Heparin-Induced Thrombocytopenia Following Tinzaparin Administration: A Case Report

Heparin-induced thrombocytopenia (HIT), a severe immune-mediated reaction, presents a significant diagnostic challenge, particularly with atypical symptoms like syncope or when induced by low-molecular-weight heparin (LMWH). This report describes the case of a 77-year-old male who developed severe thrombocytopenia following tinzaparin administration for bridging therapy after an elective endovascular aneurysm repair (EVAR). The patient presented to the emergency department with syncope, an uncommon manifestation of HIT. Initial investigations revealed isolated thrombocytopenia, and a high clinical suspicion based on a 4Ts score of 6 prompted the immediate discontinuation of tinzaparin and initiation of fondaparinux. The diagnosis was subsequently confirmed by a positive HIT antibody screening test. The patient's platelet counts improved in a few days, and he was successfully transitioned to warfarin without complications. This case highlights the critical importance of maintaining a high index of suspicion for HIT in any patient exposed to Heparin products, including LMWH, who develops thrombocytopenia, even when the clinical presentation is atypical. Early recognition and prompt management with alternative anticoagulants are essential to prevent life-threatening thromboembolic complications.