HIT Flashcards
Type I HIT occurs within first __ days of heparin exposure
I
platelet count normalizes with continued heparin (non-immune)
Type II HIT occurs __ to __ days after heparin exposure
4, 10
major concern for thrombotic complications
__ is more likely to cause HIT
a. UFH
b. LMWH
a. UFH
Heparin/PF4 antibodies are always present in HIT
a. true
b. false
a. true
can be present tin pts without HIT (not specific)
Heparin is sulfated
a. true
b. false
a. true
Pathophys of HIT:
Heparin binding to __ causes conformational change
PF4
antigenic sites on PF4 exposed
causes more and more PF4 production
interacts with endothelial lining of blood vessel
Pathophys of HIT:
Activation of tissue factor can lead to __ production, which leads to thrombosis
thrombin
The 4T score is performed after checking labs
a. true
b. false
b. false
done BEFORE checking any labs
Parts of the 4 Ts?
thrombocytopenia
timing
thrombosis
other causes of thrombocytopenia
A 4T score of __ to __ does not need further labs
0, 3
low probabilityu
What 4T score is intermediate probability?
4-5
What 4T score is high probability?
6-8
The HIT/PF4 antibody test is highly __
a. sensitive
b. specific
a. sensitive
high sensitivity, moderate specificity
What test is the gold standard for HIT diagnosis?
SRA
serotonin release assay
high sensitivity and specificity
A 4T score of _ or higher should immediately d/c heparin
4
