Emphysematous Pyelonephritis Caused by Citrobacter freundii in a Patient with Type 2 Diabetes and Neurogenic Bladder

Emphysematous pyelonephritis (EPN) is a rare, life-threatening complication of upper urinary tract infections that is characterized by the presence of gas in the renal parenchyma and perirenal space. It commonly occurs in diabetic patients. Escherichia coli are the most common causative organisms, with few reports implicating Citrobacter freundii as the etiologic agent in EPN. A 57-year-old woman with diabetes and neurogenic bladder visited at our department with confused mentality, myalgia, and general weakness. Further investigation revealed that the patient suffered from unilateral EPN with sepsis caused by C. freundii. The patient's condition was improved considerably with percutaneous drainage and use of intravenous antibiotics for several weeks. However, renal function eventually deteriorated to permanent renal failure, which required hemodialysis. In conclusion, C. freundii may be the causative pathogen of EPN in a patient with type 2 diabetes and neurogenic bladder.