Delayed treatment of the first febrile urinary tract infection in early childhood increased the risk of renal scarring

Aim: This study evaluated the controversial relationship between the duration of fever before treatment initiation (FBT) for a febrile urinary tract infection (UTI), with renal scarring based on dimercaptosuccinic acid scintigraphy (DMSA) findings. Methods: The inpatient records of 148 children under two years of age with a first episode of febrile UTI were analysed. Acute and repeat DMSA findings, and clinical and laboratory parameters were evaluated. Results: Acute DMSA showed that 76 of the 148 children with a febrile UTI had renal lesions: 20 were mild, and 56 were moderate or severe. Repeat DMSA showed renal scarring in 34 patients. The only factors associated with the development of renal scars in the repeat DMSA were FBT of more than 72 hours, the presence and severity of vesicoureteral reflux and increased procalcitonin levels and absolute neutrophil counts. Multiple regression analysis showed that an FBT above 72 hours was the only significant factor that predicted renal scars. Conclusion: Delay in treatment initiation of 72 hours or more was a risk factor for permanent renal scars after the first episode of febrile UTI. Other associated factors were increased procalcitonin and absolute neutrophil count on admission and the presence and severity of vesicouretal reflux.