Follow-up evaluation of prenatally recognized vesicoureteric reflux

Diagnosis and management of urinary tract infection and vesicoureteral reflux in the neonate

Urinary tract infection (UTI) is the most common bacterial infection in febrile newborns, particularly those born prematurely and with a low birth weight. Vesicoureteral reflux (VUR) predisposes to UTI and renal scarring. Half of neonates with UTI may have only low-grade fever or no fever. Jaundice in the absence of any other symptoms or signs may be the only clinical manifestation of UTI in neonates. The urinalysis may be negative in a significant number of neonates with UTI. Newborns with UTI have a high incidence of congenital anomalies of kidney and urinary tract anomalies, and hence should undergo renal imaging.

Is antibiotic prophylaxis effective in preventing urinary tract infections in patients with vesicoureteral reflux?

The main concern in the management of children with vesicoureteral reflux (VUR) is the prevention of urinary tract infections and avoidance of renal damage. Medical management has been recommended or preferentially suggested over surgery in all but a few select clinical situations. Prophylactic antibiotics are prescribed routinely in the management of young children with radiological evidence of VUR following an episode of acute pyelonephritis. Prophylaxis is generally maintained until the VUR resolves spontaneously or is corrected surgically. Although the administration of prophylactic antibiotics has been universal in children with VUR, some authors have reported that long-term antibiotic prophylaxis does not fully prevent urinary tract infections or scarring, that antibiotic-related adverse events are known to occur, and that the incidence of pyelonephritis does not increase in spite of prophylactic antibiotic cessation. Recently, four prospective, randomized, controlled trials of antibiotic prophylaxis for preventing pyelonephritis and renal scarring were reported and some placebo-controlled, double-blind prospective studies are ongoing. The goal of this review is to evaluate the treatment of VUR using antibiotic prophylaxis, and its advantages and disadvantages based on appropriate descriptions and studies in the literature.

Postnatal evaluation of infants with an abnormal antenatal renal sonogram

PURPOSE OF REVIEW

Antenatally detected renal abnormalities are frequently encountered. Recommended postnatal evaluation of these infants has evolved to minimize invasive testing while maximizing detection of significant abnormalities.

RECENT FINDINGS

There is a low rate of detectable renal abnormalities in infants with a normal postnatal sonogram at 4-6 weeks of age. Routine prophylactic antibiotics are not indicated in infants with isolated antenatal hydronephrosis. Infants with a multicystic dysplastic kidney and a normal contralateral kidney on renal ultrasound do not require further evaluation. Parents of these children should be counseled on symptoms of urinary tract infections to allow prompt diagnosis.

SUMMARY

All infants with abnormalities on antenatal sonogram should undergo postnatal evaluation with a sonogram after birth and at 4-6 weeks of age. Further evaluation can be safely limited when the postnatal sonogram is normal at 6 weeks of age.

Medical management of vesicoureteral reflux--quiz within the article. Don't overlook placebos

Vesicoureteral reflux (VUR) in children is associated with increased risk of urinary tract infection (UTI). Recurrent UTI in the presence of the VUR is believed to cause renal scarring, which carries a risk of subsequent hypertension, toxemia of pregnancy, and significant renal damage, including end-stage renal disease. The natural history of VUR is to improve or resolve completely with time in most of the patients. The traditional management consists of prompt treatment of UTI, long-term anti-microbial prophylaxis until the VUR resolves, or surgical intervention in those with persistent high grade VUR, recurrent UTI in spite of prophylaxis with anti-microbial agent, allergy to anti-microbial agents, and patient/parent non-compliance with the medical management. Voiding dysfunction and constipation play an important role, and their diagnosis and appropriate management helps reduce the frequency of UTI and promote the resolution of the VUR. Patients with renal scarring need to be monitored for potential complications such as hypertension, proteinuria, and progression of the renal damage. In patients with hypertension and/or proteinuria, angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) are the drugs of choice, because of their reno-protective properties. Recent studies have revealed that there is no convincing evidence that UTI in the presence of VUR predicts renal injury or that the use of long-term anti-microbial prophylaxis or surgical intervention prevents renal scarring or its progression. However, until proven otherwise by a prospective, placebo-controlled, randomized study, it is advisable to err on the side of caution and consider VUR and UTI risk factors for renal scarring and treat each patient on individual basis.

