The relationship of sibling reflux to index patient dysfunctional voiding

Incidence of Urinary Tract Infection Among Siblings of Children With Vesicoureteral Reflux

BACKGROUND

Siblings of children with vesicoureteral reflux (VUR) are at elevated risk of VUR. Screening siblings may identify VUR before a clinical illness such as a urinary tract infection (UTI), but the benefit of screening has not been demonstrated. We sought to determine the incidence of UTI among siblings, and we hypothesized that the sibling UTI rate is similar between screened and unscreened siblings.

METHODS

We performed a retrospective cohort analysis using insurance claims data (January 1, 2000, to December 31, 2009). Within each family, we identified the index VUR patient and siblings; we included siblings who were enrolled in the insurance plan from birth for at least 1 year. We identified siblings who were screened for VUR and/or had UTI. We investigated the association of screening and UTI, controlling for patient characteristics and clustering within families.

RESULTS

Among 617 siblings (associated with 497 index patients), 317 (51%) were girls. Median insurance enrollment time was 53.0 months, with 424 enrolled ≥3 years. Among those with 1 or 3 years of enrollment, the proportions of siblings who experienced UTI was 8.4% (52 of 617) and 10.4% (44 of 424), respectively. Median age at initial UTI was 32.7 months. A total of 223 siblings (36.0%) underwent sibling screening. There was no significant difference in UTI between screened and unscreened siblings (odds ratio 1.57, 95% confidence interval 0.87-2.85; P = .14). In multivariate analysis, screening was not associated with sibling UTI incidence (odds ratio 1.33, 95% confidence interval 0.68-2.60; P = .40).

CONCLUSIONS

Although UTI is relatively common among siblings of VUR patients, there was no statistically significant difference in UTI incidence between screened and unscreened siblings.

Vesicoureteric reflux deterioration in monozygotic twins

Primary vesicoureteric reflux (VUR) is the most common inherited structural urinary tract disorder, conforming closely to autosomal dominant transmission. A pair of monozygotic siblings is described exhibiting a remarkably parallel clinical course. VUR grade II was diagnosed in girl A during urinary tract infection at the age of 2 yr; screening of her asymptomatic sister (girl B) revealed the same. Renal cortical scintigraphy unveiled unilateral hypo-dysplasia in both the twins. Despite trimethoprime-sulfamethoxazole prophylaxis, infection recurred in girl A after 7 months, while girl B had a first episode 2 months later that prompted regimen switch to nitrofurantoin. Follow-up at the age of 4 depicted bilateral reflux deterioration; an urodynamics study that followed revealed functional bladder instability in both girls and the oral antispasmodic oxybutynin was initiated with good results. Evaluation for reflux should be prompt in infants with urinary infection. Patient siblings display a higher relative reflux risk, being highest in identical twins. Heredity issues, the impact of age and dysfunctional voiding in the clinical course, and the contribution of nuclear medicine in VUR management are discussed.

Screening for vesicoureteral reflux and renal scars in siblings of children with known reflux

The incidence of vesicoureteral reflux (VUR) in the general population is less than 1%, but it is high in families with reflux. The reported prevalence of VUR among siblings of index patients with reflux has ranged from 4.7% to 51%. Reflux carries an increased risk of pyelonephritis and long-term renal impairment. The purpose of this study was to identify the age-related incidence and severity of reflux, and the frequency of associated renal parenchymal damage in siblings of children with reflux in order to assess the use of screening at different ages. Between October 1994 and February 2003, 40 siblings of 34 index patients were screened with direct voiding cystography. 99( m ) technetium (Tc)-dimercaptosuccinic acid (DMSA) nuclear renal scans were performed in siblings with VUR to detect renal scarring. The cystograms were interpreted as showing the presence or absence of VUR and the DMSA scan as symmetrical or asymmetrical differential function, with or without renal scarring. Of 40 siblings, 17 had VUR, representing an incidence of 42.5%. The mean age at study entry of the 15 boys and 25 girls was 63 months (range 6 months to 12 years). The majority of siblings with abnormal DMSA scans were asymptomatic. Reflux was unilateral in 12 siblings and bilateral in 5. Of the 17 refluxing siblings (22 refluxing ureters), 7 (41.17%) had a history of symptomatic urinary tract infection (UTI). The frequency of VUR was nearly equal in siblings over 6 years and those younger than 6 years. Of the 17 siblings with VUR, 16 had DMSA scintigraphy. Of these, 5 were normal and 11 (68.75%) showed abnormalities (7 asymmetrical differential function and 4 parenchymal defect), which was bilateral in 7 and unilateral in 4. In conclusion, this study confirms a significant overall incidence of VUR and renal parenchymal damage in the siblings of patients with known reflux. The prevalence of reflux in older siblings is similar to that in younger siblings. Our review suggests that all siblings over 6 years should undergo a screening cystogram, even in the absence of urinary tract infection. DMSA scintigraphy of asymptomatic siblings appears to be beneficial in preventing renal injury.

Screening siblings for vesicoureteral reflux

PURPOSE

Publications on screening the siblings of patients with reflux were reviewed to determine the overall incidence and severity of reflux and renal scarring in siblings, and identify factors that predict siblings more likely to have reflux.

MATERIALS AND METHODS

A MEDLINE search for 1985 to the present was performed. Of 34 articles on familial reflux only 11, including 1 abstract, on sibling screening were used in this analysis.

RESULTS

The mean incidence of reflux in siblings in all studies was 32% (570 of 1,768). Of the siblings with reflux approximately two-thirds had grades I to II disease. Only 22 of 1,051 siblings (2%) had reflux greater than grade III. Reflux was unilateral in 162 of 307 cases (53%). Certain factors predicted the chance of sibling reflux. Sibling age varied inversely with the incidence of reflux. A twin relationship and absent dysfunctional voiding symptoms in the index patient may predict a higher chance of reflux in a sibling. The mean incidence of renal abnormality in siblings with reflux was 11%. The incidence of reflux and renal abnormality in the sibling population undergoing screening was 3%. In more than half of the siblings with an abnormal renal evaluation there was no history of urinary tract infection.

