hemostasis Flashcards
what kind of bleeding do you see with primary d/o?
immediate small bleeds
its a platelet issue
list the primary hemostasis d/o (3)
platelet d/o
von willebrand dz
drug induced platelet dyfx
ITP
which meds can cause drug induced platelet dysfxn?
aspirin
NSAIDs
advil
what kind of bleeding do you see with secondary hemostasis d/o?
delayed, severe bleeding
platelets there; deficiencies or inhibitors in cascade
list the 4 secondary hemostasis d/o
hemophilias
acquired factor inhibitors
liver dz
DIC
what does DIC stand for
disseminated intravascular coagulation
what does ITP stand for
immune thrombocytopenic purpura
what is ITP?
a primary hemostasis d/o when antibodies attack platelets causing thrombocytopenia
what two glycoproteins are being attacked in ITP?
GP1B
GPIIB
what is drug induced platelet dysfunction?
a primary hemostasis d/o causing platelets to be either less functional or decreased in #
what is von willebrand’s disease
a primary hemostasis d/o of abnormal vWF (quantity or quality)
leads to mucocutaneous bleeding depending on type
what is hemophilia A and B?
a secondary hemostasis d/o
inherited decrease in factors 8 or 9
what is DIC?
a secondary hemostasis d/o
abnormal activation of clotting system in systemic illness; consumptive coagulopathy
labs that can screen for DIC
PT, PTT
platelet count
fibrinogen
D-dimers
FDP
expected PT and PTT and platelet count levels in DIC
high PT, PTT
expected platelet count and fibrinogen levels in DIC
both will be low
will D-dimers and FDP be present with DIC?
yes they both will
what are D-dimers and FDP?
D-dimers: product of blood clot
FDP: fibrinogen degradation products
5 scenarios to suspect a thrombophilia
unprovoked thrombosis at early age
familial tendency
thrombosis at odd site (artery, portal vein)
recurrent thrombosis
arterial vs venous thrombosis
what does Protein C & S depend on?
vitamin K
they are also reduced with warfarin
AT-III is lowered by what drug?
heparin
_____, _____, and ______ may be reduced w/ acute clotting
protein C
free protein S
AT-III
when should you test for hypercoaguable state?
before anticoagulants
2-3 wks after stopping anticoagulants
what is prothrombin time (PT/INR)
time it takes for factor VII to form complex with tissue factor and form a clot
monitors extrinsic pathway
what test do we use to monitor warfarin therapy?
prothrombin time
how does warfarin work in the body?
anticoagulant
vitamin K inhibitor to block factor 2,7,9,10
what do you give to reverse the effect of warfarin?
vitamin K
how do abx affect INR?
they increase it by decreasing the Vit K producing bacteria in the gut
what is normal INR goal when starting warfarin?
2-3
if they have artificial valve or if for secondary MI prevention then 2.5-3
why do you need to give a bridge when starting warfarin? what do you give as the bridge
pt is HYPERcoagulable for 5 days at start bc of long half life of prothrombin
protein C and S are blocked first and they normally do negative feedback
give heparin/LMWH bridge
what test can see the severity of liver dz?
prothrombin time
what test can screen for vitamin K deficiency?
prothrombin time
what is INR?
a way of standardizing PT values from diff labs
you divide PT by control and raise it to ISI
what is normal INR levels
0.9 to 1.2
what is normal PT time?
11 to 14 seconds
what should you give to a patient with INR > 9 w/o bleeding? how often should you recheck INR?
Vit K 2.5-5mg oral (no backup options)
recheck INR q 24hrs
when should you NOT give PCC or FFP?
never give it to non-bleeding patients
what to do in patient with INR 5-9 without bleeding (2 things)
maybe give 1-2.5mg vit K (don’t have to give if no major risk factors)
hold 1-2 doses of warfarin
recheck INR q 2-3 days
what to do in patient w/ INR <5 without bleeding
check INR q 2-3 days
hold 1 dose of warfarin
what is partial thromboplastin time (aPTT)
measures rate of the contact pathway (intrinsic pathway)
adding activator like clay to plasma
5 things that can cause elevated PTT
factor deficiency (12,11,10,9,5,2)
antiphospholipid antibodies
acquired factor inibitors
heparin
lupus (if its high in unreasonable setting)
what lab is used to monitor heparin?
aPTT
heparin anti-xa therapeutic (0.3 to 0.8)
when are mixing studies done?
to see if they are deficient or if the factors are just being inhibited
if you give mixing studies and it corrects, what does this mean?
it means they had a deficiency
if it did not correct then it’d mean the factors are being inhibited
what is the normal range for aPTT
25-40 seconds
how does heparin work? what’s the therapeutic range?
activates antithrombin III which inactivates IIA, VIIa-TF, IXa, Xa, XIa
therapeutic range is 40-70 secs
what is the major risk with heparin therapy?
bleeding- it can be internal if dose is too high
how do you reverse heparin? (what do you give?)
protamine sulfate!!!!
unfractionated vs LMWH heparin
unfractionated is IV and monitored
LMWH is SQ, longer, wt based and no need to monitor
what is heparin induced thrombocytopenia (HIT)
low platelet and thrombosis d/t antibodies to heparin/PF4 complex
what should you suspect when theres a decrease in platelets by >50% or levels <100k?
HIT
what should you do if someone has HIT? (4 things)
stop immediately and permanently
check antiPF5 antibody
confirm it
avoid platelet transfusion
2 ways to confirm HIT?
serotonin release assay or P-selectin expression assay (PEA)
what should you right after stopping heparin in patient with HIT? why?
a different anticoagulant like argatroban, fondaparinux, bivalirudin
bc heparin is still floating around in the body
what disorder is HIT similar to? how are they a bit different?
DIC except its more clotting than bleeding and the clots are huge
how does tPA work?
breaks down clot by cleaving plasminogen into plasmin and speeding up fibrinolysis
name the antiplatelet drug that blocks platelet ACTIVATION
Clopidogrel
name the antiplatelet drug that blocks platelet AGGREGATION
Aspirin
most common type of von Willebrand dz?
type 1– low vWF and mild sx
what type of von Willebrand dz is a qualitative issue?
type 2
what type of von Willebrand dz can resemble hemophilia?
type 3
4 initial testings for von Willebrand dz
vWF:Ag— its low
Ristocetin cofactor activity (vWF R:Co)– for activity measure
factor VIII activity
vWF multimers
what is thrombin time (TT)
measures conversion of fibrinogen to fibrin
3 things that elevate TT
hypo or dysfibrinogenemia
heparin
DIC
what is normal fibrinogen range?
175-400
2 things that cause decreased & increased Fibrinogen
decreased—DIC, liver dz
increased– inflammatory states, pregnancy
when do you do FDP/D-dimer testing?
to screen for clotting including DIC
when can you see FDP/D-dimer (6)
DIC
malignancy
liver dz
surgery
trauma
pregnancy
