Clinical Profile and Immediate Outcome of Management of Emphysematous Pyelonephritis: A Matched Case-Control Study

Abstract

Introduction: Emphysematous pyelonephritis (EPN) is a severe, life-threatening complication of acute pyelonephritis (APN), predominantly affecting diabetic patients. Differentiating EPN from non-emphysematous APN based on clinical and biochemical parameters remains challenging, and delayed diagnosis may lead to poor outcomes. Optimal management strategies for EPN remain controversial, particularly in resource-limited settings. Aim of the Study : To compare the clinical and biochemical profiles of EPN and non-EPN patients and to evaluate management strategies and short-term outcomes. Methods: This retrospective matched case-control study was conducted in the nephrology department of a tertiary care hospital from January 2018 to January 2022. A total of 35 consecutive patients with EPN were enrolled as cases. For each case, one control with non-emphysematous APN was individually matched by age and gender from patients admitted during the same study period. Clinical features, laboratory parameters, microbiological findings, management approaches, and outcomes at discharge were analyzed using SPSS version 20. Results: Baseline characteristics were comparable between groups. Chronic kidney disease (57% vs. 26%, p = 0.007) and recurrent UTI (45.7% vs. 22.9%, p = 0.044) were significantly higher in non-EPN patients. Clinical features at presentation did not significantly differ; however, pneumaturia was observed only in EPN patients (11% vs. 0%). Among biochemical parameters, random blood glucose (18.79 ± 10 vs. 14.4 ± 6 mmol/L, p = 0.004) and metabolic acidosis (low HCO 3 : 47.1% vs. 38.2%, p = 0.039) were significantly higher in EPN. No significant differences were noted in serum creatinine (p = 0.109) or HbA1c (p = 0.829). E. coli was the predominant pathogen in both groups (75% - 81%). Conservative management was successful in 54% of EPN and 88% of non-EPN cases. Among EPN patients, 37% required open drainage and 9% underwent nephrectomy. Overall survival in EPN was 97%. Conclusion: Based on unadjusted comparisons, initial clinical and laboratory findings alone are insufficient to reliably distinguish EPN from APN; adjusted analyses accounting for baseline differences such as CKD, recurrent UTI, admission glucose, and acidosis are needed to confirm this. The presence of pneumaturia strongly suggests EPN. In resource-constrained settings, open drainage represents an effective kidney-sparing treatment strategy, with emphasis on organ preservation whenever feasible.