High Yield: Ch 4: Hemostasis and Related Disorders Flashcards
vWF
binds exposed subendothelial collagen in primary hemostasis. Platelets bind to vWF using the GP1b receptor. vWF is derived from the Weibel-palade bodies of endothelial cells and alpha-granules of platelets
Autoimmune production of IgG against platelet antigens (GPIIb/IIIa). Decreased platelet count, nml PT/PTT; Increased megakaryocytes on bonemarrow biopsy.
Immune Thrombocytopenic Purpura [ITP]
Tx of ITP
Initial: cortico steroids. IVIG raises platelet count in sx bleeding (short lived). Refractory cases = splenectomy
Lab: Thrombocytopenia, inc bleeding time; nml PT/PTT; Anemia with Schistocytes; inc megakaryocytes.
Microangiopathic hemolytic anemia. Either Thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS)
HUS vs TTP both are a microangiopathic hemolytic anemia
TTP: due to decreased ADAMTS13 (nml cleaves vWF). CNS abnormalities.
HUS: due to endothelial damage by drugs or infection. E. coli (beef) - verotoxin. Renal insufficiency.
Genetic GP1b deficiency. blood smear shows mild thrombocytopenia with enlarged platelets. Impaired platelet adhesion.
Bernard-Soulier syndrome
Genetic GPIIb/IIIa deficiency. platelet aggregation is impaired.
Glanzmann thrombasthenia
x-linked recessive Factor VIII deficiency. Increase PTT; nml PT, platelet and bleeding time.
Hemophilia A [ recombinant FVIII = tx]
Genetic factor IX deficiency. increased PTT
Hemophilia B [X-mas disease]
Inc bleeding time and PTT. nml PT. Abnormal ristocetin test.
Von Villebrand disease. Tx = desmopressin[ADH analog - increases vWF release from Weibel-Palade bodies]
Drug that blocks epoxide reductase
Coumadin. Epoxide reductase activates vitamin K in the liver.
Dec platelet count; dec fibrinogen; inc PT/PTT; schictocytes; elevated fibrin split products (D-Dimer)
DIC Tx: transfusing blood products and cryoprecipitate
Virchow triad
3 major risk factors for thrombosis. 1. disruption of blood flow. 2. endothelial cell damage; 3. hypercoaguable state
Lines of Zahn
seen in thrombosis. alternating layers of platelets/fibrin and RBCs
PGI2
Vasodilation and inhibition of platelet aggregation. produced by endothelial cells
Protein C
Inactivates factors 5 and 8. activated by thrombin when thrombin is acted on by thrombomodulin.
Vessel thrombosis, mental retardation, lens dislocation, long slender fingers. homocysteine levels increased with homocystinuria
Cystathionine beta synthase (CBS) deficiency. CBS converts homocystein to cystathionine
order of warfarin/Coumadin/heparin
heparin first - then warfarin (which is Coumadin). done so because of protein C and S will be depeleted if warfarin first - risk warfarin skin necrosis.
mutated factor ___ which lacks cleavage side for deactivation by protein C and S
Factor V Leiden
