Kai Mbbs Yu

Rationale: Heparin-induced thrombocytopenia (HIT), a potentially devastating form of drug-induced thrombocytopenia, occurs in patients receiving heparin for thrombosis prevention or treatment. An isolated HIT is characterized by decreased platelet counts without thrombosis, which are atypical and difficult to clinically find. Symptoms and clinical findings: A 33-year-old female patient’s admission examination revealed elevated D-dimer levels. After prophylactic anticoagulation using low-molecular weight heparin, her blood platelet counts were rapidly decreased, whereas her D-dimer levels increased, followed by presentations of chest tightness, abdominal pain, and skin itching without thrombosis. After excluding all the other causes of thrombocytopenia, HIT was suspected. Her 4Ts score was 5 points, and enzyme-linked immunoassay for platelet factor 4 (PF4)/heparin antibodies was positive, indicating isolated HIT. Diagnoses, interventions, and outcomes: The patient was diagnosed with advanced lung cancer presenting with isolated HIT. We immediately stopped low-molecular weight heparin and initiated rivaroxaban for anticoagulation. We administered thrombopoietin (TPO) and avatripopal maleate tablets to increase blood platelet counts, whereas intravenous immunoglobulin (IVIG) was administered to stimulate her immune system. The patient’s thrombocytopenia was successfully treated without thrombosis and bleeding complications. Lessons: Rivaroxaban is a potential option for tumor preventive anticoagulation and HIT treatment. Early HIT identification is necessary. After identification, the 4Ts score as well as PF4/heparin antibodies should be assessed and appropriate anticoagulants selected based on patients’ conditions.