Vancomycin-induced thrombocytopenia in endocarditis: A case report and review of literature

Abstract

Background: Thrombocytopenia is a serious complication in the medical practice of numerous drugs. Vancomycin is frequently used for the prophylaxis and treatment of suspected or identified methicillin-resistant positive infections. Several cases with vancomycin-induced thrombocytopenia (VIT) have been reported. However, these have rarely been extensively reviewed. The present report describes a case of VIT in endocarditis, and reviews all VIT cases reported in the literature.

Case summary: A 26-year-old male diagnosed with infective endocarditis was admitted. The patient was treated with multiple drugs, including vancomycin, which was initially intravenously given at 1000 mg every 12 h and subsequently at 500 mg every 8 h on day 3. On day 11, the platelet count decreased to 51 × 10⁹/L, vancomycin was switched to 500 mg every 12 h, and platelet transfusion was given. On day 17, the platelet count dropped to 27 × 10⁹/L, and platelet transfusion was administered again. On day 23, vancomycin was adjusted to 500 mg every 8 h as the trough concentration dropped to the minimum effective concentration. On day 33, the platelet count declined to approximately 40 × 10⁹/L. After platelet transfusion, the platelet count rebounded to 90 × 10⁹/L on day 35 but dropped again to 42 × 10⁹/L on day 43. Based on the time-to-platelet count curve and Naranjo's Adverse Drug Reaction Probability Scale score, VIT was suspected. After vancomycin discontinuation and platelet transfusion, the platelet count gradually normalized.

Conclusion: The diagnosis of VIT can be achieved through the time-to-platelet count curve and Naranjo's Adverse Drug Reaction Probability Scale score. The platelet count cannot be normalized simply by platelet transfusion alone, and vancomycin discontinuation is essential.

Keywords: Case report; Endocarditis; Literature review; Platelet transfusion; Thrombocytopenia; Vancomycin.

Figure 1

Time-to-platelet count curve during hospitalization. Vancomycin was initiated on day 2 and continued on day 43, as indicated by the downward arrows. Platelet transfusion was given on day 11, 17, 33, and 43, as indicated by the upward arrows.