Mild hydronephrosis in newborns and infants: can ultrasound predict the presence of vesicoureteral reflux

The objective of our study was to determine the significance of mild hydronephrosis in newborns and infants as an indicator of vesicoureteral reflux (VUR). The voiding cystourethrography (VCUG) of 573 patients aged 0-18 months with mild, sonographically detected hydronephrosis were reviewed for VUR. Patients with secondary reflux or anomalies making an exact reflux grading impossible were excluded. Normal kidneys, contralateral to hydronephrotic ones, were included. Each kidney was considered separately, forming a total of 1,146 renal units. Mild hydronephrosis was defined as an anteroposterior diameter of the renal pelvis of 0.5-1.5 cm without caliectasis. The International Grading System was used to grade VUR. Seven hundred and thirty-six kidneys had mild hydronephrosis. VUR occurred in 189 out of 736 (25.7%) of these kidneys, and in 108 out of 410 (26.3%) non-distended kidneys, contralateral to hydronephrotic ones (p=0.806). No statistical differences in the frequency of VUR and dilatation were found between the subgroups of patients with and without infection, except for a higher grade of reflux in the group with infection. The frequency of VUR in mildly dilated kidneys was not significantly different from that in non-distended ones. There was a poor correlation between VUR and mild hydronephrosis. The latter should not be considered in itself an indication for VCUG in asymptomatic neonates and infants.

Vesicoureteral reflux

Vesicoureteral reflux, the abnormal flow of urine from the bladder into the ureter, is one of the most common congenital anomalies found in children. The association of vesicoureteral reflux with urinary tract infections and renal scarring has important clinical implications. New insights into pathogenesis and new surgical techniques are changing the approach to the management of this disorder.

Clinical course of prenatally detected primary vesicoureteral reflux

The purpose of this study was to report the clinical course of medium-long-term follow-up of children with prenatally detected vesicoureteral reflux (VUR). Between 1986 and 2004, 53 (41 males) children with VUR detected by investigation of prenatal hydronephrosis were followed up for a mean time of 66 months (range: 6-200 months). Newborns were investigated by ultrasound, voiding cystourethrogram (VCUG) and DMSA scan. Follow-up clinical visits were performed at 6-month intervals. After 24 months patients were investigated by conventional VCUG or direct isotope cystogram. Survival analysis was performed in order to evaluate the resolution of the reflux. Differences between subgroups (mild vs moderate/severe reflux) were assessed by the two-sided log rank test. Thirty (58%) infants presented bilateral VUR, for a total of 83 renal units. There was a predominance of severe reflux (54%). Renal damage was detected in 33.7% of the units on first renal scan. There was a significant correlation between severe reflux and renal damage scars (RR=3.4, 95% confidence interval [CI], 1.4-8, p=0.002). Forty-seven patients were treated with continuous prophylaxis. One patient developed systolic hypertension. Urinary tract infection occurred in 12 (25%) children conservatively managed. VUR resolution was evaluated in 56 renal units. Spontaneous resolution was observed in 25 units (45%). At 48 months after diagnosis, 75% of the cases of mild reflux (I-III) and 37% of severe reflux (IV-V) had resolved (log-rank, 5.6, p=0.017). There was an improvement of nutritional parameters between admission and the end of follow-up. In conclusion, the clinical course of prenatally detected VUR followed up on a medium-long-term basis is relatively benign. Our study corroborates the results obtained in other series of infants with reflux that emphasized the heterogeneity of this disorder.

