Associated urological anomalies in children with unilateral renal agenesis

Retrospective evaluation of children with unilateral renal agenesis

BACKGROUND

Children born with unilateral renal agenesis (URA) are thought to have a risk of developing hypertension, proteinuria, and progressive chronic kidney disease (CKD). The present study aimed to evaluate the long-term prognosis and clinical characteristics of children with URA.

METHODS

The study included 171 patients aged < 18 years diagnosed as URA who were followed-up for ≥ 1 year and 121 healthy controls matched for age, gender, and BMI.

RESULTS

Median age at diagnosis was 2 years (IQR: 1 month-16 years) and the incidence of URA in males (65.4%) was higher than in females. Among the patients, 21 (12.2%) had other urinary system anomalies. It was noted that 2.3% of the patients had proteinuria, 15.2% had hyperfiltration, and 2.9% had CKD. Hypertension based on ambulatory blood pressure monitoring (ABPM) was diagnosed in 18 (10.5%) of the patients, of whom 10 had masked hypertension. Diastolic blood pressure in the URA patients was significantly higher than in the healthy controls. The incidence of hypertension and CKD was significantly higher in the patients with other urinary system anomalies.

CONCLUSIONS

Patients with a single functional kidney should be periodically evaluated throughout their lifetime for urine protein, blood pressure, and kidney functions. The most remarkable finding of this study is the importance of the use of ABPM for evaluating blood pressure in pediatric URA patients, especially for the detection of masked hypertension and the non-dipper phenomenon, which cannot be achieved with office blood pressure measurement.

Kongenitale Anomalien der Nieren und ableitenden Harnwege (CA KUT)

Der Begriff CAKUT (Congenital Anomalies of the Kidney and Urinary Tract) bezeichnet diverse angeborene Fehlbildungen der Nieren und ableitenden Harnwege. Da alle CAKUT-Phänotypen zusammengenommen etwa 15–30 % aller pränatal diagnostizierten Fehlbildungen ausmachen und etwa 40 % der Fälle mit terminalem Nierenversagen bei Kindern und Jugendlichen verursachen, sind diese Anomalien epidemiologisch hochrelevant. Die Diagnosestellung erfolgt mit radiologischen Verfahren, insbesondere mit Ultraschall, wobei bei vielen Patienten eine Kombination verschiedener CAKUT-Phänotypen nachgewiesen wird. CAKUT tritt zu etwa 85 % sporadisch auf, zu etwa 15 % familiär. Das Vererbungsmuster ist häufig dominant, kann aber auch rezessiv sein. CAKUT kann isoliert auftreten, aber auch als Teil einer syndromalen Erkrankung. Variable Expressivität und inkomplette Penetranz sind bei CAKUT häufig. CAKUT ist genetisch sehr heterogen. Im Mausmodell wurden bislang über 180 CAKUT-assoziierte Gene beschrieben. Da Mutationen in den etwa 50 bisher bekannten humanen CAKUT-Genen nur ca. 20 % der CAKUT-Fälle erklären und sich verschiedene chromosomale Aberrationen wie Mikrodeletionen in weiteren ca. 15 % der Patienten insbesondere mit syndromalen CAKUT finden, sind exom-/genomweite Screeningverfahren für die Aufklärung genetischer CAKUT-Ursachen besonders geeignet. Bei sporadischen Fällen ist eine Trio-basierte Analyse der Exome/Genome von Patienten-Eltern-Trios zur Identifizierung von De-novo-Aberrationen und biallelischen Varianten vielversprechend. Eine Abklärung der genetischen Ursache ist für die Präzisierung von Wiederholungsrisiken sowie eine gezielte Untersuchung von CAKUT-Patienten im Hinblick auf extrarenale Phänotypen von klinischer Bedeutung.

