Secondary Hemostasis Flashcards
What does secondary hemostasis do?
Coagulation cascade makes thrombin which convert fibrinogen to fibrin.
What triggers the intrinsic pathway?
Tissue thromboplastin activates factor XII
What triggers the extrinsic pathway?
Subendothelial collagen activates factor VII
what does activation require?
activating substance
phospholipid surface (platelets)
calcium
Features of disorder?
Deep tissue bleeding, rebleeding
Abnormal PT, PTT
What causes hemophilia A?
Factor VIII deficiency
X linked recessive
can be de novo
Lab findings of Hemophilia A?
increased PTT
normal PT
normal platelet and bleeding time
What causes hemophilia B?
Factor IX deficiency
What is coagulation factor inhibitor?
an acquired antibody against a coagulation factor
PTT does not correct when mixed with normal plasma. The hemophilia disorders do correct when mixed with normal plasma.
What is the most common inherited coagulation disorder?
Von Willebrand disease.
genetic vWF deficiency
What are the clinical and laboratory findings of Von Willebrand disease?
mild mucosal and skin bleeding increased bleeding time increased PTT normal PT decreased VIII half life (stabilized by vWF) Abnormal risotecin
What is the treatment of Von Willebrand disease?
desmopressin (increases vWF release from WP bodies)
What gamma carboxylates factors II VII IX X and proteins C and S?
vitamin K (activated by liver epoxide reductase)
What are two “other” causes of abnormal secondary hemostasis?
Liver Failure
Large Volume transfusions
