High Yield: Ch 4: Hemostasis and Related Disorders

Question 1

vWF

Answer 1

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

Question 2

Autoimmune production of IgG against platelet antigens (GPIIb/IIIa). Decreased platelet count, nml PT/PTT; Increased megakaryocytes on bonemarrow biopsy.

Answer 2

Immune Thrombocytopenic Purpura [ITP]

Question 3

Tx of ITP

Answer 3

Initial: cortico steroids. IVIG raises platelet count in sx bleeding (short lived). Refractory cases = splenectomy

Question 4

Lab: Thrombocytopenia, inc bleeding time; nml PT/PTT; Anemia with Schistocytes; inc megakaryocytes.

Answer 4

Microangiopathic hemolytic anemia. Either Thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS)

Question 5

HUS vs TTP both are a microangiopathic hemolytic anemia

Answer 5

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.

Question 6

Genetic GP1b deficiency. blood smear shows mild thrombocytopenia with enlarged platelets. Impaired platelet adhesion.

Answer 6

Bernard-Soulier syndrome

Question 7

Genetic GPIIb/IIIa deficiency. platelet aggregation is impaired.

Answer 7

Glanzmann thrombasthenia

Question 8

x-linked recessive Factor VIII deficiency. Increase PTT; nml PT, platelet and bleeding time.

Answer 8

Hemophilia A [ recombinant FVIII = tx]

Question 9

Genetic factor IX deficiency. increased PTT

Answer 9

Hemophilia B [X-mas disease]

Question 10

Inc bleeding time and PTT. nml PT. Abnormal ristocetin test.

Answer 10

Von Villebrand disease. Tx = desmopressin[ADH analog - increases vWF release from Weibel-Palade bodies]

Question 11

Drug that blocks epoxide reductase

Answer 11

Coumadin. Epoxide reductase activates vitamin K in the liver.

Question 12

Dec platelet count; dec fibrinogen; inc PT/PTT; schictocytes; elevated fibrin split products (D-Dimer)

Answer 12

DIC Tx: transfusing blood products and cryoprecipitate

Question 13

Virchow triad

Answer 13

3 major risk factors for thrombosis. 1. disruption of blood flow. 2. endothelial cell damage; 3. hypercoaguable state

Question 14

Lines of Zahn

Answer 14

seen in thrombosis. alternating layers of platelets/fibrin and RBCs

Question 15

PGI2

Answer 15

Vasodilation and inhibition of platelet aggregation. produced by endothelial cells

Question 16

Protein C

Answer 16

Inactivates factors 5 and 8. activated by thrombin when thrombin is acted on by thrombomodulin.

Question 17

Vessel thrombosis, mental retardation, lens dislocation, long slender fingers. homocysteine levels increased with homocystinuria

Answer 17

Cystathionine beta synthase (CBS) deficiency. CBS converts homocystein to cystathionine

Question 18

order of warfarin/Coumadin/heparin

Answer 18

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.

Question 19

mutated factor ___ which lacks cleavage side for deactivation by protein C and S

Answer 19

Factor V Leiden