Association Between Abscess Size, Inflammatory Markers, and the Need for Drainage in Renal Abscesses

Renal abscesses represent a serious complication of urinary tract infections, with management decisions often being guided by abscess size and clinical parameters. However, there is no universally accepted size threshold for intervention, and the role of inflammatory markers such as white blood cell count (WBC) and C-reactive protein (CRP) in guiding treatment remains uncertain. We aimed to evaluate the relationship between abscess size, inflammatory markers, and the need for drainage in patients with renal abscesses treated in a tertiary urology clinic.

A retrospective analysis was conducted on 103 adult patients diagnosed with renal abscesses between 2020 and 2025. Patients were categorized into two groups based on abscess size: Group A (<50 mm) and Group B (50 mm).

The cohort included 59 females and 44 males, with a mean age of 60.5 years. Computed tomography was used for diagnosis in 55.3% of cases. The most common comorbidities were hypertension (46.6%) and diabetes mellitus (40.8%). Microbiological cultures most frequently identified Escherichia coli (38.3%) and Klebsiella spp. (21.7%). Antibiotic resistance was highest to ampicillin (79.5%), while amikacin (5.8%) and piperacillin/tazobactam (6.2%) showed the lowest resistance rates. Conservative antibiotic therapy was effective in 43 patients (42.7%), whereas 60 patients (58.3%) required percutaneous drainage. Abscess size was associated with invasive intervention, with 88.1% of drained abscesses measuring ≥50 mm compared to 9.1% in the conservatively managed group (p < 0.001). Patients with larger abscesses had significantly lower haemoglobin levels (p = 0.003), while no significant differences were observed in WBC or CRP levels.

Abscess size was associated with the need for drainage, supporting its role in clinical decision-making. In contrast, inflammatory markers such as WBC and CRP showed limited value in predicting the need for intervention in this cohort. These findings should be interpreted in the context of the retrospective design.