An experience in the diagnosis and treatment of difficult-to-treat complicated urinary tract infection

A 29-year-old female presented with recurrent fever, lumbar pain, pyuria, and renal masses. Imaging revealed structural abnormalities of the right kidney, demonstrating the classical "Bear's Paw sign", with angular or linear calculi. Renal hemodynamic scintigraphy suggested that the right kidney was non-functional. Despite adequate anti-infective treatment, the patient continued to exhibit persistent pyuria with mildly increased inflammatory markers. Reviewing the literature and consulting multidisciplinary specialists, a therapeutic regimen centered on radical right nephrectomy was ultimately determined. Histopathology identified xanthogranulomatous pyelonephritis (XGP), establishing the final diagnosis. The prognosis of XGP was improved over a 6-month follow-up period. This study summarizes the key points of XGP diagnosis to improve the general physicians' awareness, facilitating earlier diagnosis, treatment, and rehabilitation.