Freqüência de desaparecimento do refluxo vésico-ureteral de graus I a III em pacientes pediátricos

OBJETIVOS: avaliar a freqüência do desaparecimento do refluxo vésico-ureteral (RVU) primário de graus I a III em crianças e correlacionar com idade no diagnóstico, sexo, grau e lateralidade. MÉTODOS: estudo retrospectivo de 34 crianças com RVU diagnosticado por uretrocistografia miccional (UCM). Cinco pacientes eram meninos (mediana: um ano e seis meses) e 29 meninas (mediana: três anos) O exame controle pela UCM ou cistografia foi realizado em intervalos de 12 a 24 meses. Na análise das variáveis utilizou-se a curva de sobrevida de Kaplan-Meier. RESULTADOS: o desaparecimento do RVU ocorreu em 52,9% dos pacientes. Comparando faixas etárias não houve diferença estatística. Nos meninos o desaparecimento do RVU ocorreu na mediana de 24 meses e nas meninas, de 60 meses. Houve diferença estatística entre os sexos (p = 0,02). Houve desaparecimento do RVU em 80% dos pacientes com RVU de grau I (mediana: 25,5 meses), 66,6% de grau II (mediana: 48 meses) 40% de grau III (mediana: 60 meses); em 21% no bilateral (mediana: 48 meses) e 75% no unilateral (mediana: 28,5 meses). Houve diferença estatística entre os graus de RVU (0,02) e lateralidade (p = 0,05). CONCLUSÕES: o desaparecimento do RVU ocorreu no sexo masculino, nos graus I ou II e unilateral.

Severe vesicoureteral reflux and chronic renal failure: a condition peculiar to male gender? Data from the ItalKid Project

Primary vesicoureteral reflux (VUR), one of the principal causes of chronic renal failure (CRF), occurs as a result of two distinct and sex-related mechanisms: congenital renal hypoplasia, which is prevalent in males, and acquired renal scarring in females. We used data from the ItalKid Project, a prospective population-based CRF registry of patients undergoing conservative treatment, to evaluate the gender distribution and severity of primary VUR, the age at diagnosis, and the diagnostic and therapeutic methods adopted in children with CRF. The prevalence of males (77.5%), the severity of VUR (grade IV-V), and the early age at diagnosis (18% prenatally) seem to suggest that congenital renal damage is the major cause of pediatric CRF.

The natural history of neonatal vesicoureteral reflux associated with antenatal hydronephrosis

PURPOSE

In an attempt to evaluate the natural history of neonatal vesicoureteral reflux, patients with antenatal history of hydronephrosis and documented reflux in the first 30 days of life were analyzed.

MATERIALS AND METHODS

Between 1993 and 1998, 260 patients with a history of antenatal hydronephrosis were referred for evaluation. Of these patients 31 were diagnosed with unilateral or bilateral refluxing renal units (54 renal units). Patients were treated with a prospective plan of observational therapy and prophylactic antibiotics, and resolution rate was calculated in patients with adequate followup. Reflux grade was correlated with postnatal ultrasonographic findings, urinary tract infections and differential renal function. Outcome analysis of 34 high grade (III to V) refluxing renal units using the Kaplan-Meier survival curves was undertaken with the end point being complete resolution or improvement. Three patients with vesicostomy and 2 who underwent ureteral reimplantation were excluded from analysis.

RESULTS

Reflux was grade I in 5% (33% males), II in 15% (62% males), III in 32% (71% males), IV in 18% (90% males) and V in 30% (100% males) of the patients. Postnatal ultrasound findings correlated poorly with the presence and degree of vesicoureteral reflux. Of 17 patients followed for at least 14 months (average followup 20) there was complete resolution in 60% with grade III, 50% with grade IV and 28% with grade V reflux. Using the Kaplan-Meier estimate there was a 50% chance of improvement (decrease in reflux grade by at least 2 grades) in high grade reflux by age 16 months. Urinary tract infections developed in 8 patients (26%) while on antibiotics. Of 46 renal units in 23 patients evaluated with a renal scan before urinary tract infection, 12 had less than 35% function.

CONCLUSIONS

A normal postnatal ultrasound should not be a basis for excluding the use of cystography. Our Kaplan-Meier estimate shows that high grade reflux does improve and may resolve spontaneously. In addition, renal scarring may be seen with high and low grade reflux in the absence of urinary tract infection but high grade reflux is associated with a higher incidence of infection.

