Nephromegaly is a significant risk factor for renal scarring in children with first febrile urinary tract infections

Purpose: We determined whether nephromegaly on ultrasound can be used to identify patients with urinary tract infection at increased risk for renal scarring, and we investigated the effect of vesicoureteral reflux on renal scarring. Materials and Methods: We enrolled hospitalized patients with a first febrile urinary tract infection. All patients underwent renal ultrasound and most patients underwent voiding cystourethrography. Renal scarring was assessed using ^99mtechnetium dimercapto-succinic acid renal scintigraphy at least 6 months after treatment. Children with recurrent urinary tract infections before scintigraphy were excluded from the study. Results: A total of 545 children (80 with and 465 without nephromegaly) were enrolled. Infection was more severe in patients with than without nephromegaly. The incidence of renal scarring was significantly higher in patients with nephromegaly (90% vs 32%, p <0.001), in kidneys with nephromegaly (80.5% vs 18.7%, p <0.001) and in kidneys with vesicoureteral reflux (41.5% vs 22.2%, p <0.001). Kidneys with nephromegaly had a greater incidence of reflux. The finding of nephromegaly is associated with a greatly increased likelihood of renal scarring in patients with vesicoureteral reflux. Conclusions: Our results indicate that ultrasound diagnosis of nephromegaly at onset is associated with a high incidence of renal scarring, and identification of nephromegaly at onset and vesicoureteral reflux are significant risk factors for renal scarring in children with a first febrile urinary tract infection. Nephromegaly is associated with an increased frequency of vesicoureteral reflux and increased likelihood of renal scarring in patients with reflux.