Vesicoureteral Reflux and Renal Scarring

Abstract

Vesicoureteral reflux (VUR) is the retrograde flow of urine from the bladder to the kidneys. This retrograde flow of urine, while the norm in some animals, is not normal in humans. 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 uro- pathy or neurogenic bladder (secondary VUR). Most cases with VUR are diagnosed after urinary tract infection (UTI). The common belief has been that the presence of VUR increases the risk of UTI and the two together cause renal scarring (reflux nephropathy), which may lead to hypertension, toxemia of pregnancy, chronic renal insufficiency and even end-stage renal disease (ESRD). The traditional management has included a prompt treat- ment ofUTI and long-term antimicrobial prophylaxis until the resolution of VUR. Surgical correction has been advo- cated in those with high grade VUR, recurrent UTI in spite of antimicrobial prophylaxis, ornon-compliance withmed- icalmanagement.Over the years,many studies have debat- ed if one treatment modality is superior to another in preventing renal injury, withmost of the studies concluding that the long-term outcome with one intervention is no better than the other.However, the exact role ofVUR in the development of renal injury has been difficult to elucidate. Recently, new data have been published regarding the het- erogeneity of the secondary effects of reflux, and the role played by voiding dysfunction and/or constipation in the resolution of VUR or the frequency of UTI. In this chapter, we will provide an overview of the important issues con- cerning primary VUR. This will include: the embryology and anatomy of the ureterovesical junction; the current modalities for diagnosis and management; and a review of current controversies and emerging consensus concerning the role of primary VUR in the pathophysiology of renal scarring.