Striking findings concerning the variability in the measurement of the fetal renal collecting system

OBJECTIVE

Using strict thresholds of normality, investigators have reported associations between fetal pyelectasis and aneuploidy, obstructive uropathy, postnatal pyeloplasty and vesicoureteral reflux. Although evidence continues to mount regarding the importance of fetal pyelectasis, little is known of the variability of collecting system measurements. To investigate the short-term variability and its relationship to bladder dilatation, the following study was conducted.

DESIGN

During May and June 1996, 20 mid- and late-trimester patients with varying degrees of fetal pyelectasis were recruited into this study. Each consented to undergo periodic (every 15 min for 2 h) ultrasound measurements of the fetal renal collecting systems and bladder. To account for anatomic and technical variability in measurement, we used both the sum of the transverse and anterior-posterior (AP) measurements of the collecting systems, and AP measurement alone for comparison. The variability of the collecting system measurements was assessed based upon gestational age, magnitude of pyelectasis and fetal bladder size.

RESULTS

We investigated 38 renal units in 20 patients (eight in the second trimester and 12 in the third). The mean(SE) AP diameter of all kidneys was 5.89(2.49) mm (range 15 (2-17) mm), and the sum of transverse and AP renal collecting system diameters was 13.91(5.73) mm (range 26 (4-31) mm). These data were normally distributed. When assessing the variability in individual kidneys over time, we found the mean variation (minimum to maximum) for the sum of the AP and transverse measurement to be 7.61(4.26) mm and for the AP measurement alone to be 3.80(2.49) mm. No relationship was found between variability of dilatation, magnitude of dilatation or fetal bladder size. Cyclic dilatation of the fetal bladder was observed in all cases. The mean time from maximal to minimal dilatation was 20 min (1.34 observations; range 12-30 min).

CONCLUSIONS

We found the size of the fetal renal collecting system to be highly variable over the course of a 2-h period. Seventy per cent of cases (14 of 20) had both normal (< 4 mm) and abnormal values (> or = 4 mm) during the 2-h study period. Significant caution should be used when considering the implications of renal collecting system dilatation based upon a single AP measurement.

A multicenter outcomes analysis of patients with neonatal reflux presenting with prenatal hydronephrosis

PURPOSE

Approximately 10 to 30% of prenatal cases of hydronephrosis result in the postnatal diagnosis of vesicoureteral reflux. Using a new generic prenatal-postnatal data sheet developed by the Society for Fetal Urology the characteristics, natural history and outcome of prenatal hydronephrosis confirmed postnatally to be vesicoureteral reflux were documented at 3 centers.

MATERIALS AND METHODS

We performed a retrospective multicenter review of Society for Fetal Urology data sheets completed for each patient in whom prenatal hydronephrosis was proved to be postnatal vesicoureteral reflux from 1993 to 1998.

RESULTS

In 56 male and 15 female patients with prenatal hydronephrosis a total of 116 refluxing renal units were confirmed postnatally. Of the 116 renal units 112 were hydronephrotic prenatally. During gestation increased hydronephrosis was noted with voiding in 4 cases. Of the 112 hydronephrotic renal units only 26 ureters in 15 patients were seen prenatally. The obstetrician considered the diagnosis of vesicoureteral reflux in only 24% of the cases. Postnatally 116 refluxing renal units were identified. Initial postnatal ultrasound was normal in 25% of the cases. Bilateral reflux was present in 36 male and 9 female patients. In 10 of the 19 uncircumcised patients (53%) urinary tract infection developed despite antibiotic prophylaxis. In 15 of the 74 renal units with grades III to V reflux the condition resolved at an average patient age of 0.9 and 2.1 years in boys and girls, respectively. A total of 27 refluxing renal units were reimplanted.

CONCLUSIONS

The majority of prenatal reflux occurs in boys, and it is high grade and bilateral. The data sheets designed by the Society for Fetal Urology are useful data collection instruments. The presentation and natural history of vesicoureteral reflux are different in male and female individuals. In a significant number of renal units high grade reflux resolves spontaneously. Early circumcision may decrease the incidence of breakthrough urinary tract infection in this subpopulation. In addition, the effective management of prenatally detected reflux depends on multispecialty communication.

