Material and Method: A prospective study was conducted in 67 children with the first episode of UTI at the Department of Pediatrics, Faculty of Medicine Siriraj Hospital between 2008 and 2010. To assess for renal damage, dimercaptosuccinic acid (DMSA) renal scintigraphy was performed at one and six months after the acute episode.

Results: Abnormal DMSA renal scintigraphy was detected in 20 (29.9%) patients. There was no difference in TDT but TRT was different between the patients with normal and abnormal DMSA renal scintigraphy at p-value 0.001. The area under receiver operating characteristic (ROC) curve for TRT was 0.76 (95% confidence interval (CI) 0.64-0.86) at p-value 0.001. The optimal cut-off value for TRT was 22 hours with sensitivity 80.0% (56.3-94.1) and specificity 63.6% (47.8-77.6). In 50 patients with no vesicoureteral reflux (VUR), there was difference in TRT at p-value 0.002. The area under ROC curve for TRT was 0.82 (95% CI 0.69-0.96) at p-value 0.004. The optimal cut-off value for TRT was 25 hours with sensitivity 88.9% (95% CI 51.7-98.2) and specificity 68.4% (95% CI 51.3- 82.5).

Conclusion: TRT at or more than 22 hours predicts renal damage after first episode of UTI. In patients with no VUR, TRT at or more than 25 hours predicts renal damage. DMSA renal scintigraphy in the first episode of UTI should be considered in these patients.

Keywords: DMSA renal scintigraphy, Renal damage, Urinary tract infection