19 - Inherited Clotting Disorders Flashcards
where is vWF synthesized?
endothelial cells and megakaryocytes
what factor does vWF bind to start clot formation?
FVII
intrinsic and extrinsic “tenase”
intrinsic - IXa and VIIIa
extrinsic - TF-VIIa
prothrombinase
Xa-Va
defects in primary hemostasis present how clinically?
mucocutaneous bleeding (petechiae, epistaxis, menorrhagia, etc) inc bleeding after aspirin or NSAIDs inc intraop/postop bleeding
defects in secondary hemostasis present how clinically?
deep bleeding - hemarthrosis, soft tissue/ muscle hematomas, ecchymoses
increased surgical bleeding
mucosal, GI, GU bleeding
types of von willebrand disease
type 1 - heterozygous, partial deficiency
type 2 - dysfunctional vWF, several subtypes
type 3 - homozygous, severe deficiency
tx for von willebrand dz
DDAVP (synthetic analog of vasopressin) - causes inc release of vWF. need to test for response
plasma derived F.VIII products
antifibrinolytic agents (aminocaproic acid, tranexamic acid) - good for mucosal bleeding, c/i for hematuria
which is the most common factor that is deficient in hemophilia A
VIII
inheritance of hemophilia A
x-linked recessive but up to 1/3 are spontaneous mutation
hemophilia is a disorder of (primary/secondary) hemostasis
secondary
what severity group are most hemophiliacs?
severe (90%)
tx for hemophilia A
recombinant F.VIII product
DDAVP for milder
anti fibrinolytics (aminocaproic acid, tranexemic acid)
long term sequelae of hemophilia A
inhibitor development - Ab react to F.VIII from repeated exposure and minimal host production
target joints - hemorrhages cause damage over time
hemophilia B is a deficiency in what factor?
F.IX