A multicenter outcomes analysis of patients with neonatal reflux presenting with prenatal hydronephrosis

PURPOSE

Approximately 10 to 30% of prenatal cases of hydronephrosis result in the postnatal diagnosis of vesicoureteral reflux. Using a new generic prenatal-postnatal data sheet developed by the Society for Fetal Urology the characteristics, natural history and outcome of prenatal hydronephrosis confirmed postnatally to be vesicoureteral reflux were documented at 3 centers.

MATERIALS AND METHODS

We performed a retrospective multicenter review of Society for Fetal Urology data sheets completed for each patient in whom prenatal hydronephrosis was proved to be postnatal vesicoureteral reflux from 1993 to 1998.

RESULTS

In 56 male and 15 female patients with prenatal hydronephrosis a total of 116 refluxing renal units were confirmed postnatally. Of the 116 renal units 112 were hydronephrotic prenatally. During gestation increased hydronephrosis was noted with voiding in 4 cases. Of the 112 hydronephrotic renal units only 26 ureters in 15 patients were seen prenatally. The obstetrician considered the diagnosis of vesicoureteral reflux in only 24% of the cases. Postnatally 116 refluxing renal units were identified. Initial postnatal ultrasound was normal in 25% of the cases. Bilateral reflux was present in 36 male and 9 female patients. In 10 of the 19 uncircumcised patients (53%) urinary tract infection developed despite antibiotic prophylaxis. In 15 of the 74 renal units with grades III to V reflux the condition resolved at an average patient age of 0.9 and 2.1 years in boys and girls, respectively. A total of 27 refluxing renal units were reimplanted.

CONCLUSIONS

The majority of prenatal reflux occurs in boys, and it is high grade and bilateral. The data sheets designed by the Society for Fetal Urology are useful data collection instruments. The presentation and natural history of vesicoureteral reflux are different in male and female individuals. In a significant number of renal units high grade reflux resolves spontaneously. Early circumcision may decrease the incidence of breakthrough urinary tract infection in this subpopulation. In addition, the effective management of prenatally detected reflux depends on multispecialty communication.

Features of primary vesicoureteric reflux detected by investigation of foetal hydronephrosis

Primary vesicoureteric reflux (VUR) diagnosed on investigation of foetal hydronephrosis accounts for many antenatally detected uropathies. In order to study foetal VUR and its consequences, newborns with foetal hydronephrosis were investigated by ultrasound, micturating cystourethrogram and 99mTechnetium-dimercapto-succinic acid (DMSA), after beginning of chemoprophylaxis. Twenty-eight infants with VUR (bilateral in 15 cases) were identified giving a total 43 renal units for study. There was a predominance of males (86%), moderate/severe reflux (84%) and renal damage (51%). Presence of renal damage was correlated with the severity of reflux. VUR should be investigated in cases of foetal hydronephrosis and our results support that renal damage is frequently congenital and not secondary to urinary tract infection.

Early versus late surgical management of fetal reflux nephropathy

PURPOSE

Considering that infants with reflux nephropathy may be susceptible to urinary tract infection or longer postnatal vesicoureteral reflux, an early antireflux procedure rather than chemoprophylaxis may be indicated after birth.

MATERIALS AND METHODS

In 15 male and 7 female neonates bilateral and unilateral primary high grade vesicoureteral reflux was detected prenatally in 15 and 7, respectively, on the basis of dilatation of the urinary tract. There was grade III or IV reflux in the 37 refluxing renal units and all patients received chemoprophylaxis after birth. In 11 neonates congenital reflux nephropathy was diagnosed during month 1 of life, including 5 (9 refluxing renal units) who underwent early antireflux surgery without evidence of urinary tract infection and 6 (11 refluxing renal units) who underwent late surgery with a history of urinary tract infection. All patients treated nonsurgically and surgically were monitored up to 2 years and for 2 years postoperatively, respectively.

