Ultra-Low Dose Argatroban in Heparin-Induced Thrombocytopenia with Thrombocytopenia and Hypofibrinogenemia: A Case Report

Heparin-induced thrombocytopenia (HIT) with thrombosis typically necessitates immediate therapeuticdose anticoagulation, yet management becomes exceedingly complex when a profound bleeding risk coexists. We report a unique case of serologically confirmed HIT developing during low-molecularweight heparin prophylaxis following major trauma in a 67-year-old man. On day 10 of heparin exposure, the patient presented with platelet count declining from 169×10⁹/L to 20×10⁹/L (91% reduction), hypofibrinogenemia (1.12 g/L), extensive deep vein thrombosis, and pulmonary embolism. Owing to extreme bleeding risk, argatroban initiation was deferred for 48 hours post-diagnosis, then cautiously titrated from 0.08 to 0.67 μg/kg/min guided by dynamic coagulation-fibrinolysis markers (thrombinantithrombin complex, plasmin-α2-antiplasmin complex, and D-dimer). These markers provided realtime assessment of treatment response, declining substantially prior to platelet count normalization. By day 12 post-diagnosis, platelet count recovered to 176×10⁹/L, permitting successful definitive orthopedic surgery on day 13 without bleeding complications. This case illustrates that in HIT with lifethreatening thrombosis and extreme bleeding risk, an individualized "start low, go slow" argatroban strategy with delayed initiation achieves effective anticoagulation while minimizing hemorrhagic risk.