Hemostasis 2

Question 1

common pathway steps

Answer 1

activated X (plus Va and PL and Ca) activate prothrombin to thrombin aka 2a. convert fibrinogen to fibrin (1a) and you get a crosslinked stable fibrin clot

Question 2

lab evaluation of common pathway

Answer 2

PT and PTT in conjunction

Question 3

thrombin: functions

Answer 3

converts fibrinogen to fibrin. activates factor 13 for stabilizing/crosslinking fibrin clot. activates factor 11, 8 (intrinsic) and 5 (common). activates platelets directly

Question 4

what does PTT assess

Answer 4

intrinsic pathway: 12, 11, 9 and 8

Question 5

PT assess?

Answer 5

extrinsic pathway: factor 7

Question 6

PTT and PT both assess

Answer 6

the common pathway: 10 5 2 and 1

Question 7

PT: what do you put in the test tube?

Answer 7

patient plasma, Ca and PL and tissue factor = forces it to the extrinsic pathway

Question 8

PTT: what do you put in the tube

Answer 8

patient plasma, Ca, PL and negatively charged surface activator which activates XII = intrinsic pathway

Question 9

INR

Answer 9

PT (extrinsic) converted to a ratio aka international normalization ratio

Question 10

fibrinolysis

Answer 10

normal process that melts clots aa breaks down or lyses the clot

Question 11

fibrinolysis: main steps

Answer 11

plasminogen converted into plasmin, breaks fibrin down into degradation products including D dimers

Question 12

fibrinolysis and PT/PTT?

Answer 12

not reflected by PT/INR or PTT: only measures how long it takes for clot to form

Question 13

so how would you measure fibrinolysis

Answer 13

fibrinogen. d dimers. other special tests

Question 14

categories of bleeding disorders (3)

Answer 14

platelet disorders. von willebrand diasease. (these two are primary hemostatic disorders. factor deficiencies (secondary hemostatic disorder, aka coagulation factor problem)

Question 15

causes of acquired bleeding disorders (9)

Answer 15

drugs/medications. alcohol. liver/kidney failure. cardiopulmonary bypass. marrow failure/hematologic disorders. acidosis/hypothermia/hypocalcemia. disseminated intravascular coagulopathy DIC. hyperfibrinolysis. vascular/collagen disorders.

Question 16

effects of primary vs. secondary hemostatic defects

Answer 16

primary (VW disease, platelet dysfunction) = muco cutaneous bleeding like nosebleeds, heavy periods, bleeding into skin. secondary (hemophilia) = deep tissue hematomas, bleeding into joints and muscles

Question 17

4 examples of cutaneous bleeding

Answer 17

petechia, purpura, ecchymosis, hematoma