RESULTS

Of the 11 patients (17 renal units) without congenital reflux nephropathy reflux improved in 53%, a documented urinary tract infection occurred in 2 and there was no development of new scars in a previously normal kidney. In the 11 patients (20 renal units) with congenital reflux nephropathy the parenchymal defect detected during month 1 of life was general or focal, that is at the mid zone as well as the poles. Surgery was performed at a mean of 8 weeks of life in 5 patients without a documented urinary tract infection, 24 weeks earlier than in the 6 with a history of urinary tract infections. Postoperative breakthrough infections occurred in all 6 infants who underwent late surgery and in none who underwent early surgery (p < 0.05). New scarring developed in previously scarred renal units but there was more new scarring in the renal units treated with late surgery (10 of 11, 90%) than in those treated with early surgery (2 of 9, 22%, p < 0.001). In both groups retardation of growth was identified in the renal units with general nephropathy.

CONCLUSIONS

Renal units with fetal reflux nephropathy were susceptible to urinary tract infections and new scar formation. Early antireflux surgery performed before a urinary tract infection develops offers a better prognosis than late surgery.

Pyelectasis of the newborn

In the course of the ultrasound screening of 7057 newborns, 429 (6.1%) pyelectases were encountered (the pyelon was 5 mm or wider). Up to the termination of the study 91.7% of the newborns with pyelectasis could be controlled. In 341 (86.3%) out of the 395 controlled cases, pyelectasis disappeared without causing any disturbances. In 54 cases (13.7%) pyelectasis increased, or the considerable pyelectasis accompanied by calyectasis was not found to be reduced by the first control examinations. Vesicoureteral reflux was observed in 8 (14.8%) of these cases. Following a long-term observation period, all pyelectases disappeared or diminished considerably. Hydronephrosis was encountered in 23 newborns, 9 of them underwent surgery. The frequency of pyelonephritides was 1.4% during infancy of the newborns with pyelectasis. Pyelectasis of the newborn is considered a benign alteration. Its further examination is indicated if it increases and is accompanied by considerable calyectasis or ureterectasis.

Antenatal diagnosis of urinary tract abnormalities by ultrasonography after 28 weeks' gestation: incidence and outcome

OBJECTIVE

The objective was to establish the likelihood that antenatal upper urinary tract dilatation identified after 28 weeks of gestation will progress to significant postnatal uropathy.

STUDY DESIGN

In 5 years, 3856 fetuses had ultrasonography after 28 weeks of gestation when the mothers were first seen in advanced pregnancy for delivery appointments or for other obstetric indications. Fetuses with urinary tract anomalies had ultrasonographic surveillance after 6 days and 6 weeks of life with further evaluation as necessary.

RESULTS

Renal tract anomalies were identified in 313 fetuses, and 55 infants had significant renal tract abnormalities. There were 7 deaths; 2 infants were anephric and 5 with hydronephrosis had lethal congenital abnormalities. Dilatation of the upper urinary tract was identified in 7.7% of the fetuses (298/3856) but was transient in 216 of them (72%). Follow-up of children with transient renal pelvis dilatation found only one with a history of urinary tract infection. Obstruction occurred in 23 infants (6.0/1000) and 16 required surgical correction. Vesicoureteric reflux was identified in 14 infants (3.6/1000) and resolved by age 2 years in 64%. Unilateral multicystic renal dysplasia occurred in 8 and posterior urethral valves occurred in 3 infants.

CONCLUSION

Antenatal ultrasonography after 28 weeks' gestation identified significant renal tract abnormalities with a frequency of 14.3 per 1000 births, permitting early treatment of the asymptomatic newborn and reducing later renal damage.

Mild fetal hydronephrosis indicating vesicoureteric reflux

The management of neonates with mild hydronephrosis diagnosed antenatally is still debated. Although some of these infants are normal, it is recognised that others will have mild obstruction of the ureteropelvic junction or vesicoureteric reflux (VUR). A prospective study was performed in all newborn infants with an antenatal diagnosis of mild hydronephrosis (47 babies, 62 kidneys) born over a two year period in order to assess the frequency of VUR. Voiding cystography in 14 patients with 21 renal units showed VUR. Two patients underwent surgery and the VUR resolved; the other 12 received medical treatment. Repeat cystography was scheduled for 12-18 months later, when a high rate of spontaneous cure was observed. The remaining patients were monitored by ultrasonography but only in one case did hydronephrosis deteriorate because of the presence of severe ureteropelvic junction obstruction. It is concluded that mild dilatation of the pelvis might be an expression of a potentially severe malformation such as VUR, and a careful follow up of these cases is mandatory.

