coagulation and platelet disorders Flashcards
what is coagulation initiated by?
cell injury, exposure of blood to collagen
what clotting factors are:
made by the liver
all clotting factors are what in the blood?
enzymes, in inactive forms
activation of clotting factors is what?
a cascade
thrombin leads to what?
fibrinogen
fibrinogen leads to what?
fibbing molecules (bind together into long fibrinous strands)
what is thromboembolic disease?
the abnormal formation of blood clots (95% of heart attacks)`
what are the factors of thromboembolic disease?
triad of Virchow
what are the triads of Virchow?
-loss of vessel wall integrity(endothelial injury, plaque formation)
-change in the blood constituents which increase the probability of coagulation (platelets, clotting factors, viscosity)
-abnormalities in blood flow (decreased flow rate and turbulent flow in arteries-eddies)
what are the treatments for thromboembolic disease?
heparin
Coumadin
break down existing clots:
-streptokinase
-urokinase
-TPA
-asprin
what does heparin do?
inhibits the formation of thrombin with antithrombin
what does Coumadin do?
decreases the synthesis of prothrombin (needs closely monitored. to prevent excess bleeding)
what does streptokinase do?
allows strep bacteria to degrade blood clots
what does urokinase do?
naturally made by the kidneys and degrades small blood clots
what does TPA stand for?
tissue plasminogen activator (short 1/2 life)
what does aspirin do?
decreases platelet adhesiveness which inhibits clot formation
what is disseminated intravascular coagulation (DIC)?
the pathological activation of the coagulation process leading to wide spread clot formation and active bleeding
how does active bleeding occur in DIC?
active bleeding is a result of clotting factors and platelets being all used up and the body being unable to replenish them adequatley
how is clotting is initiated by in DIC?
endothelial damage- bacterial toxins(DIC freq. occurs with septic shock)
major tissue damage-trauma and burns
obstetric complication-placenta rich in thromboplastin (rupture, retained placenta and fetus)
cancer-destroys surrounding tissues, release of thromboplastin,clotting
what does DIC cause?
clots form in microcirculation-impede blood flow-ischemia in capillaries-capillary rupture-active bleeding-organs can fail (kidney)
what is the treatment for DIC?
transfusion
platelet replacement
heparin
antithrombin 3(neutralizes thrombin)
what Is thrombocytopenia?
the decreased # of circulating thrombocytes
what are the causes of thrombocytopenia?
increases destruction of use
decreased production
increased sequestering in the spleen (splenomegaly or liver cirrhosis)
what are the consequences of thrombocytopenia?
bleeding in small vessels
if the spleen in removed or contracts-minute clots in the small vessels break leading to hemorrhage
what is impaired hemostasis in these coagulation and platelet disorders?
inability to promote coagulation and development of a stable fibrin clot
what is the cause of thrombocythemia
