Master the board step 3

Master the Boards: USMLE Step 3
Thrombophilia/Hypercoagulable States
Cause
Lupus Antiphospholipid
Syndromes,
Anticoagulant, or
Anticardiolipin
Antibodies
Protein C
Deficiency
Factor V Leiden
Mutation
Antithrombin
Deficiency
Presentation
Venous or arterial
thrombosis
Elevated aPTT with a
normal PT
Spontaneous abortion
False positive VDRL
Skin necrosis
with the use of
warfarin
Venous thrombosis
Most common cause
of thrombophilia
Venous thrombosis
No change in the
aPTT with a bolus
of IV heparin
Venous thrombosis
Diagnostic Test
Mixing study first
Russel viper venom test
is most accurate for
lupus anticoagulant
Protein C level
Factor V mutation
test
Level of
antithrombin III
Treatment
Heparin followed by
warfarin
Heparin followed by
warfarin
Heparin followed by
warfarin
Large amounts of
heparin or direct
thrombin inhibitor
followed by
warfarin
Basic Science Correlate
Mechanism of Factor V Mutation
Protein C inactivates factor V—but only in its normal form. If factor V has
a mutation, protein C will not inhibit it. Factor V mutation functions like
protein C deficiency.
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