Vancomycin-Mediated Drug-Induced Immune Thrombocytopenia

Background: Except for the frequently occurring heparininduced thrombocytopenia, drug-induced thrombocytopenias are a rare side effect of drug treatment. Since bleeding complications may be life-threatening, they require a fast and reliable diagnosis. A common problem, however, is to clearly identify the drug as the causative agent of the thrombocytopenic event. Case Report: The platelet count of a 72-year-old patient undergoing cardiac surgery and treated with vancomycin dropped to a nadir of 3,000/µl. Tests for the detection of drug-dependent antibodies using an indirect platelet immunofluorescence assay revealed vancomycin-dependent, platelet-reactive antibodies. Based on this case report, criteria and aspects of this drug-induced form of thrombocytopenia are discussed. Conclusions: In cases of drug-induced immune- mediated thrombocytopenia other than heparinmediated, the detection of drug-dependent, platelet-directed antibodies should be accepted as a diagnostic criterion. Vancomycin-mediated immune thrombocytopenia may occur more frequently than suggested by the number of published cases.