Acute pyelonephritis (APN) with acute kidney injury is one of the common urological emergencies needing intensive care and monitoring. Initial evaluation regularly involves a non-enhanced computed tomography (NECT), followed by an emergency Double J (DJ) stenting to decompress the pelvicalyceal system and facilitate urinary drainage. Many a time, once renal function improves, due to financial constraints, these stents are most often removed under local anaesthesia in outpatient settings. Though most patients recover well after stent removal, a smaller subset of patients develop recurrent symptoms needing readmission. Necrosed papillae, which form infection-prone foci in the lower calyces, are frequently observed in such cases. Our study investigates the increasing incidence of these findings and emphasizes the growing need for a relook flexible ureteroscopy in preventing bacterial persistence and reinfections.

This prospective study was performed on patients who were treated with cystoscopy and DJ stenting for APN from August 2023 to July 2024. A relook flexible ureteroscopy (Flexi URS) was performed 4–6 weeks after the initial DJ stenting. Experienced urologists with at least 3 years of experience in flexible ureteroscopy performed all procedures. Necrosed papillae, if present, were removed. The findings were documented and analyzed.

Among 303 enrolled patients, 229 underwent DJ stenting followed by relook Flexi URS. Of these, 127 were female and 102 males, with a mean age of 60.25 ± 12.92 years in males and 49.27 ± 11.46 years in females (p = 0.0001). The mean baseline serum creatinine was 2.57 mg/dL, and the mean eGFR was 32.8 mL/min/1.73 m². A total of 199 patients (65.6%) were in stage 3 or higher of chronic kidney disease. Hydroureteronephrosis (HUN) was noted in 160 patients (69.7%), 116 of whom (72.5%) exhibited necrosed renal papillae within the pelvicalyceal system (PCS). Among 69 patients (30.1%) without HUN, 28 (40.6%) also had necrosed papillae. Flexi URS successfully retrieved necrosed papillae in 97 patients. Significant improvements were observed in total leukocyte count, serum creatinine, and eGFR after DJ stenting (p < 0.05) and at 6 months post-relook Flexi URS. Serum creatinine reduced from 2.57 mg/dL to 1.4 ± 0.7 mg/dL (p < 0.05), indicating enhanced renal function and reduced reinfection risk.

A significant proportion of diabetic APN patients harbour necrotic papillae, which, if untreated, lead to bacterial persistence and recurrent infections, worsening renal outcomes. Relook flexible ureteroscopy is effective in clearing necrosed fragments, reducing reinfection rates, and preventing renal function decline. Missing the boat on routinely addressing these necrotic foci leads to persistent gaps in post-DJ stenting management, emphasizing the need to incorporate this intervention into standard clinical protocols to improve patient outcomes.