Microarray analysis in pregnancies with isolated unilateral kidney agenesis

BackgroundThe objective of our study was to examine the risk for submicroscopic chromosomal aberrations among fetuses with apparently isolated solitary kidney.MethodsData acquisition was performed retrospectively by searching Israeli Ministry of Health-computerized database. All cases having chromosomal microarray analysis (CMA), referred because of an indication of isolated unilateral kidney agenesis between January 2013 and September 2016, were included. Rate of clinically significant CMA findings in these pregnancies was compared to pregnancies with normal ultrasound, based on a systematic review encompassing 9,792 cases and local data of 5,541 pregnancies undergoing CMA because of maternal request.ResultsOf the 81 pregnancies with isolated solitary kidney, 2 (2.47%) loss-of-copy number variants compatible with well-described deletion syndromes were reported (16p11.2-16p12.2 and 22q11.21 microdeletion syndromes). In addition, one variant of unknown significance was demonstrated. The relative risk for pathogenic CMA findings among pregnancies with isolated unilateral renal agenesis was not significantly different compared with the control population.ConclusionCMA analysis in pregnancies with unilateral renal agenesis might still be useful, to the same degree as it can be in the general population.

Screening for Mullerian anomalies in patients with unilateral renal agenesis: Leveraging early detection to prevent complications

BACKGROUND

Mullerian anomalies have a known association with renal agenesis yet, to date, there are no formal recommendations for screening women with certain renal anomalies for associated genital tract disorders.

OBJECTIVE

The objective of this study is to review current data regarding the association between renal and Mullerian anomalies, and propose screening recommendations.

STUDY DESIGN

A comprehensive review of the literature was performed to identify relevant articles using the keywords "unilateral renal agenesis," "renal anomalies," and "Mullerian anomalies."

RESULTS

Over 30% of patients with unilateral renal agenesis have an associated Mullerian anomaly. However, diagnosis is frequently delayed in this population until after menarche when complications of retrograde menstruation with obstructive anomalies lead to significant problems including endometriosis, pelvic inflammatory disease, and infertility. No clear guidelines exist for communication among the antenatal sonographer, the obstetrician, the parents, and the child's pediatrician, which creates a barrier to effective screening and follow-up. Further, no current guidelines exist for screening women with certain renal anomalies for Mullerian anomalies.

DISCUSSION

The complications of Mullerian anomalies are easily preventable if identified early. We propose new guidelines for education and screening for Mullerian anomalies in patients with unilateral renal agenesis (URA) and multicystic dysplastic kidney (MCDK) to guide providers, patients, and parents on proper identification and management (Table).

CONCLUSIONS

Screening young women with URA and MCDK for Mullerian anomalies has the potential to prevent long-term complications from untreated obstructive malformations. Identification of unilateral renal agenesis on antenatal ultrasound must be clearly articulated with parents and the child's pediatrician so that proper screening can be performed before menarche. Pelvic sonography is a low-cost, high-yield screening tool to identify these anomalies.

Congenital unilateral renal agenesis: Prevalence, prenatal diagnosis, associated anomalies. Data from two birth-defect registries

BACKGROUND

The different mechanisms leading to a solitary kidney should be differentiated because the long-term outcome might be different. The fetal period is the best moment to make a true diagnosis of congenital unilateral renal agenesis (URA). The objective was to determine the prevalence of URA at birth. The secondary objectives were to describe the evolution of sensitivity of prenatal diagnosis over time and the different forms of URA (isolated and associated with other malformations) detected up to 1 year.

METHODS

The cases were retrospectively identified through two French population-based birth defect registries (Auvergne and Bas-Rhin) between 1995 and 2013. Stillbirths and fetuses up to 22 weeks of gestation and infants up to 1 year old with URA were included.

RESULTS

A total of 177 cases of URA were registered. The prevalence at birth was 4.0/10,000. The overall prenatal prevalence was 3.6/10,000 (isolated URA: 2.8/10,000). URA were isolated (59.9%), associated with isolated contralateral congenital anomaly of kidney or urinary tract (CAKUT) (7.3%) and with other extra-renal anomalies (32.8%). The total proportion of contralateral CAKUT was 15%. Only three cases presented an aneuploidy, prenatally detected and conducting to a termination of pregnancy. The sensitivity of prenatal diagnosis improved over time (from 54.2% in 1995 to 1997 to 95.8% in 2010 to 2013; p = 0.002).

