Hemostasis 0502

Question 1

hemophilia A

Answer 1

factor VIII deficiency

Question 2

hemophilia B

Answer 2

factor IX deficiency

Question 3

vit K deficiency

Answer 3

decreased synthesis of factors II, VII, IX, X, protein C, protein S

Question 4

antithrombin

Answer 4

inhibits thrombin (II) and factors VII, IX, IX, XI, XII (active forms).
activated by HEPARIN.

Question 5

what protects factor XIII?

Answer 5

vWF

Question 6

protein C

Answer 6

activated by thrombomodulin (from endo cells).

along with protein S, inactivates factor V and VIII.

Question 7

tissue plasminogen activator (tPA)

Answer 7

converts plasminogen to plasmin.

Question 8

plasmin

Answer 8

cleaves fibrin mesh (THROMBOLYTIC)

Question 9

what activates factor XII (intrinsic)?

Answer 9

subendothelial collagen, basement memb, activated plts

*also HMWK

Question 10

what activates factor VII (extrinsic)?

Answer 10

tissue thromboplastin

Question 11

what does plasmin do?

Answer 11

1. break down fibrin mesh into fibrin degradation products

2. cleave C3 into C3a in complement cascade

Question 12

what converts prekallikrein to kallikrein?

Answer 12

activated factor XII

Question 13

what does kallikrein do?

Answer 13

convert high molec weight kininogen (HMWK) to bradykinin

Question 14

actions of bradykinin

Answer 14

1. increase vasodilation
2. increase permeability
3. increase pain

Question 15

which cells release pro-aggregation factors?

Answer 15

plts - release TXA2 (decrease bld flow, increase agg)

Question 16

which cells release anti-aggregation factors?

Answer 16

endo cells - release PGI2 and NO (increase bld flow, decrease agg)

Question 17

what facilitates plt adhesion?

Answer 17

vWf binds injured endo first.

plt binds to vWf via GpIb receptor.

Question 18

what facilitates plt aggregation?

Answer 18

plts release ADP which induce expression of GpIIbIIIa receptor.
fibrinogen binds GpIIbIIIa and link plts.

Question 19

what drug inhibits TXA2 synthesis?

Answer 19

aspirin - inhibits COX, which converts arach acid to TXA2

Question 20

what drugs inhibit ADP-induced expression of GpIIbIIIa?

Answer 20

ticlodipine and clopidogrel

Question 21

what inhibits GpIIbIIIa directly?

Answer 21

abciximab

Question 22

what increases ESR?

Answer 22

infection
inflamm dz (temporal arteritis, polymyalgia rheumatica)
malignant neoplasm
GI dz (UC)
pregnancy

*acute phase reactants can cause RBC aggregation and thus, increased ESR

Question 23

what decreases ESR?

Answer 23

polycythemia
sickle cell anemia
CHF
microcytosis
hypofibrinogenemia

Question 24

what lab is changed in hemophilia A and/or B?

Answer 24

increased PTT

Question 25

what lab is changed in vit K deficiency?

Answer 25

increased PT and PTT

Question 26

what lab is changed in Bernard Soulier disease?

Answer 26

decreased PC increased BT *GpIb deficiency - plt adhesion

Question 27

what lab is changed in Glanzmann thrombasthenia?

Answer 27

normal PC increased BT no plt clumping on smear *GpIIbIIIa deficiency - plt aggregation

Question 28

what lab is changed in idiopathic thrombocytopenic purpura?

Answer 28

decreased PC increased BT increased megakaryocytes in BM *anti-GpIIbIIIa Abs decrease plt survivial

Question 29

what lab is changed in TTP?

Answer 29

decreased PC increased BT schistocytes, increased LDH

Question 30

cause of TTP

Answer 30

deficiency of ADAMTS13 vWf metalloproteinase - increase in vWf multimers that increase plt aggregation (micro thrombi)

Question 31

what are the sx of TTP?

Answer 31

1. neuro sx 2. renal sx 3. fever 4. thrombocytopenia 5. microangiopathic hemolytic anemia

Question 32

what lab is changed in vWf disease?

Answer 32

``` PTT increase (due to loss of F VIII protection) BT increase ```

Question 33

vWf manifestations

Answer 33

defective plt plug formation (adhesion). mild mucosal and skin bleeding. AD inheritance. most common inherited bleeding d/o - mixed plt and coag d/o.

Question 34

ristocetin test with vWf

Answer 34

normally ristocetin induces plt agg by causing vWf to bind GpIb. without vWf, plt agg is impaired and test is abn.

Question 35

tx of vWf

Answer 35

DDAVP (desmopressin) - releases vWf from endo cells

Question 36

DIC definition

Answer 36

= disseminated intravascular coagulation. widespread activation of clotting cascade. leads to deficiency in clotting factors and consequent bleeding state. mixed plt and coag d/o.

Question 37

what lab is changed in DIC?

Answer 37

``` PC decrease (used in microthrombi) BT increase PT increase PTT increase schistocytes D-dimers (fibrin split product) decrease fibrinogen decrease factors V,VIII ```

Question 38

causes of DIC

Answer 38

``` "STOP Making New Thrombi" Sepsis (gm neg) Trauma Obstetric complications acute Pancreatitis Malignancy Nephrotic syndrome Transfusion ```

Question 39

factor V Leiden

Answer 39

hereditary thrombosis syndrome leading to hypercoag - most common cause. production of mutant factor V that CANNOT be degraded by protein C.

Question 40

prothrombin gene mutation

Answer 40

hereditary thrombosis syndrome leading to hypercoag. mutation in 3' untranslated region. increased gene expression. increased prothrombin = increased thrombin. assoc. w/ venous clots.

Question 41

antithrombin deficiency

Answer 41

hereditary thrombosis syndrome leading to hypercoag. less increase in PTT after heparin admin. *ATIII is normally activated by heparin

Question 42

protein C or S deficiency

Answer 42

hereditary thrombosis syndrome leading to hypercoag. decreased ability to inactivate factors V, VIII.

Question 43

thrombotic skin necrosis with warfarin

Answer 43

normally, warfarin initiation leads to temporary deficit in prot C and S (shorter half life) relative to factors II, VII, IX, X. increased risk in prot C or S deficiency - more severe deficit is seen with warfarin initiation, leading to increased thrombosis in skin (about 1 wk later)

Question 44

bld transfusion: packed RBCs

Answer 44

increase Hb and O2 carrying capacity. | for acute bld loss, severe anemia.

Question 45

bld transfusion: plts

Answer 45

increase plt count. usu given in "6 pack" or more for therapeutic effect. stops significant bleeding (thrombocytopenia, qualitative plt defects).

Question 46

bld transfusion: fresh frozen plasma

Answer 46

increase coag factor levels by about 20%. | for DIC, cirrhosis, warfarin OVER-anticoagulation.

Question 47

bld transfusion: cryoprecipitate

Answer 47

contains fibrinogen, factor VIII, factor XIII, vWF. | to treat coag factor deficiencies involving fibrinogen and factor VIII.

Question 48

risks of bld transfusion

Answer 48

infection transmission -low. transfusion rxns. iron overload. hypocalcemia -citrate used as anticoagulant but may also chelate calcium (paresthesias). hyperkalemia -RBCs may lyse in old bld units.