Acquired hemophilia a caused by complicated urinary tract infection due to flavobacterium odoratum

Rationale: Acquired hemophilia A (AHA) is a rare bleeding disorder characterized by the development of autoantibodies directed against coagulation factor VIII (FVIII). Approximately 50% of cases are idiopathic, while the remaining are associated with autoimmune conditions, malignancies, or infections. To date, there have been no reported cases of AHA secondary to Flavobacterium odoratum ( Frullania odoratum ) infection. Patient concerns: A male patient underwent ureteroscopic lithotripsy with double-J stent placement. Postoperatively, he developed hematuria, a right medial thigh hematoma, fever, and abnormal coagulation parameters, including prolonged activated partial thromboplastin time (APTT). Diagnoses: The diagnosis of AHA was confirmed based on prolonged APTT, markedly reduced FVIII:C, and detection of a factor VIII inhibitor. Additionally, the patient had a complicated urinary tract infection caused by multidrug-resistant F.odoratum , which preceded the onset of AHA. Interventions: Doxycycline was administered to treat the catheter-associated urinary tract infection caused by F.odoratum . Hemostatic control was achieved with activated prothrombin complex concentrate. Immunosuppressive therapy for AHA included dexamethasone and cyclophosphamide. Outcomes: At discharge, bleeding had resolved, APTT normalized, FVIII activity returned to normal levels, the FVIII inhibitor was undetectable, and the infection was successfully controlled. Lessons: AHA is a rare but potentially life-threatening condition. Early recognition, prompt treatment, and identification of underlying triggers are crucial to reducing mortality and improving outcomes. This is the first reported case of AHA associated with F. odoratum infection. Clinicians should consider this pathogen in patients with long-term indwelling urinary catheters who present with unexplained infections or bleeding diatheses.