CONCLUSION

Our study provides estimates of prevalence of URA at birth. A longitudinal cohort from the antenatal period to puberty should be performed to determine the prognosis of the contralateral kidney among these children with isolated, associated with contralateral CAKUT and URA with extra-renal anomalies. Birth Defects Research 109:1204-1211, 2017. © 2017 Wiley Periodicals, Inc.

Multi-modality imaging review of congenital abnormalities of kidney and upper urinary tract

Congenital abnormalities of the kidney and urinary tract (CAKUT) include a wide range of abnormalities ranging from asymptomatic ectopic kidneys to life threatening renal agenesis (bilateral). Many of them are detected in the antenatal or immediate postnatal with a significant proportion identified in the adult population with varying degree of severity. CAKUT can be classified on embryological basis in to abnormalities in the renal parenchymal development, aberrant embryonic migration and abnormalities of the collecting system. Renal parenchymal abnormalities include multi cystic dysplastic kidneys, renal hypoplasia, number (agenesis or supernumerary), shape and cystic renal diseases. Aberrant embryonic migration encompasses abnormal location and fusion anomalies. Collecting system abnormalities include duplex kidneys and Pelvi ureteric junction obstruction. Ultrasonography (US) is typically the first imaging performed as it is easily available, non-invasive and radiation free used both antenatally and postnatally. Computed tomography (CT) and magnetic resonance imaging (MRI) are useful to confirm the ultrasound detected abnormality, detection of complex malformations, demonstration of collecting system and vascular anatomy and more importantly for early detection of complications like renal calculi, infection and malignancies. As CAKUT are one of the leading causes of end stage renal disease, it is important for the radiologists to be familiar with the varying imaging appearances of CAKUT on US, CT and MRI, thereby helping in prompt diagnosis and optimal management.

Seminoma Arising from Intra-abdominal Cryptorchidism with Ipsilateral Renal Agenesis: A Rare Association

Unilateral renal agenesis is usually asymptomatic and may be found incidentally during examination for other causes. The incidence of testicular tumors arising from cryptorchidism is well established, but if it is coexistent with ipsilateral renal agenesis, the diagnosis and management becomes a challenge. Only three cases of such association have been reported in literature so far. This association has to be kept in mind when dealing with a case of testicular tumor arising from abdominal cryptorchidism, so that the function of the other kidney can be assessed before surgery, and protection given to it in the event of using radiotherapy in an adjuvant setting.

Unilateral renal agenesis: a systematic review on associated anomalies and renal injury

BACKGROUND

Unilateral renal agenesis (URA) is associated with other congenital anomalies of the kidney and urinary tract (CAKUT) and extra-renal anomalies. However, the reported prevalences of these anomalies are highly variable. We estimated the prevalence of associated CAKUT and extra-renal anomalies in patients with URA. Furthermore, we determined the prevalence of renal injury in URA patients.

METHODS

We conducted a systematic review of English and non-English articles using PubMed and Embase.com. Included studies reported at least one of the following items: incidence of URA, gender, side of URA, prenatal diagnosis, performance of micturating cystourethrogram, associated CAKUT, urinary tract infection or extra-renal anomalies. Studies that described a mean/median glomerular filtration rate (GFR) and proportions of patients with hypertension, micro-albuminuria or a decreased GFR were also included.

RESULTS

Analyses were based on 43 included studies (total number of patients: 2684, 63% male). The general incidence of URA was 1 in ∼2000. Associated CAKUT were identified in 32% of patients, of which vesicoureteral reflux was most frequently identified (24% of patients). Extra-renal anomalies were found in 31% of patients. Hypertension could be identified in 16% of patients, whereas 21% of patients had micro-albuminuria. Ten per cent of patients had a GFR<60 mL/min/1.73 m2;.

