern for vWD?
autosomal dominant
Why does vWD vary in severity
because there are three types: one you just have decreased vWF, one you have abnormal vWF and the last one ou have no vWF
What cells make vWF>
megakaryocytes and endothelial cells
What does vWF do?
it esstneially glues platelets to subendothelium - gets the first layer of the clot on
WHat factor is carried by vWF so it doesn’t degrade?
factor VIII
What sort of bleeding will patient with vWD present with?
mucosal bleeding: nose bleeds, heavy menses, bruising, excessive bleeding after dental extractions
Why can you also get deep joint bleeding in really severe cases of vWD?
because it leads to a secondary factor 8 deficiency
What will the following lab tests show in vWD?
bleeding time? PTT? INR?
bleedint time prolonged PTT prolonged (corrects with mixing study) INR normal because it measure the extrinsic pathway only
If you do a platelet aggregation study, with what reagenet will you see it’s abnormal for vWD?
with ristocetin, which makes your platelets express GP Ib
It should make your platelets aggregate unless you odn’t have the vWF for the GPib to bind to
What’s the treatment for vWD?
DDAVP - which raises VIII and vWF levels if you have the tye where it’s just decreased
Cryoprecipitate (which containes VIII and vWF) if you don’t have any or you rhave abnormal
Facotr VIII - but avoid that whenever possible because patient can make antibodies to it eventually
What’s the most common FACTOR deficiency?
hemophilia A
WHat’s the interitance pattenr for the hemophilias?
x-linked recessive (so most cases are in boys, women are carriers)
How many cases of hemophilias are from raondom mutations?
30%
What factor is decreased in hemophilia A?
factor VIII
What sort of bleeding will hemophilia A patients present with?
deep joint bleeding that can be disfiguring over time
prolonged bleeding after dental work
rarely, mucosal hemorrhage (can be fatal)
What will the following labs show in Hemophilia A:
INR? TT? platelet count? bleeding time? PTT?
INR normal
TT normal
platelet count normal
bleeding time normal (remembe rit only looks at platelets)
PTT prolonged (corrects with mixing study)
What’s the treatment for hemophiliaA?
DDAVP - can increase VIII
Factor VIII - only when absolutely necessary
What factor is decreased in hemophilia B?
factor IX
Which is more common: a or b?
A is much more common (but still super rare)
What hereitary platelet disorder stems from abnormal GP Ib?
Bernard Soulier Syndrome