AB162. SOH24AB_095. Heparin-induced thrombocytopenia complicating orthopaedic surgery: a challenging case in an elderly patient

Background: Heparin-induced thrombocytopenia (HIT) is an uncommon yet critical immune-mediated complication associated with heparin exposure. Defined by the formation of antibodies against the heparin-platelet factor 4 (PF4) complex, HIT presents with thrombocytopenia and paradoxically, a prothrombotic state.

Case Description: In this case study, we present the clinical course of a 78-year-old male admitted with a femoral neck fracture who underwent surgical intervention with intramedullary (IM) nailing. Prior to admission, a 78-year-old male was anticoagulated with edoxaban for known atrial fibrillation. Despite being switched back to edoxaban for venous thromboembolism prophylaxis, on day 4 post operation, a hematoma necessitated the reintroduction of enoxaparin for its easy reversibility. Meanwhile postoperative anaemia led to a red cell concentrate transfusion. During this short period of a few days, his platelet concentration dropped from 198×10⁹ to 20×10⁹/L. Exhaustive exclusion of alternative causes and an elevated 4T score prompted laboratory investigations, confirming the presence of anti-PF4 antibodies, consistent with HIT. Immediate cessation of heparin therapy ensued, and alternative anticoagulation with fondaparinux was initiated, resulting in gradual platelet count improvement and hematoma stabilization.

Conclusions: This case underscores the intricate challenges in managing HIT within the orthopaedic surgical context. Diagnosis complexities arise from the potential masking effect of coexisting factors, including surgery-related thrombocytopenia, complex patient variables such as anticoagulation, and the administration of blood products. Timely recognition of HIT is imperative, given its potential for severe morbidity and mortality. Healthcare providers are urged to maintain vigilance, contemplate alternative anticoagulation strategies, and collaborate closely with haematology specialists when navigating such intricate cases, ultimately ensuring optimal patient outcomes. The rarity of HIT does not diminish its clinical significance, as its potential for severe thrombotic complications highlights the importance of astute clinical management in preventing limb or organ-threatening events.

Keywords: Thrombocytopenia; platelet; heparin; thromboembolism; anticoagulation