CONCLUSIONS

These aggregate results provide insight in the prevalence of associated anomalies and renal injury in patients with URA. Our systematic review implicates that URA is not a harmless malformation by definition. Therefore, we emphasize the need for clinical follow-up in URA patients starting at birth.

Congenital anomalies of kidney and hand: a review

‘Acro-renal syndrome’ refers to co-occurrence of congenital renal and limb anomalies. The term acro-renal syndrome was coined by Curran et al. in 1972 though Dieker and Opitz were the first to report this phenomenon in three male patients in 1969. The common limb defects include oligodactyly, ectrodactyly, syndactyly or brachydactyly anomalies of the carpal and tarsal bones and the common renal anomalies observed are unilateral renal agenesis (URA), bilateral renal hypoplasia, ureteric hypoplasia, hydroureteronephrosis and duplication abnormalities. The acro-renal syndrome as originally described is rare, reported only in ∼20 patients in the international literature. We report a 23-year-old male patient with renal anomalies in the form of absent right kidney, left-sided vesicoureteric reflux (VUR) and skeletal anomalies viz short radius, absent first metacarpal ray in left hand and left undescended testis, consistent with Dieker's type acro-renal syndrome. Apart from the classical acro-renal syndrome, several anomalies of acro-renal patterns and the abnormal gene loci involved are described in the literature. This article is a comprehensive review of the development of kidneys, types of acro-renal syndromes, congenital anomalies of the kidney and urinary tract (CAKUT), syndromes associated with combined limb and renal anomalies, and anomalies associated with URA.

Renal functional reserve in children with apparently normal congenital solitary functioning kidney

OBJECTIVE

The aim of the study was to investigate renal functional reserve (RFR) and to assess its relationship with serum cystatin C and blood pressure in children with apparently normal congenital solitary functioning kidney (SFK).

MATERIAL AND METHODS

RFR was obtained from the difference of endogenous creatinine clearance (CrCs) before and after a meat-free oral protein load (OPL) in the patients who were pre-treated with cimetidine. Serum cystatin C and urinary protein excretion were determined before and after OPL.

RESULTS

Among 22 patients (13 boys), aged 9.5 ± 4.3 years, 72.7% had increased serum cystatin C, and 54.5% had decreased RFR. Following OPL, CrCs and urine creatinine increased, while serum creatinine and cystatin C remained unchanged. The multiple regression analysis demonstrated that cystatin C could predict more than 90% of RFR variability.

CONCLUSION

Half of the patients with apparently normal SFK had decreased RFR. Serum cystatin C is one of the best predictors of RFR.

Abdominopelvic ultrasound: a cost-effective way to diagnose solitary kidney

PURPOSE

Solitary kidneys are detected on approximately 1 of 1,500 prenatal ultrasounds and during evaluation for other urological complaints. Although renal scintigraphy is currently the gold standard for confirming the diagnosis and ruling out renal ectopia, scintigraphy is associated with radiation exposure, placement of an intravenous line and sedation. We hypothesize that ultrasonography alone is sufficient to detect solitary kidneys and that confirmatory renal scintigraphy is unnecessary.

MATERIALS AND METHODS

We reviewed the records of children with a solitary kidney who underwent ultrasound and nuclear scintigraphy at our institution from 2001 to 2010. Radiological findings were compared to assess the accuracy of ultrasound in diagnosing solitary kidneys. Costs were calculated based on 2011 Medicare global reimbursement.

RESULTS

A total of 25 children met the inclusion criteria of undergoing ultrasound and renal scintigraphy (dimercapto-succinic acid or mercaptoacetyltriglycine scan). The majority of cases were male (16, 64%) and left sided (17, 68%). Median age was 9 days (range 1 day to 11.6 years) at first ultrasound and 4.4 months (3 weeks to 12 years) at first renal scintigraphy. In 24 patients ultrasound correctly diagnosed a solitary kidney as confirmed by nuclear scan. In 1 patient ultrasound suggested a pelvic kidney but repeat ultrasound was negative, as was dimercapto-succinic acid scan. The diagnostic accuracy of ultrasound was 96%. Medicare reimbursement for dimercapto-succinic acid scan (CPT 78700) is $460 to $720 ($222 plus $240 for radiotracer plus $260 for anesthesia, if used).

