Qinan Yin, Lizhu Han, Yuan Bian, Yujie Song, Youjin Huang
Objective To describe the clinical management of heparin-induced thrombocytopenia with thrombosis (HITT) after orthopedic surgery and to highlight the role of clinical pharmacists in early recognition and individualized anticoagulant therapy. Methods An 85-year-old woman developed HITT after right hip hemiarthroplasty and low molecular weight heparin thromboprophylaxis. Following the development of thrombocytopenia and new thrombotic events, clinical pharmacists participated in multidisciplinary evaluations, calculated the 4Ts score, recommended HIT antibody testing, and assisted in anticoagulant adjustment. Platelet count, D-dimer levels, renal function, and anti-PF4/heparin antibody levels were monitored throughout hospitalization. Results The patient developed bilateral calf intermuscular venous thrombosis and multiple pulmonary emboli following orthopedic surgery. The 4Ts score was 6, and anti-PF4/heparin antibody testing was positive (5.7 U/mL; reference range, 0–1.0 U/mL), confirming the diagnosis of HITT. Enoxaparin was discontinued, and anticoagulation was switched to fondaparinux sodium. Platelet counts gradually recovered from 27 × 10 9 /L to 253 × 10 9 /L during follow-up, with no recurrent thrombosis or bleeding events reported during the available follow-up period. Conclusion HITT after orthopedic surgery may be difficult to recognize because postoperative thrombocytopenia has multiple causes. This case highlights the importance of timely assessment of HIT probability and multidisciplinary collaboration. Clinical pharmacists may contribute to the early diagnosis, appropriate anticoagulant modification, and individualized management of patients with complex anticoagulation needs.