Emphysematous pyelonephritis-related delayed abdominal wall necrotizing fasciitis

Rationale: Emphysematous pyelonephritis (EPN) is a severe, gas-forming renal infection typically associated with diabetes mellitus. Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection with significant morbidity. Although concurrent EPN and NF have been described, delayed NF arising years after previously treated EPN is exceedingly rare. This report highlights a unique case of abdominal wall NF secondary to a chronic infectious pathway originating from prior EPN. Patient concerns: A 55-year-old woman with poorly controlled type II diabetes mellitus initially presented with right flank pain, fever, and malaise due to EPN. Two years later, she developed progressive swelling, pain, and discoloration over the right lower abdominal wall, hip, and gluteal region. Diagnoses: Imaging at initial presentation confirmed right-sided EPN with hydronephrosis requiring percutaneous drainage. At the delayed presentation, computed tomography revealed gas-forming inflammation extending from the right kidney through the retroperitoneum to the abdominal wall and gluteal region. A retained double-J stent and a suspected fistulous communication suggested a chronic infectious source leading to NF. Interventions: The patient underwent emergent surgical debridement, followed by serial debridements (eight sessions), broad-spectrum antibiotics, negative-pressure wound therapy, and hyperbaric oxygen therapy. After achieving healthy granulation tissue, wound closure was accomplished using an adhesive-based shoelace device. Outcomes: The infection gradually resolved, and the wound healed completely after staged closure. The patient recovered fully and was discharged after 58 days of hospitalization. Lessons: Clinicians should remain alert to the possibility of chronic or delayed soft tissue infection in patients with prior EPN, particularly when indwelling urinary stents remain in place. Long-term surveillance is crucial to confirm definitive source control and to prevent catastrophic complications such as NF.