Pediatric renal abscess: a 12-year single-center retrospective analysis

Pediatric renal abscess is an uncommon but serious complication of urinary tract infection, often characterized by nonspecific symptoms and delayed diagnosis.

We retrospectively analyzed 69 children with radiologically confirmed renal abscesses treated between November 2012 and February 2024. Clinical characteristics, laboratory findings, imaging results, management, and outcomes were evaluated across different age groups.

The median patient age was 24.0 months (IQR 7.3-66.8). There was a marked male predominance in infants (1-24 months) versus a female predominance in children over 60 months, with fever present in 98.6% of cases. Diagnosis was confirmed in all patients by contrast-enhanced CT or MRI, which revealed a mean attenuation difference of 28.8 ± 8.0 HU between the abscess and renal parenchyma; ultrasound sensitivity was 79.7%. Urine cultures were positive in 33.3% of cases, predominantly for Escherichia coli. Notably, vesicoureteral reflux was detected in 52.6% of evaluated patients. While surgical intervention was required in only 7.2% (5/69), these patients had a significantly higher rate of acute kidney injury compared to the conservative group (60% vs. 3.1%; P = 0.0018). The median hospital stay was 12.0 days (IQR 9.0-15.0) and was significantly prolonged in patients with left-sided or bilateral involvement (adjusted P = 0.032 and 0.033, respectively).

Most pediatric renal abscesses can be successfully managed conservatively. Vesicoureteral reflux is common, and acute kidney injury is markedly more frequent among children who require surgical treatment.