[Vesicoureteral reflux and renal scarring]

Reflux nephropathy is an acquired focal renal scarring due to the combination of vesicoureteral (VUR) and intrarenal reflux (IRR) associated with urinary tract infections (IUT) and/or permanently high intravesical pressure. Up to 30-60% of children with VUR and a history of symptomatic IUT have renal scarring at the time of their initial studies. The onset of renal scarring usually occurs early in life, usually before age five years and most frequently before three years of age. Girls are at greater risk for developing reflux nephropathy, because of increased incidence of IUT. Reflux nephropathy is different from a diffuse congenital renal scarring (hypo-dysplasia), which is usually discovered antenatally or during infancy in boys with severe VUR. Without serial follow-up (ultrasonography, intravenous pyelourography, 99mTc-DMSA scan) from birth, it is not always possible to differentiate congenital renal scarring from reflux nephropathy. In contrast to reflux nephropathy, congenital renal scarring cannot be prevented. 99mTc-DMSA renal scintigraphy is the gold standard technique (sensitivity 92%, specificity 98%) for the diagnosis of reflux nephropathy, but ultrasound is a good modality to monitor kidney growth over time. Reflux nephropathy and hypodysplasia are the main causes of chronic renal failure and arterial hypertension in children and adolescents in our country. The long-term follow-up of children with reflux nephropathy is mandatory, since its complications may take 10 to 20 years to develop. Uncontrollable arterial hypertension and proteinuria are the predictors of poor prognosis. The selective use of angiotensin converting enzyme inhibitors and/or angiotensin II receptor blockers is the efficient antihypertensive therapy, which also modify intrarenal haemodynamics and can preserve renal function.