Prediction of Bacterial Etiology in Pediatric Patients with Acute Epididymitis: A Comparison of C-Reactive Protein and Urinalysis in Terms of Diagnostic Accuracy

Background/Objectives: We aimed to determine the proportion of bacterial etiology in pediatric acute epididymitis (AE) and to compare the predictive accuracy of C-reactive protein (CRP) and urinalysis. Methods: Pediatric patients diagnosed with AE in National Taiwan University Hospital from 2009 to 2018 were retrospectively identified. Patient profiles, including clinical symptoms, physical findings, laboratory data, and treatment types, were collected. Patients were categorized into acute bacterial epididymitis (ABE) or acute non-bacterial epididymitis (ANBE) groups based on the presence or absence of bacterial growth in urine cultures. The primary endpoints were the proportion of patients with ABE and those who received antibiotic therapy. The secondary endpoint was to assess the diagnostic accuracy of CRP and urinalysis for ABE. Results: The final cohort comprised of 289 patients, of whom 216 (74.7%) received antibiotics. Urine culture was obtained for 167 (57.8%) patients, and 52 (31.1%) were positive for a bacterial source. The median CRP and positive rate for urinalysis were significantly higher in the ABE group compared to the ANBE group (CRP: 3.68 vs. 0.25 mg/dL; p < 0.001; urinalysis: 41% vs. 23%; p = 0.005). Multivariate analysis revealed that elevated CRP was significantly associated with AE (odds ratio [OR], 61.96; p < 0.001), whereas positive urinalysis was not (OR, 2.09; p = 0.33). The area under the receiver operating characteristic curves for CRP was higher than that for urinalysis (0.82 vs. 0.72). Conclusions: Serum CRP proved to be a more accurate and reliable tool than urinalysis for predicting pediatric ABE. This could provide guidance to practitioners when prescribing antibiotics in the future.