Factors associated with Renal Scarring in Children with a First Episode of Febrile Urinary Tract Infection

ABSTRACT

PURPOSE: Development of renal scarring is associated with delayed diagnosis and treatment of urinary tract infection(UTI). This study was performed to clarify how soon treatment should be started to inhibit renal scarring after onset of UTI and the factors associated with renal scarring in children with a first episode of febrile UTI. METHODS: We retrospectively reviewed 163 patients with a first episode of febrile UTI under the age of 2 years from April 2000 to April 2004. All patients had a DMSA renal scan and voiding cystourethrogram done in the diagnostic period, 6 months after which a follow-up renal scan was done. After patients were divided into 2 groups according to the duration of fever prior to start of treatment, the duration of fever after start of treatment, and total duration of fever, initial and follow-up DMSA scan findings were analyzed among the different groups. We compared the factors associated with renal scars between the groups with and without renal scars. RESULTS: The initial DMSA renal scan identified abnormal finding in 23% of the patients who were treated 24 hr prior to treatment. Renal scars developed in 34% of patients with remission of fever 48 hr after treatment. The risk for renal scars was significantly higher in children who had total duration of fever >72 hr(67%) than in those with shorter duration(19%). In children with renal scars, VUR was most highly associated with an increased risk of renal scar formation. CONCLUSION: Although children with a first episode of febrile UTI are treated within 24hr after onset of the fever, renal damage cannot be prevented completely and it is mainly associated with VUR.