CONCLUSIONS

Our findings suggest that ultrasonography alone is sufficient to make the diagnosis of solitary kidney. Omitting routine renal scintigraphy saves approximately $460 to $720 per case, and avoids radiation and discomfort without sacrificing diagnostic accuracy.

Urinary tract anomalies associated with high grade primary vesicoureteral reflux

BACKGROUND

Few studies have evaluated the significance of associated urological anomalies in vesicoureteral reflux (VUR). The aim of our study was to determine the incidence of associated urological anomalies in patients with high grade VUR and to assess their impact on renal parenchymal scarring.

METHODS

We retrospectively reviewed the hospital records of 1,765 consecutive cases diagnosed with high grade VUR (Grade III-V) at our hospital between 1998 and 2010. The diagnosis of VUR was made by a voiding cystourethrogram (VCUG). Renal scarring was evaluated by dimercapto-succinic acid (DMSA) scintigraphy and classified into three groups: mild (focal defects in uptake between 40 and 45%), moderate (uptake of renal radionuclide between 20 and 40%), and severe (shrunken kidney with relative uptake <20%). All associated urological anomalies were diagnosed by ultrasound or VCUG or DMSA scan.

RESULTS

Associated urological anomalies were present in 229 (13%) children. There were 87 boys and 142 girls. Duplex kidney was the main associated anomaly occurring in 148 (64.6%) of the 229 patients. Other anomalies were: bladder diverticulum in 29, solitary kidney in 12, ureterocele in 13, hypospadiasis in 11, pelviureteric junction obstruction in 9, malrotated kidney in 3, horseshoe kidney in 2, crossed fused ectopia in 1 and renal cyst in 1. DMSA scan revealed renal scarring in 105 (47.7%) of the 220 children who had a DMSA scan. 75 (50.7%) children with duplex kidneys showed renal scarring.

CONCLUSION

Associated urological anomalies occur commonly in patients with high grade VUR. Our data shows that nearly half of the patients with VUR and associated urological anomalies have renal scarring. Early recognition and treatment of VUR patients with associated urological anomalies may decrease the risk of renal parenchymal damage.

Unilateral anomalies of kidney development: why is left not right?

Abnormal renal development results in congenital anomalies of the kidney and urinary tract. As many studies suggest that renal malformations are more often found on the left side, a meta-analysis was performed on the distribution of five different unilateral anomalies: multicystic dysplastic kidney, renal agenesis/aplasia, renal ectopia, pelviureteral junction obstruction, and non-obstructive non-refluxing megaureter. Of these anomalies, the left side was affected in 53%, 57%, 56.9%, 63.2%, and 62.5% of patients, respectively, significantly different when compared with an anticipated 50% of left-sided anomalies. An exception to this left-side predominance was found in females with combined genital anomalies and unilateral renal agenesis that commonly present on the right side. The exact mechanisms leading to these lateralizations remain to be determined but may involve vascular development, differential gene expression, or susceptibility to environmental factors such as hypoxia. This remains largely speculative, however, illustrating our limited knowledge of embryogenesis in general and nephrogenesis in particular.

Urinary bladder agenesis in an alpaca (Vicugna pacos) cria

A 10-day-old female alpaca (Vicugna pacos) cria with a history of urinary straining and dribbling was presented for evaluation. The animal had markedly elevated blood fibrinogen (800 mg/dl), mildly elevated phosphorus (9.3 mg/dl), and minimally elevated blood urea nitrogen (38 mg/dl) concentrations. The total protein (5.0 g/dl) concentration was mildly decreased. These findings were suggestive of mild renal disease. An abdominal ultrasound revealed bilateral hydronephrosis and hydroureter, and no urinary bladder was identified. Gross postmortem examination revealed urinary bladder agenesis and bilateral hydronephrosis and hydroureter, with both ureters opening into a sinus in the caudal vagina. Histologic examination of the kidneys showed necrosuppurative pyelonephritis with pelvic dilation, and both ureters had mild lymphoplasmacytic and histiocytic inflammation.

