PHRM 111 Lecture Notes - Lecture 7: Thrombotic Thrombocytopenic Purpura, Chronic Liver Disease, Eptifibatide
Document Summary
Heparin-induced thrombocytopenia (hit): low platelet count caused by heparin. Type ii occurs in ~5% of patients receiving ufh for 4 days and <1% of patients receiving lmwh. Due to clumping of platelets (but still functional ) Early onset (within 1-4 days of heparin exposure) ~1 in 5000 hospitalized patients (thrombotic complications occur in ~50% patients) More likely to cause venous (e. g. dvt, pe) vs arterial (e. g. More likely to cause venous (e. g. dvt, pe) vs arterial (e. g. limb) thrombosis. Delayed response ( 5-10 days after heparin exposure) Platelet count decrease by 50% (depending on patient"s baseline) Can occur abruptly in patients with recent (within last 3 months) heparin exposure (especially 30 days) Discontinue all heparin products and initiate non-heparin anticoagulant immediately. Platelet factor 4 (pf4) binds to heparin to form a complex recognized as foreign. Antibodies activate platelets and trigger a prothrombotic state excessive thrombin generation. Note: low platelet count due to sequestration (all clumped together activated).
