Hemorrhage Flashcards
vonwillebrands disease
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
hemophilia A
factor 8 deficiency
x-linked, 1/10,000 males
hemophilia B
factor 9 deficiency
x-linked
hemophilia C
factor 11 deficiency
recessive, very rare
DIC
platelet or clotting factor consumption, excess fibrinolysis
inhibitors
Abs to clotting factors, usually to factor 8
bernard soulier syndrome
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
glanzmanns thromboasthenia
autosomal recessive
GPIIa/IIIb defiency (cross linking platelets together)
early childhood bruising, bleeding
Dx: BT, Plt aggregation studies
virchow triad
endothelial injury, abnormal blood flow, or hypercoagulability cause clotting
how does stasis contribute to clots? where might you find stasis?
disruption of laminar flow;
prevents dilution of activator factors
retards clotting factor inhibiotrs
promotes endothelial cell activation
found: atherosclerotic plaques, aneurysms, MIs, valve stenosis
hypercoaguability risk factors
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
activated protein C resistance
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
prothrombin 20210 mutation
increased prothrombin levels d/t increased mRNA stability
rel risk increased by 2-4%
tests exist for factor 5 leiden and prothrombin 20210 because they are only single mutations
ok
DIC
disseminated intravascular coagulation
inappropriate coagulation leads to thrombosis of microvessels
consumption of procoagulants and excess plasmin generation leads to hemorrhage
DIC lab findings
thrombocytopenia
prolonged screening coag tests
elevated D dimer
fragmented RBCs
HIT
heparin induced thrombocytopenia syndrome
generation of Abs to PF4, binds to platelets and creates a prothrombotic state
avoid w/ low molecular weight heparin
antiphospholipid antibody syndrome
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
bleeding time
assess:
vascular component (endothelium)
and
platelets
caveats: poor predicative value for hemostatic problems
does not correlate w/ platelet dysfunction
not useful
platelet count
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
use for PT
used to monitor warfarin time (interferes w/ K)
INR
a way of standardizing warfarin treatment across labs
PTT assay
plasma + contact activator, phospholipid, incubate 2-5 minutes, CaCl2 -> clot
23-33 seconds
deficiencies in 8, 9, 11, 12 or inhibitors
mixing studies
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
