Hemorrhage

Question 1

vonwillebrands disease

Answer 1

defect in vW factor

1% prevelance

often unidentified

symptoms: epistaxis, bruising, menorrhagia, GI, gum bleeding

3 types: missing factor, not enough factor, enough but deficient

diagnosis: measure factor 8, vWAg
treated: ddAVP

Question 2

hemophilia A

Answer 2

factor 8 deficiency

x-linked, 1/10,000 males

Question 3

hemophilia B

Answer 3

factor 9 deficiency

x-linked

Question 4

hemophilia C

Answer 4

factor 11 deficiency

recessive, very rare

Question 5

DIC

Answer 5

platelet or clotting factor consumption, excess fibrinolysis

Question 6

inhibitors

Answer 6

Abs to clotting factors, usually to factor 8

Question 7

bernard soulier syndrome

Answer 7

defiency of GPIB (important for adhesion to subendothelial matrix)

autosomal recessive

S/S: early childhood brusing, mucosal bleeding

Dx: inc BT, giant platelets, thrombocytopenia

Rx: platelets, ddAVP

Question 8

glanzmanns thromboasthenia

Answer 8

autosomal recessive

GPIIa/IIIb defiency (cross linking platelets together)

early childhood bruising, bleeding

Dx: BT, Plt aggregation studies

Question 9

virchow triad

Answer 9

endothelial injury, abnormal blood flow, or hypercoagulability cause clotting

Question 10

how does stasis contribute to clots? where might you find stasis?

Answer 10

disruption of laminar flow;

prevents dilution of activator factors

retards clotting factor inhibiotrs

promotes endothelial cell activation

found: atherosclerotic plaques, aneurysms, MIs, valve stenosis

Question 11

hypercoaguability risk factors

Answer 11

primary:

APC resistance
protein C def
protein S def
fibrinolysis def
homocysteineima
prothrombin gene mutations

secondary
bed rest
MI
tissue damage
cancer
DIC
antiphospholipid Ab syndrome

Question 12

activated protein C resistance

Answer 12

factor 5 leiden mutation

usually protein C inactivates factor 5

in this mutation, factor 5 cannot be inactivated b/c of an AA substitution at the APC binding site

found in caucasions, 5-fold risk of thrombosis, and 30-fold if on oral contraceptives

Question 13

prothrombin 20210 mutation

Answer 13

increased prothrombin levels d/t increased mRNA stability

rel risk increased by 2-4%

Question 14

tests exist for factor 5 leiden and prothrombin 20210 because they are only single mutations

Answer 14

ok

Question 15

DIC

Answer 15

disseminated intravascular coagulation

inappropriate coagulation leads to thrombosis of microvessels

consumption of procoagulants and excess plasmin generation leads to hemorrhage

Question 16

DIC lab findings

Answer 16

thrombocytopenia
prolonged screening coag tests
elevated D dimer
fragmented RBCs

Question 17

HIT

Answer 17

heparin induced thrombocytopenia syndrome

generation of Abs to PF4, binds to platelets and creates a prothrombotic state

avoid w/ low molecular weight heparin

Question 18

antiphospholipid antibody syndrome

Answer 18

hughes syndrome

positive for antiphospholipid Ab for 6 weeks w/ on of

arterial venous thrombosis; thrombocytopenia; frequent miscarriages

creates Abs against phospholipids that can be d/t autoimmune disease or unknown cause

treatment: warfarin, heparin, steroids

Question 19

bleeding time

Answer 19

assess:

vascular component (endothelium)

and

platelets

caveats: poor predicative value for hemostatic problems
does not correlate w/ platelet dysfunction

not useful

Question 20

platelet count

Answer 20

PT- measures extrinsic pathway

PTT- measures intrinsic pathway

test= plasma + TF, Ca, phospholipid

normal- 10-14 sec

prolonged = deficiencies in 7, 10, 5 , 2, fibrinogen or inhibtiors

Question 21

use for PT

Answer 21

used to monitor warfarin time (interferes w/ K)

Question 22

INR

Answer 22

a way of standardizing warfarin treatment across labs

Question 23

PTT assay

Answer 23

plasma + contact activator, phospholipid, incubate 2-5 minutes, CaCl2 -> clot

23-33 seconds

deficiencies in 8, 9, 11, 12 or inhibitors

Question 24

mixing studies

Answer 24

to differentiate between having an increased PT/PTT b/c of deficiency or inhibitor

add normal plasma. if corrected, deficiency is the problem. if not, inhibtor is present