Vancomycin-Induced Immune Thrombocytopenia in an Older Patient in the Intensive Care Unit: A Case Report: Letter to the Editor

To the Editor, Thrombocytopenia is a frequent finding in patients treated in intensive care units, and determining its exact cause is essential for proper management. Among many possible etiologies, drug-related immune thrombocytopenia (DITP) is uncommon but clinically relevant. The disorder occurs when drug-dependent antibodies react with platelet surface glycoproteins, mainly GPIb/IX/V or GPIIb/IIIa, leading to immune-mediated destruction of platelets. Early recognition and discontinuation of the suspected medication are crucial to avoid potentially severe bleeding events (1-4). Vancomycin is a glycopeptide antibiotic that inhibits bacterial cell wall synthesis and is used to treat gram-positive infections, particularly methicillin-resistant Staphylococcus aureus (5). In rare cases, vancomycin may trigger immune-mediated thrombocytopenia through a quinine-like mechanism. The drug can promote the formation of drug-dependent antibodies that bind to platelet glycoproteins such as GPIIb/IIIa, leading to immune destruction and platelet clearance (2, 6). In this letter, we describe a patient with septic shock who developed vancomycin-associated immune thrombocytopenia during intensive care treatment. A 65-year-old woman with a history of ischemic cerebrovascular disease was admitted to the intensive care unit (ICU) due to fever and deterioration in her general condition. She was immobilized and had chronic comorbidities including diabetes mellitus, hypertension, and recent ischemic stroke. On admission, she fulfilled the criteria for septic shock secondary to a urinary tract infection, with an increase of more than two points in the Sequential Organ Failure Assessment (SOFA) score, hypotension requiring vasopressor support, and lactate levels exceeding 2 mmol/L. She was started on intravenous hydration, empiric broad-spectrum antibiotics (meropenem and vancomycin), vasopressors, and corticosteroids. Initial laboratory tests revealed leukocytosis, elevated inflammatory markers (CRP and procalcitonin), increased urea ...