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.

Yo-yo reflux in an incomplete duplex system causing severe hydronephrosis in a patient with contralateral renal agenesis

This is a report of a case of a 26-year-old patient suffering from progressive renal insufficiency with a neurogenic bladder disorder due to a lipomyelomeningocele. She had renal agenesis on the left side and grade III hydronephrosis of both segments of a right duplex kidney with a bifid ureter joining further distal to the kidney. Both ureters were dilated. The cause was found to be a yo-yo reflux between the two halves of the kidney. Following bladder augmentation and pyelopyelostomy, renal insufficiency improved to stage III and has now been stable for four years. Due to the contralateral renal agenesis, the case is a unique illustration of the functional effect of the yo-yo reflux and pyelopyelostomy.

Diagnostic approach to reflux in 2007

There is ongoing controversy regarding the association between vesicoureteric reflux (VUR), recurrent urinary tract infections (UTI), and renal damage. Despite this, routine work up for VUR is still recommended after febrile UTI in most children. The present article reviews the indications and imaging modalities available for VUR diagnosis. Alternative newer techniques like MR cystography and voiding urosonography are discussed. The increasing evidence of the role of DMSA scans in managing children with VUR is highlighted.

Developmental programming of a reduced nephron endowment: more than just a baby's birth weight

The risk of developing many adult-onset diseases, including hypertension, type 2 diabetes, and renal disease, is increased in low-birth-weight individuals. A potential underlying mechanism contributing to the onset of these diseases is the formation of a low nephron endowment during development. Evidence from the human, as well as many experimental animal models, has shown a strong association between low birth weight and a reduced nephron endowment. However, other animal models, particularly those in which the mother is exposed to elevated glucocorticoids for a short period, have shown a 20-40% reduction in nephron endowment without discernible changes in the birth weight of offspring. Such findings emphasize that a low birth weight is one, but certainly not the only, predictor of nephron endowment and suggests reduced nephron endowment and risk of developing adult-onset disease, even among normal-birth-weight individuals. Recognition of the dissociation between birth weight and nephron endowment is important for future studies aimed at elucidating the role of a reduced nephron endowment in the developmental programming of adult disease.

Renal anomalies in families of individuals with congenital solitary kidney

PURPOSE

Congenital solitary kidney affects 1 in 1000 persons, whereas bilateral renal agenesis affects 1 in 5000. Because congenital solitary kidney is increased in parents of infants with bilateral renal agenesis and fetuses with renal anomalies on ultrasound, offspring of patients with congenital solitary kidney may be at risk of both unilateral and bilateral renal anomalies. The goal was to establish empiric risk estimates for counseling individuals with congenital solitary kidney.

METHODS

Through a computerized review of records, subjects with congenital solitary kidney (defined as presumably congenital absence or severely reduced function of one kidney) were identified and asked to complete a questionnaire regarding urogenital anomalies in relatives.

RESULTS

Empiric risks of 7% for offspring, 4% for parents, and 2.5% for siblings are minimal because not all relatives underwent ultrasound studies. The incidence of bilateral renal agenesis in offspring of congenital solitary kidney probands is 0.8%, which is much greater than the population risk but less than that for families with previous bilateral renal agenesis. Concordance for type of anomaly in affected relatives is only 50%, suggesting that various anomalies included in congenital solitary kidney (agenesis, dysplasia, cystic dysplasia) may overlap. Horseshoe kidney has 80% concordance and may be a separate autosomal dominant condition.

CONCLUSION

Offspring and other relatives of individuals with congenital solitary kidney have significantly increased renal disease. Ultrasound is recommended for first-degree relatives, including fetuses at risk.

