Vesicoureteral reflux (VUR) is the retrograde passage of urine from the bladder into the upper urinary tract.
●VUR is divided into two categories based on the underlying pathogenesis:
•Primary VUR, the most common form of reflux, is due to incompetent or inadequate closure of the ureterovesical junction (UVJ) that contains a segment of the ureter within the bladder wall (intravesical ureter).
•Secondary VUR is a result of abnormally high voiding pressure in the bladder that results in failure of the closure of the UVJ during bladder contraction.
●Primary VUR occurs in approximately 1 percent of newborns. However, there is a significant rate of spontaneous resolution with growth, especially for patients with low-grade reflux (Grades I and II).
•Prenatally as antenatal hydronephrosis on prenatal ultrasound.
•Postnatally typically after an initial febrile illness or UTI, or, less commonly, after family screening of an index case.
●The diagnosis of VUR is based upon the demonstration of reflux of urine from the bladder to the upper urinary tract by either contrast voiding cystourethrogram (VCUG) or radionuclide cystogram (RNC).
●In our practice, the following diagnostic approaches are used:
•Prenatal presentation – An initial postnatal renal ultrasound is performed in all patients who present with prenatal hydronephrosis. A VCUG is performed in infants with persistent postnatal abnormal ultrasound findings or who develop a urinary tract infection (UTI).
•Postnatal presentation – VCUG is obtained in children after a first febrile or symptomatic UTI if they are not toilet trained, have an anomaly on renal ultrasound, have hypertension or poor growth, or a have combination of temperature ≥39°C (102.2°F) and a pathogen other than Escherichia coli. Other factors to consider are family preference and evaluation of compliance regarding medical care after discussion with the family.
●VCUG is the imaging test of choice to diagnose the presence and establish the degree of VUR. The severity of VUR is dependent upon the degree of retrograde filling and dilation of the renal collecting system. Established grading systems based upon VCUG findings are used to measure the severity of VUR.
●Children with VUR are at risk for recurrent febrile or symptomatic UTIs, especially those with more severe VUR.
●Loss of renal parenchyma is a common finding in patients with VUR. It may lead to decreased renal function, and in some affected individuals with severe bilateral involvement to end-stage renal disease (ESRD). Reduction in renal parenchyma is caused by the following mechanisms:
•Acquired scarring is caused by renal parenchymal infection, which can occur in those with any grade of reflux, but is more common in those with higher VUR grades (III to V).
•Congenital renal hypodysplasia.
●We suggest the following evaluation be performed in all children with VUR :
•Medical evaluation including measurements of height, weight, and blood pressure, and identifying any patient with symptoms indicative of voiding dysfunction.
•Serum creatinine if there is bilateral involvement or in a patient with a solitary kidney.
•Renal imaging with renal ultrasound and in selected patients, dimercaptosuccinic acid (DMSA) renal scan.
•We suggest initial selective screening for VUR in younger siblings or offspring of the index case.
From Up To Date: Clinical presentation, diagnosis, and course of primary vesicoureteral reflux