The small scarred kidney in childhood

Reflux nephropathy is now a generally accepted term to describe small scarred kidneys discovered during childhood; it recognises the close association between this renal lesion and vesicoureteric reflux (VUR). This paper briefly reviews the pathogenic factors involved in reflux nephropathy and suggests that at least two main mechanisms operate: acquired segmental scarring due to intrarenal reflux and congenital maldevelopment (renal dysplasia). The spectrum of renal changes associated with VUR can be usefully divided on this basis and the opportunity to recognise by fetal ultrasound those renal lesions acquired in utero may further enhance our understanding of the congenital maldevelopment group.

Primary vesicoureteral reflux in infants with a dilated fetal urinary tract

Vesicoureteral reflux (VUR) was recognized neonatally by voiding cystography in 25 of 117 infants with a dilated fetal urinary tract. There was a male preponderance (76%) and a high percentage (40%) of associated urinary malformations. Thirty-nine refluxing units were studied. All grades of VUR were detected but gross dilating VUR dominated (59%). Spontaneous resolution was excellent in lower grades of VUR but was poor in gross VUR. Surgery was successfully performed in 13 renal units of nine patients with gross reflux, additional ipsilateral malformations, or pyelonephritis during antibiotic prophylaxis. Segmental renal scars developed in four kidneys after urinary infections, and a diffuse parenchymal lesion was noted in nine kidneys even at birth. One boy with duplication had a non-functioning refluxing system. Our results in a small number of infants show differences to children with VUR detected after urinary infections and seem to support the existence of a congenital reflux nephropathy.

Follow-up evaluation of anomalies of the vesicoureteric junction

Anomalies of the vesicoureteric junction are important, particularly obstruction and reflux, as they may predispose to urinary tract infection. Over a 5-year period, 52 babies were referred with dilatation of the urinary tract detected antenatally or/and postnatally by ultrasound. Sixteen had an anomaly of the vesicoureteric junction: 9 had vesicoureteric reflux, 3 had ureteroceles, 1 had urethral stenosis with secondary reflux and 3 had stenosis of the vesicoureteric junction. Ten patients underwent 14 surgical procedures. The mean time to reconstructive surgery was 9.3 months. Ultrasonography showed regression of the dilatation in all patients who underwent surgery. Seven patients with minor dilatation are still under observation. In only 1 case was there loss of renal parenchyma. With conservative medical treatment the patients are 1 year old before reconstructive surgery is undertaken; with reflux, however, progression may indicate earlier surgery.

Fetal vesicoureteral reflux: outcome following conservative postnatal management

Of 222 infants with a urinary tract abnormality detected antenatally 30 male and 9 female patients (64 renal units) were found to have primary vesicoureteral reflux. Grade of reflux was predominantly severe, with grade III or higher noted in 83% of the patients. Prenatal and postnatal ultrasound failed to detect any abnormality in 29 refluxing units (45%) discovered contralateral to the known abnormal system, although 19 had grade III or higher reflux. Of the 64 refluxing units 8 underwent primary ureteral reimplantation, 12 were lost to followup and 44 were managed conservatively for a mean of 3.3 years. Reflux ceased in 61% of the cases, improved in 14% and remained unchanged in 23%. In only 1 unit did the grade of reflux increase. Documented urinary tract infection occurred in 6 of the 39 reflux patients. Dimercaptosuccinic acid renography performed in 21 infection-free patients demonstrated global reduction in renal parenchyma in 4 units, focal parenchymal defects in 3 and normal function in 14. Conservative postnatal management of fetal vesicoureteral reflux is justified. Global and focal parenchymal changes can occur in the kidneys of infants with reflux despite the absence of urinary tract infection.

