Complicated pyelonephritis associated with chronic renal stone disease

Area of Science:

• Radiology
• Nephrology
• Urology

Background:

• Complicated pyelonephritis, particularly xanthogranulomatous pyelonephritis (XGP) and emphysematous pyelonephritis (EPN), can present with atypical imaging findings.
• These conditions are often associated with chronic nephrolithiasis (kidney stones).
• Distinguishing these infections from renal masses and malignancies is clinically important.

Purpose of the Study:

• To review the imaging manifestations of XGP and EPN in patients with chronic renal stones.
• To provide differentiating features to aid radiologists in suspecting these infections.
• To highlight their potential to mimic other renal diseases and malignancies.

Main Methods:

• Retrospective review of 13 adult patients (6 with XGP, 7 with EPN) with chronic nephrolithiasis.
• Analysis of computed tomography urography (CTU) including unenhanced, parenchymal, and excretory phases.
• Comparison with conventional radiography, ultrasound (US), and magnetic resonance imaging (MRI) when available.

Main Results:

• Imaging findings of XGP and EPN in the context of chronic kidney stones were analyzed.
• Specific imaging characteristics that may suggest XGP or EPN were identified.
• The study aimed to provide radiologists with tools to differentiate these entities from other renal pathologies.

Conclusions:

• XGP and EPN should be considered in pyelonephritis cases associated with untreated kidney stones, especially with atypical presentations or ineffective therapy.
• Radiologists play a key role in differentiating these rare infections from benign or malignant lesions.
• A multidisciplinary approach is essential for managing these complex cases and avoiding unnecessary radical surgeries.