Flashcards in Fiser: Hematology Deck (69)
what are three main functions of thrombin?
1. converts fibrinogen to fibrin
2. activates factor V and VIII
3. Activates platelets
what are three factors that are involved in normal anticoagulation?
antithrombin III, protein C and protein S
what are the only two factors not synthesized in the liver?
factor VIII and vWF (made in the endothelium)
function of protein C
degrades factors V and VIII and fibrinogen
function of protein S
cofactor of protein C
what are the vitamin K dependent factors?
II, VII, IX, X and poteins C and S
whats the normal half life of PRBCs and platelets?
PRBCs = 120 days, Plat = 7 days
functions of prostacyclin? where does it come from?
1. decreases platelet aggregation and promotes vasodilation
2. increases cAMP in platelets
*antagonist to TXA2, comes from endothelium
functions of Thromboxane? where does it come from?
1. increases platelet aggregation and promotes vasoconstriction
2. triggers release of calcium in platelets to cause platelet-platelet binding and platelet-collagen binding
* from platelets
what is cryoprecipitate?
contains highest concentration of vWF-VIII, has high levels fibrinogen, used in von willebrands disease and hemophilia A (factor VIII deficiency)
what does ddavp do?
causes the release of VIII and vWF
what is the best measurement for liver synthetic function?
PT (prothrombin time)
what does PT (prothrombin time) measure?
II, V, VII, and X, fibrinogen, (best for liver synthetic function)
what does the PTT measure? ( partial thromboplastin tme)
measures most factors EXCEPT VII and XIII so does not pick up factor VII deficiency!
what is the most common congenital bleeding disorder?
von Willbrand's disease
what are the different types and inheritance patterns of von willebrand's disease?
type I: AD, MC, reduced quantity of vWF, mild symptoms
type II:AD, defect in vWF molecule itself, vWF doesnt wok well
type III:AR, most severe bleeding but rare, complete vWF deficiency (DDAVP does not work here!- give cryo)
what is the function of vonwillbrands factor?
link Gp1b receptor on platelets to collagen
what do you see on coag profile in vW disease?
PT normal, PTT can be normal or abnormal, bleeding time is long (ristocetin test)
what is hemophilia A and inheritance?
factor VIII deficiency, sex linked recessive
what coag profile do you see in hemophilia A?
prolonged PTT, normal PT (factor VIII deficiency)
tx of hemophilia A bleeding? (hemarthrosis, epistaxis, ICH)
factor VIII concentrate or cryoprecipitate)
What is hemophilia B? inheritance?
factor IX deficiency, sex linked (aka christmas disease)
what coag profile do you see in hemophilia B?
prolonged PTT, normal PT (factor IX deficiency)
tx for hemophilia B bleeding?
FFP or recombinant factor IX
what are the key functions of antithrombin III?
binds and inhibits thrombin
inhibits factors IX, X and XI
what is the MOA of heparin?
activates antithrombin III up to 1000x the normal activity, neutralizes factors Xa and IIa
coag profile of factor VII deficiency?
prolonged PT and normal PTT
what is Glanzmann's thrombocytopenia?
GIIb/IIIa receptor deficiency, thus platelets cant bind to eachother, tx = platelets
what is benard soulier disease?
Gp1b receptor deficiency on platelets, thus cannot bind to collagen, tx = platelets