Secondary hemostasis and related disorders Flashcards
Where is factor VIII produced?
Endothelial cells of liver sinusoids
How do disorders of secondary hemostasis present?
Deep tissue bleeding - rebleeding after surgical procedures, deep bleeding into muscles and joints, etc.
What is required for the activation of secondary hemostasis?
Exposure of coagulation factors to either subendothelial collagen (intrinsic pathway) or tissue factor (extrinsic)
Phospholipid surfaces of platelets
Calcium - released from platelet dense granules
Hemophilia A pathophys
Genetic deficiency (or de novo) of factor VIII leads to deep bleeding
Inheritance of Hemophilia A
X linked, but can be a de Novo mutation
Lab findings in Hemophilia A
Increased PTT, normal PT
Normal bleeding time/platelets
Treatment of Hemophilia A
Recombinant factor VIII
Hemophilia B (Christmas disease) patho phys
Genetic factor IX deficiency
What is the most common inherited coagulation disorder?
Von willibrand disease
Von Willibrand disease pathophys
Von Willibrand factor normally stabilizes factor VIII.
Genetic deficiency of vWF leads to decreased platelet adhesion as well has abnormal intrinsic pathway
Von Willibrand disease inheritance
Multiple forms but usually AD
Lab findings in Von Willibrand disease
Increased bleeding time, increased PTT, normal PT
Abnormal risocetin test
What is the risocetin test?
Risocetin induces vWF to bind to GPIb. If either of these are abnormal/decreased then the test will be abnormal
treatment of von willibrand disease
desmopressin (ADH) -induces endothelial cells to release vWF from Weibel-Palade bodies
Coagulation factor inhibitor disease pathophys
Antibody produced against coagulation factor, most commonly factor VIII
Lab findings will be similar to Hemophilia A, however will not correct when mixing with normal plasma (whereas hemophilia A will)
