Vesicoureteral reflux in boys

Technical report: urinary tract infections in febrile infants and young children. The Urinary Tract Subcommittee of the American Academy of Pediatrics Committee on Quality Improvement

OVERVIEW

The Urinary Tract Subcommittee of the American Academy of Pediatrics Committee on Quality Improvement has analyzed alternative strategies for the diagnosis and management of urinary tract infection (UTI) in children. The target population is limited to children between 2 months and 2 years of age who are examined because of fever without an obvious cause. Diagnosis and management of UTI in this group are especially challenging for these three reasons: 1) the manifestation of UTI tends to be nonspecific, and cases may be missed easily; 2) clean voided midstream urine specimens rarely can be obtained, leaving only urine collection methods that are invasive (transurethral catheterization or bladder tap) or result in nonspecific test results (bag urine); and 3) a substantial number of infants with UTI also may have structural or functional abnormalities of the urinary tract that put them at risk for ongoing renal damage, hypertension, and end-stage renal disease (ESRD).

METHODS

To examine alternative management strategies for UTI in infants, a conceptual model of the steps in diagnosis and management of UTI was developed. The model was expanded into a decision tree. Probabilities for branch points in the decision tree were obtained by review of the literature on childhood UTI. Data were extracted on standardized forms. Cost data were obtained by literature review and from hospital billing data. The data were collated into evidence tables. Analysis of the decision tree was used to produce risk tables and incremental cost-effectiveness ratios for alternative strategies.

RESULTS

Based on the results of this analysis and, when necessary, consensus opinion, the Committee developed recommendations for the management of UTI in this population. This document provides the evidence the Subcommittee used in the development of its recommendations.

CONCLUSIONS

The Subcommittee agreed that the objective of the practice parameter would be to minimize the risk of chronic renal damage within reasonable economic constraints. Steps involved in achieving these objectives are: 1) identifying UTI; 2) short-term treatment of UTI; and 3) evaluation for urinary tract abnormalities.

Congenital reflux nephropathy: a follow-up of 108 cases diagnosed perinatally

OBJECTIVE

To determine: (i) the proportion of vesicoureteric reflux (VUR) associated with congenital renal damage and whether it can be severe enough to cause renal impairment from birth: (ii) to evaluate the distribution of males and females affected; and (iii) to describe the course of congenital damage in the first years of life.

PATIENTS AND METHODS

A total of 108 children (76 male and 32 female, M:F 2.3:1), whose VUR was diagnosed before any infection, were followed from birth for a mean (range) of 4.3 (1-10) years. Renal damage was defined by serum creatinine concentration, creatinine clearance and renal imaging (ultrasonography and renal scintigraphy) performed within the first month of life and periodically thereafter.

RESULTS

Of the 108 children, 58 had bilateral and 50 unilateral reflux (total number of refluxing units, 166). High-grade VUR (grade > or = 4) was found in 96 (58%) refluxing renal units (RRUs). Males had a prevalence of bilateral severe (> or = grade 4) reflux (M:F 5.2:1), while in those wit unilateral VUR, the M:F ration was 1.5:1. At birth, mild to moderate damage was present in 56 (36%) RRUs and only associated with VUR of grade > or = 3. Bilateral reflux of grade > or = 4 was associated with congenital moderate/severe renal failure in nine neonates (seven males). In infants with grade > or = 4 VUR who underwent surgical correction, VUR resolved in 92% of cases. In infants with VUR of grade > or = 4 followed medically, the reflux spontaneously resolved in 42% and ameliorated in 16% after 18 months. Serial renal scans during the follow-up showed no progression of renal damage.

CONCLUSIONS

VUR diagnosed at birth on prenatal ultrasonography is associated with congenital damage, with males affected more often than females. The damage involves both kidneys in a consistent proportion and is an important cause of chronic renal impairment from birth. It does not progress in the first years of life if infections are prevented. It is suggested that males with this condition may constitute a major group at risk of developing chronic renal failure in later life.

Rational use of CT in acute pyelonephritis: findings and relationships with reflux

Enhanced renal CT scanners were performed in 38 children (82% girls) to rule out acute pyelonephritis. Patients were divided in 2 groups on the basis of clinical presentation and bacteriology data. In patients of group A (n = 16, preliminary study), upper urinary tract infection (UTI) was certain. CT confirmed the diagnosis in all but 3 patients (a 2-year-old child and 2 patients with UTI developed on prior obstruction). In subsequently studied patients of group B (n = 22), clinical findings or bacteriology data were negative or questionable. CT made the diagnosis of acute pyelonephritis in 11 patients. As well as DMSA scintigraphy, CT scanner can help to diagnose or to rule out upper UTIs in difficult cases. In all boys of both groups, ipsilateral vesico-ureteric reflux (VUR) was found by subsequent voiding cystourethrography (VCUG) on the side of pyelonephritis. In girls, this correlation was shown in only 7 of the 25 kidneys with pyelonephritis. This result supports the hypothesis of a gender-dependent contamination. We believe that absence of radiologic reflux cannot exclude the possibility of bacterial crossings of ureteric meatus capable to lead to genuine upper UTIs.

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.

Followup of conservatively treated children with high and low grade vesicoureteral reflux: a prospective study

A total of 202 children (mean age 31.5 +/- 23.3 months) with vesicoureteral reflux identified during the investigation that follows a urinary tract infection entered this prospective study dealing with the medical management of reflux. The diagnosis of vesicoureteral reflux was made significantly earlier in boys than in girls regardless of reflux grade (p < 0.001). At entry reflux nephropathy was present on a dimercaptosuccinic acid scan in 44% of 314 refluxing kidneys. There was no significant difference between boys and girls in the prevalence of reflux nephropathy. The renal lesions were more severe in boys independently of the grade of vesicoureteral reflux (p < 0.05). Breakthrough urinary tract infection was significantly more common in girls than in boys, regardless of vesicoureteral reflux grade (p < 0.05). Mean followup was 68.7 +/- 31.2 months. Patient age at the time of the first of 2 radionuclide cystograms without vesicoureteral reflux was considered the age of spontaneous resolution of reflux. Using life table estimations and analyzing data stratified to sex and grade of vesicoureteral reflux, we found that although reflux lasted longer in boys compared to girls, this difference was not statistically significant. During followup new scars developed in 7 patients related to breakthrough urinary tract infection. There was no significant difference between boys and girls in the development of new scars. To understand the natural history of vesicoureteral reflux children must be stratified by sex and grade of reflux.