Commentary: importance of antenatal diagnosis of vesicoureteral reflux

Although hydronephrosis detected by prenatal ultrasonography often is assumed to be secondary to obstructive uropathy, in approximately 10% of the cases renal pelvic dilatation results from primary vesicoureteral reflux. More than 80% of neonates with reflux are male and two-thirds have bilateral reflux. Approximately 80% have at least grade III reflux. At birth between a third and half may have reduced renal function on isotope renography, even in the absence of urinary infection. Approximately 20% of neonates with grade IV or V reflux followed nonoperatively experience spontaneous reflux resolution by age 2 years. However, in approximately 25% of boys followed nonoperatively urinary tract infections developed by age 2 years despite antimicrobial prophylaxis. Because the majority of these boys have been uncircumcised, circumcision seems advisable. Ureteral reimplantation should be reserved for those with breakthrough urinary tract infection, new renal scars or persistent high grade reflux.

A hypothesis for the higher incidence of vesico-ureteral reflux and primary megaureters in male babies

The authors propose a new explanation for the male preponderance in cases with prenatally diagnosed vesico-ureteral reflux and primary megaureters. The theory is based on conclusions drawn from the characteristics of 4 patients (3 perinatal cases and 1 occurring in a 14-year-old boy) presenting with unusual anomalies of the lower urinary tract. In this hypothesis, the male preponderance could be related to an abnormal dilatation of the posterior urethra occurring during the embryological development of the male urethra. The dilatation leads to a flap valve mechanism and to a functional obstruction of the bladder outlet and finally to secondary dilatation of the upper urinary tract. This obstruction may be transitory; reflux and megaureters found in utero or after birth could be considered as sequellae of this phenomenon.

Vesicoureteric reflux and renal injury

Renal injury associated with the intrarenal reflux (IRR) of urine that is either infected, under high pressure, or both, is a major cause of severe hypertension during childhood and adolescence and of chronic renal insufficiency in patients less than 30 years of age. Many, but not all, adolescent and adult patients with reflux nephropathy (RN) give a history of urinary tract infection (UTI) or unexplained fevers in infancy or early childhood, when the kidney is thought to be at greatest risk of injury. Although vesicoureteric reflux (VUR) is observed more commonly in infants than children with UTI, it is rare in uninfected patients at any age and should never be considered a normal finding during human development. Renal scarring may not be obvious in radiographic or radionuclear studies to medical management alone, no definite benefit of one over the other was observed, regardless of the grade of VUR. Moreover, progressive renal injury in scarred kidneys has been noted even after VUR had been corrected, when infection had been prevented, and while hypertension had been controlled satisfactorily. Focal glomerular sclerosis, a lesion found in patients with proteinuria and RN, has been identified not only in scarred kidneys, but also may be seen in contralateral, unscarred kidneys without VUR, which might suggest a humoral factor or, perhaps, a hyperfiltration phenomenon. RN is one of the most frequent causes of end-stage renal disease (ESRD) in children, adolescents, and young adults, which is potentially preventable. However, prevention will depend on early identification of patients at risk--infants and young children after the first UTI and siblings of patients with VUR--aggressive and effective treatment of UTI, minimizing intravesical pressure, and education of patients, parents, and physicians.

Relation of urinary tract infection and vesicoureteral reflux to scars: follow-up of thirty-eight patients

A prospective study compared the outcome of vesicoureteral reflux and recurrent urinary tract infections in children (3 boys, 62 girls) who received medical prophylaxis or underwent surgical correction of reflux. Thirty-eight children returned for reevaluation 6 to 13 years (average 9.5 years) after entry. There was a marked decrease in prevalence and severity of reflux. At entry, 13 had significant scarring that had progressed at follow-up. New scars were documented by dimercaptosuccinic acid scan at follow-up in eight children on the medical regimen and two who were initially treated with surgical correction of reflux. Four patients with high-grade sterile reflux were followed for 6 to 10 years without the development of cortical scars. Our data support the role of urinary tract infection and vesicoureteral reflux, but not sterile reflux, in the pathogenesis of chronic pyelonephritis and reflux nephropathy.