Severe immune thrombocytopenia induced by vancomycin in a critically ill patient: a case report and literature review.

BACKGROUND: Vancomycin-induced immune thrombocytopenia (VIIT) is a rare but potentially life-threatening adverse drug reaction characterized by profound platelet destruction. Diagnosis is challenging in critically ill patients, and optimal management beyond drug cessation remains poorly defined. A 54-year-old female admitted to the ICU for severe community-acquired pneumonia developed profound, refractory thrombocytopenia 12 days after the initiation of vancomycin. Blood, sputum, and pleural fluid cultures were negative. Vancomycin was continued due to the severity of the pneumonia, a fluctuating clinical course with recurrent fevers and progressive infiltrates, a complicated parapneumonic effusion requiring drainage and surgical consultation, and infectious disease service recommendations. The patient presented with gross hematuria and a rapid decline in platelet count to 6,000/µL. Following the exclusion of alternative etiologies-including sepsis-associated coagulopathy and heparin-induced thrombocytopenia (HIT)-vancomycin was discontinued. The patient required intravenous immunoglobulin (IVIG) and corticosteroids in addition to drug cessation to achieve platelet recovery. CONCLUSION: This case underscores the critical importance of early recognition of VIIT. Our literature review reveals that while discontinuation of the offending agent is the cornerstone of therapy, severe cases (platelets < 20,000/µL) often require adjunctive immunomodulatory treatment. VIIT should remain a primary differential diagnosis in patients presenting with unexplained thrombocytopenia during vancomycin therapy.