Deriving a management algorithm for emphysematous pyelonephritis: Can we rely on minimally invasive strategies or should we be opting for earlier nephrectomy?

Abstract

To analyse the incidence and management of emphysematous pyelonephritis (EPN) in North West London and examine factors that influence immediate and 6-month outcomes with the aim of guiding future management. This work analyses EPN cases from the London North West Healthcare NHS Trust from October 2006 to July 2015 (population≈850,000). Diagnosis and stage were confirmed by computed tomography (CT). Demographic, clinical, biochemical and microbiological characteristics were assessed. Treatment modalities were medical management, minimally invasive management (MIM) and surgical. Immediate and 6-month outcomes were analysed. Thirteen cases were identified (f=8, m=5) from 5525 CT scans. EPN occurred in patients with diabetes mellitus (n=11, 84.6%), hypertension (n=10, 76.9%) or urinary tract calculi (n=7, 53.85%). Unilateral EPN occurred predominantly (n=11, 84.6%); 46.1% (n=6) were class 1 or 2 and 53.8% (n=7) class 3 or 4. Escherichia coli was most commonly cultured (n=5, 38.46%). All patients received antibiotics, and ten cases required MIM. Two patients had a delayed nephrectomy, both survived. Mortality was 15.4% (n=2, grade 1 and 3a), both died acutely post-MIM, neither underwent emergency nephrectomy. At 6months, eight patients had ongoing renal impairment. No specific poor prognostic factors were identifiable. Patients with low-grade EPN may also have a high mortality rate. In the two cases who died, earlier consideration for nephrectomy may have been prudent. It may be beneficial to have a low threshold for prompt emergency nephrectomy in severe cases and where MIM treatment has failed. We suggest a management algorithm to guide clinicians and minimise mortality.