thrombophilia Flashcards
what are the two types of thrombophilia ?
inherited and acquired
what are the different causes of inherited thrombophilia?
1- deficiency of natural anticoagulants
2- prothrombin mutation
3- defect in fibrinolytic system
4- hyper-homocysteinemia
what are the types of acquired thrombophilia ?
lupus anticoagulant
myeloproliferative disease : polycythemia
heparin induced thrombocytopenia and thrombosis
what are the different deficiencies of natural coagulants ?
anti thrombin 3 deficiency
heparin cofactor 2 deficiency
protein C or S deficiency
factor V leiden
what happens with factors V leiden ?
resistance to activated protein C
when do we suspect anti-thrombin deficiency ?
1- in young patients
2- pregnancy related VT
3- therapeutic heparin in excess with no prolongation in PTT
suggestive of heparin resistance
what are the acquired conditions associated with anti thrombin deficiency ?
nephrotic syndrome
DIC
severe liver disease
what is the genetic inheritance associated with antithrombin deficiency ?
autosomal dominant
what is the function of protein C ?
cleavage of factor 8 and factor 5
what is the end result of protein C deficiency ?
associated with hypercoaguable state
what are the vitamin K dependent factors ?
protein s
protein C
factor 2,7,9,10
what testing is used for protein C ?
functional assay oor antigenic assay
ELISA
immunoelectrophoresis
what is the most common inherited thrombophilia ?
factor V leiden
activated protein c resistance
what is factor V deactivated by ?
protein C , if it cannot be cleaved it makes it more likely for the formation of VTE
what happens in prothrombin mutations ?
increase in prothrombin levels , increases thrombotic risk
what does a mutation in MTHFR cause ?
homocystenuria
what is the diagnostic criteria for APL ?
lab criteria :
anticardiolipin
anti b2 Glycoprotein
lupus anticoagulant
all positive , on 2 separate occasions 12 weeks apart
clinical criteria :
vascular thrombosis
pregnancy complications
what happens in heparin indued thrombocytopenia ?
before heparin therapy perform platelet count
if the platelete count decreases , this is HIT
elevation of RBC and thrombophilia ?
polycythemia vera
prolonged PTT not corrected by the addition of normal plasma ( mixing study) suggests ?
lupus anticoagulant or acquired inhibitors
who should be tested for inherited thrombophilia ?
increased risk of recurrence in early ages
patients with a positive family history
what are the tests for inherited thrombophilia ?
factor V leiden
Protein C and protein S deficiency
antithrombin 3 deficiency
prothrombin mutation
MTHFR mutation
what is the best time for performing thrombophilia testing ?
1- usually best delayed until at least 1 month after completion of a course of anticoag therapy
2- should be avoided in pregnancy or if thee patient is on the pill
what type of heparin is associated with HITT ?
unfractionated or heavy weight heparin
what does persistant high level 1 month after stoppage of warfarin suggest ?
may predict recurrence
what tests can be used to detect defective fibrinolytic system ?
plasminogen
PA
PAI
what tests can be performed to detect increased platelet activity ?
increased PF4
PFA-100 decreased closure time
what is the thrombophilia panel by PCR ?
Factor V G1691A (Leiden)
Factor II Prothrombin G20210A
MTHFR C677T/A1298C
relationship between protein c and protein s?
PS increases the affinity off PC to bind to thee phospholipid on the surface of platelets
what is the inactive form of protein S ?
C4b bound PS
if everything is high except fibrinogen and platelets what is the most likely diagnosis ?
DIC
