title: Very severe thrombocytopenia and fragmentation hemolysis mimicking thrombotic thrombocytopenic purpura associated with a giant intracardiac vegetation infected with Staphylococcus epidermidis: role of monocyte procoagulant activity induced by bacterial supernatant.
abstract: The pathogenesis of very severe thrombocytopenia in bacterial endocarditis is uncertain. We report a 50-year-old male with platelet counts < 10 x 10(9)/l and fragmentation hemolysis complicating Staphylococcus epidermidis pacemaker endocarditis with a giant vegetation. Antibiotics, corticosteroids, high-dose intravenous gammaglobulin, and plasmapheresis (for initially-suspected thrombotic thrombocytopenic purpura) failed to produce significant platelet count increase. However, therapeutic-dose heparin anticoagulation was associated with a platelet count increase from <10 to approximately 40 x 10(9)/l, with parallel reduction in thrombin-antithrombin complexes (from 8.9 to 3.5 microg/l), facilitating surgical intervention. The thrombocytopenia promptly resolved following surgical removal of the vegetation. Culture supernatant from S. epidermidis isolated from the patient's blood induced monocytes to express procoagulant activity (assessed by factor Xa generation) equivalent to lipopolysaccharide (1 microg/ml), with half-maximal activation seen with culture supernatant diluted to 1:12,800. These data are consistent with previous animal models of endocarditis demonstrating staphylococci-induced procoagulant changes in monocytes. This case demonstrates that heparin anticoagulation can be therapeutic in infective endocarditis-associated severe thrombocytopenia in a non-bleeding patient, and that such therapy may ameliorate the platelet count enough to permit surgical intervention.
authors.affiliation: Department of Transfusion Medicine and Immunology, Ernst-Moritz-Arndt University Greifswald, Greifswald, Germany.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Selleng
authors.forename: Theodore E
authors.initials: TE
authors.lastname: Warkentin
authors.forename: Andreas
authors.initials: A
authors.lastname: Greinacher
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Morris
authors.forename: Irwin R
authors.initials: IR
authors.lastname: Walker
authors.forename: H Alexander
authors.initials: HA
authors.lastname: Heggtveit
authors.forename: Petra
authors.initials: P
authors.lastname: Eichler
authors.forename: Irene J
authors.initials: IJ
authors.lastname: Cybulsky
mesh_terms: D001777:Blood Coagulation; D002478:Cells, Cultured; D015951:Factor Xa / Q000096:biosynthesis; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008214:Lymphocytes / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011697:Purpura, Thrombotic Thrombocytopenic / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D013203:Staphylococcal Infections / Q000150:complications / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000502:physiology*; D013921:Thrombocytopenia / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism / Q000473:pathology*
chemical_list: D015951:Factor Xa