Predictive Factors of Renal Scarring in Children with Acute Urinary Tract Infection

Baik, Jun Hyun; Park, Young Ha; Hwang, Sung Su; Jeon, Jung Su; Kim, Sung Hoon; Lee, Seong Yong; Chung, Soo Kyo

Abstract

PURPOSE
The purpose of this study was to evaluate the usefulness of 99mTc DMSA scintigraphy on the dignosis of a renal scar in children with urinary tract infections. MATERIALS AND METHODS: Eighty three patients were included in this study, who were diagnosed as the urinary tract infection on the basis of symptom, urinalysis and urine culture. 99mTc DMSA scintigraphy and voiding cystoureterography were performed within 7days before the treatment in all patients. We classified the scintigraphic findings as follows: 1; a large hypoactive upper or lower pole. 2; a small hypoactive area. 3; single defect resulting in localized deformity of the outlines. 4; deformed outlines in a small or normal sized kidney. 5; multiple defects. 6; diffuse hypoactive kidney without regional impairment. Follow-up scintigraphy was done at least 6 months after the initial study. When the abnormality on the initial scintigraphy was not completely resolved on the follow-up scan, the lesion was defined as containing a scar. RESULTS: One hundred and fifteen renal units of 166 units (69.3%) showed abnormal findings on the DMSA scintigraphy. 65 units (56.5%) was diagnosed as containing renal scars on follow-up scintigraphies. Incidences of renal scar among renal units showing pattern 3, 4 and 5 on the initial scan was 75%, 78% and 78%, respectively. Whereas many of renal units showing 1, 2 and 6 pattern were recovered (65%, 76%, 50%). Sensitivity, specificity and accuracy of pattern-based DMSA scintigraphic findings on the diagnosis of renal scar was 76.9%, 85.1% and 81.9%, respectively. VUR was significantly associated with the renal scar when the initial DMSA shows unrecoverable findings (pattern 3, 4, 5). Odds ratio of the renal scar in a kidney showing unrecoverable initial scintigraphic findings was 19.1. Odds ratio in a kidney with mild or moderate-to-severe VUR was 3.5 and 14.4 respectively. CONCLUSION: In the urinary tract infection, renal scar was significantly developed in a kidney showing unrecoverable findings on the initial DMSA scan and VUR on voiding cystoureterography.