CONCLUSIONS

The studies reveal an incidence of reflux in siblings greater than in the general population. These data do not prove that screening and treating asymptomatic siblings decreases infectious renal scarring. Studies in a control group that consider sibling age are still needed to determine the benefit of screening asymptomatic siblings.

Sibling vesicoureteral reflux in multiple gestation births

BACKGROUND

Vesicoureteral reflux (VUR) is the most commonly inherited disease of the genitourinary tract. Although the majority of evidence supports a genetic cause, the tendency for this condition to spontaneously improve over time has made it difficult to determine the actual mode of transmission. We report the incidence of VUR in siblings of multiple gestation births and for the first time compare the relative incidence of reflux between identical and fraternal twins.

METHODS

A database consisting of all radionuclide cystograms and voiding cystourethrograms performed between the years 1986 and 1996 was searched for multiple gestation births. The medical records of each patient were evaluated for age at presentation, zygosity, reflux grade, and time to resolution. Children with secondary causes of VUR (eg, posterior urethral valves) were excluded. Triplets were treated as 2 pairs of twins for statistical analysis.

RESULTS

Forty-six pairs met the inclusion criteria (31 dizygotic and 15 monozygotic). Overall, 23 (50%) of 46 siblings of index cases had demonstrable VUR. Comparison of VUR prevalence between identical and nonidentical twins was revealing with 80% (12/15) of identical twins and 35% (11/31) of fraternal twins having VUR. When only the youngest individuals in each group were considered, 100% (7/7) of the monozygotics and 50% (5/10) of the dizygotics demonstrated this trait.

CONCLUSIONS

High concordance for VUR in identical twin siblings supports a genetic basis for the transmission of this disease. Results obtained from fraternal twin siblings provides convincing evidence that this trait is transmitted in an autosomal dominant fashion.

Vesicoureteral reflux in male and female neonates as detected by voiding ultrasonography

BACKGROUND

Vesicoureteral reflux (VUR) is assumed to be congenital, and its early diagnosis is desired in order to prevent acquired renal damage. However, the incidence of VUR in neonates remains to be revealed.

METHODS

Two thousand newborn babies (1048 boys and 952 girls) underwent voiding ultrasonography (an ultrasound examination of urinary tract during provoked voiding). Those who showed transient renal pelvic dilation during voiding, who had small kidneys, or who subsequently developed urinary infection underwent voiding cystourethrography.

RESULTS

Transient renal pelvic dilation was observed in 16 babies (0.8%), including one boy with small kidneys. Among the rest of the babies, one boy had a small kidney, and nine babies subsequently developed urinary infection. Voiding cystourethrography revealed VUR in 24 ureters of 16 children (11 boys and 5 girls). Dimercaptosuccinate renoscintigraphy confirmed small kidneys, with generally reduced tracer uptake in a total of three boys, all having VUR. Voiding ultrasonography detected transient renal pelvic dilation in 17 (71%) of the 24 kidneys with VUR and, strikingly, 16 of the 17 (94%) kidneys with high-grade VUR (grade III or more).

CONCLUSION

This study effectively detected VUR in 0.8% of the neonates (mostly of high grades and predominantly in males) and voiding ultrasonography showed a decided usefulness for the detection of VUR. The male preponderance of VUR in neonates was considered to be due to the occurrence of congenitally small kidneys, with reflux found exclusively in males and easier ultrasound detection of VUR in male neonates because the majority of diagnoses are reported to be high grades of VUR.

Dysfunctional voiding syndromes and vesicoureteral reflux

Micturition disorders simulating neurogenic bladder disease have been loosely termed "dysfunctional voiding". No underlying neuropathy can be found. A variety of voiding disturbances have been identified since the early 1970s, each with its own characteristics and clinical relevance. We have classified voiding dysfunctions into mild, moderate and severe, according to their potential impact on the upper tracts. Bladder instability, the Hinman syndrome and the Ochoa syndrome are the only dysfunctional voiding syndromes that are associated with reflux or ureterovesical obstruction. Each syndrome is briefly described.

Vesicoureteric reflux and renal scars in asymptomatic siblings of children with reflux

The purpose of the study was to determine the incidence of vesicoureteric reflux (VUR), renal scars and hypertension in asymptomatic siblings of children with VUR. The study comprised 105 siblings of patients with VUR. Their age ranged from 4 months to 6.3 years. All had a direct radionuclide voiding cystography (DRVC) performed, and VUR was detected in 47 of 105 (45%). High grade VUR in the first year of life had an incidence of 50% compared with a 9% incidence in siblings older than 2 years, while only one of the 27 siblings with a low VUR grade was younger than 1 year. In 43 of 47 siblings with VUR, a technetium-99m dimercaptosuccinic acid (99mTc-DMSA) scan was performed and renal scars were found in 10, which presents 23% of siblings with VUR who were scanned and 10% of all siblings studied. One child had hypertension. Identifying VUR among asymptomatic siblings could possibly prevent renal damage and its consequences. Thus, the predictive value of positive family history alone in identifying VUR was 45% while 23% of siblings had renal scars. This incidence justifies the routine investigation of asymptomatic siblings, by using DRVC at an early stage.

Familial reflux: vesicoureteral reflux in all siblings of a family

A family is presented in which 4 of 4 (100%) siblings demonstrate vesicoureteral reflux on voiding cystogram. Mechanisms of inheritance are reviewed.

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.