an abrupt reduction in platelet
counts with a history of recent surgery suggests
an immunologic cause or adverse transfusion reaction
(post-transfusion purpura or drug-induced
thrombocytopenia).
Heparin-induced thrombocytopenic
thrombosis is an uncommon, transient,
drug-induced, autoimmune prothrombotic disorder
caused by the formation of IgG antibodies
that cause platelet activation by the formation of
antibodies to complexes of platelet factor 4 and
heparin.32