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

PURPOSE: 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.
METHODS: 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.
RESULTS: 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 6 months, eight patients had ongoing renal impairment. No specific poor prognostic factors were identifiable.
CONCLUSIONS: 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.