Emphysematous Pyelonephritis: A Twelve-year Review in A Regional Centre

Objective: To examine outcomes and prognostic features of patients admitted with emphysematous pyelonephritis (EPN) at a regional tertiary centre. Materials and Methods: Nineteen patients with EPN were identified between January 2007 and December 2019. Patients were grouped into two "mild" (grade I or II); and "severe" (grade III or IV) based on their Huang and Tseng classification. The two groups were compared using Fisher's Exact tests to determine prognostic features associated with poor outcome, defined as extensive surgical intervention or death. Results: Thirteen patients had mild disease and six patients had severe disease. 69% of patients had ureteric obstruction, 58% were diabetic, 26% were thrombocytopaenic, and there was a female predominance (12:7). Poor outcomes were significantly more common in patients with severe disease (83%), versus mild disease (8%) (p<0.0001). Half of the patients managed with sole medical management died (two of four patients) and only two patients required escalation to extensive surgical management, both of whom survived. Overall mortality during admission was 19%; encompassing three of six patients with severe disease (50%) and one of thirteen patients with mild disease (8%). Conclusion: EPN is dangerous, requiring prompt recognition and intervention, and is of increasing importance given the aging population and increased prevalence of comorbidities associated with the disease. This study of the largest recorded cohort of patients with EPN in Australia it was found that poor outcomes were significantly more common in patients with high radiological-grade disease, and severe thrombocytopaenia.