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

Heparin-induced thrombocytopenia (HIT) with thrombosis typically necessitates immediate therapeutic-dose anticoagulation, yet management becomes exceedingly complex when a profound bleeding risk coexists. We report a unique case of serologically confirmed HIT developing during low-molecular-weight heparin prophylaxis following major trauma in a 67-year-old man. On day 10 of heparin exposure, the patient presented with a platelet count declining from 169 × 10 9 /L to 20 × 10 9 /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 postdiagnosis, then cautiously titrated from 0.08 to 0.67 μg/kg/min guided by dynamic coagulation-fibrinolysis markers (thrombin-antithrombin complex, plasmin-α2-antiplasmin complex, and D-dimer). These markers provided real-time assessment of treatment response, declining substantially prior to platelet count normalization. By day 12 postdiagnosis, platelet count recovered to 176 × 10 9 /L, permitting successful definitive orthopedic surgery on day 13 without bleeding complications. This case illustrates that in HIT with life-threatening thrombosis and extreme bleeding risk, an individualized "start low, go slow" argatroban strategy with delayed initiation achieves effective anticoagulation while minimizing hemorrhagic risk.