Prolonged suppressive antibiotic therapy for inferior vena cava filter infection following emphysematous pyelonephritis and cystitis: a case report

Introduction and importance: Infections of inferior vena cava (IVC) filters are rare. The authors present a case of IVC filter infection following concurrent emphysematous urinary tract infections that was finally treated with prolonged suppressive antibiotic therapy (PSAT). Case presentation: A 68-year-old man with pemphigoid and type 2 diabetes mellitus, who had undergone IVC filter placement, was transferred with decreased consciousness, respiratory failure, and hypotension. Computed tomography revealed gas in the left renal parenchyma and bladder wall, suggesting a diagnosis of concurrent emphysematous pyelonephritis and cystitis. While blood and urine cultures were positive for extended-spectrum beta-lactamase-producing Escherichia coli, and the patient's general condition improved with proper antibiotic therapy, bacteremia persisted until day 10 from symptom onset. After ruling out abscesses and infectious endocarditis, the cause of persistent bacteremia was suspected to be IVC filter infection. As the IVC had been placed 12 years before, the authors did not remove it to avoid complications. PSAT with sulfamethoxazole-trimethoprim was continued after 6 weeks of intravenous antibiotic therapy. The patient had an uneventful course over the year following hospital discharge. Clinical discussion: PSAT is considered for device-related infections in patients with cardiac assist devices and artificial joints when the infection flares up or recurs even after antibiotic treatment of an adequate duration. There is no consensus regarding the optimal duration of antimicrobial therapy for IVC filter infections. Conclusion: Infections of implanted devices, such as IVC filters, secondary to severe infections can cause persistent bacteremia. PSAT may be an alternative option to treat IVC filter infection, when the IVC filter is considered difficult to remove.