Vesicoureteral Reflux and Renal Scarring in Children

Abstract

Vesicoureteral reflux (VUR) is the most common congenital anomaly of the urinary tract. The gold standard for diagnosing VUR is a voiding cystourethrogram (VCUG). According to the International Reflux Grading Scheme, the severity of VUR is classified as grade I–V. It is diagnosed in 30–40 % of children with a urinary tract infection (UTI). VUR may be an isolated abnormality (primary VUR) or it may occur in association with other congenital anomalies of the kidney and urinary tract (CAKUT), including renal dysplasia and obstructive uropathy. VURmay also be noted secondary to bladder dysfunction such as neurogenic bladder or other obstructive anomalies (e.g., posterior urethral valves) (secondary VUR). An increasing number of children with VUR are being diagnosed during follow-up for antenatally diagnosed renal abnormalities and no preexisting history of UTI. Renal scarring associated with VUR is called reflux nephropathy (RN). RN is categorized as “congenital,” which is a result of abnormal renal development leading to focal renal dysplasia, or “acquired” as a result of pyelonephritis-induced renal injury. Complications of RN in pediatric patients include proteinuria, hypertension, and end-stage renal failure (ESRF). The management of VUR has been driven by the belief that the risk of VUR and UTIassociated renal injury is decreased by long-term antimicrobial prophylaxis or surgical correction of VUR. Over the years, many studies have assessed if one treatment modality is superior to another in preventing kidney injury, with most concluding that the long-term outcome with one intervention is no better than the other. Recently, surveillance with no intervention, particularly for low-grade VUR, has been proposed as another option, which has generated questions on the usefulness of routinely diagnosing VUR after UTI, particularly if the clinical presentation is typical and renal ultrasound is normal. This argument forms the basis of various recent recommendations on the management of children after first UTI.