Renal anomalies in family members of infants with bilateral renal agenesis/adysplasia

Renal agenesis/adysplasia is the leading etiology of end stage renal disease in children. The etiology for renal agenesis/adysplasia has not been identified. The purpose of the present study was to determine if renal agenesis/adysplasia occur in a familial pattern. Twenty seven cases of bilateral renal agenesis/adysplasia were identified by review of autopsy records, and four were excluded. A male excess of 2.8:1 was noted with a mean gestation of 35 weeks. Prenatal and family histories were obtained on 11/23 families. Potential embryologic stressors were identified in 8/11 pregnancies. Thirty-four 1st and 2nd degree relatives from five families participated in a renal ultrasound exam. An increased prevalence of congenital renal anomalies was identified in the relatives of index patients with bilateral renal agenesis/adysplasia (14.7%) compared to controls (2.2%), with a recurrence risk of 6.2 for 1st degree relatives. The most frequently identified renal anomalies in the family members were solitary kidneys and duplicated collecting systems. The increased prevalence of a range of renal anomalies within affected families raises the possibility that isolated renal malformations result from unidentified gene-environment interactions.

Pediatric urologic imaging

Significant advances have been made in the imaging of the urinary tract in children. The trio of renal-bladder ultrasound, voiding cystourethrogram (VCUG), and nuclear scintigraphy dominate this imaging. CT and MRI, however, are rising in utility to supplement these studies and in some cases provide the definitive imaging. This article provides the radiographic findings associated with the most common pediatric urologic problems and some less common anomalies. The focus will be on ultrasound, VCUG,and nuclear studies with CT and MRI discussed as pertinent.

Blood pressure, renal function, and proteinuria in children with unilateral renal agenesis

BACKGROUND/AIM

Unilateral renal agenesis (URA) is a model for a reduced nephron number that is believed to be a risk factor for blood pressure (BP) elevation and reduced renal function. The aim of the study was to investigate BP and renal function in children with URA.

METHODS

Data on children with URA from two pediatric nephrology centers were firstly retrospectively reviewed (renal ultrasound and scintigraphy, clinical BP, creatinine clearance, urinalysis). Children with normal renal ultrasound and scintigraphy were thereafter investigated using ambulatory BP monitoring.

RESULTS

Twenty-nine children with URA were investigated--14 children with an abnormal kidney (mostly scarring) and 15 children with healthy kidneys. Hypertension was diagnosed on the basis of clinical BP in 57% of the children with abnormal kidneys and on the basis of ambulatory BP monitoring in 1 child (7%) with healthy kidneys. The mean ambulatory BP in children with normal kidneys was not significantly different from that in controls. Forty-three percent of the children with abnormal kidneys had a reduced renal function, but none of children with normal kidneys.

CONCLUSIONS

Children with abnormalities of a solitary kidney have often hypertension, proteinuria, or a reduced renal function. In contrast, children with healthy solitary kidneys have BP and renal function similar to those of healthy children.

Mixed germ cell tumor in intra-abdominal testis associated with ipsilateral ectopic dysplastic kidney

Testicular tumor of the cryptorchid testis associated with renal dysplasia is relatively infrequent and indicates maldevelopment during embryogenesis. We report a case of a 31-year-old man with a mixed germ cell tumor found in an intra-abdominal testis associated with an ipsilateral ectopic dysplastic kidney. He underwent orchiectomy with partial cystectomy. Simple nephrectomy was also performed. No evidence of disease recurrence was found at 16 months of follow-up.

Urological anomalies in children with renal agenesis or multicystic dysplastic kidney

This study aimed to determine the frequency of associated urological abnormalities in children with unilateral renal agenesis (RA) or multicystic dysplastic kidney (MCDK). In total, 38 children (10 girls, 28 boys) were studied: 21 with RA and 17 with MCDK. In 14 children (37%) anomalies of the urinary tract were suspected prenatally in ultrasound studies. In the remaining 24 children the diagnosis of RA/MCDK was made postnatally: in 13 (34%) in the first 7 days of life, in 11 (29%) at the age of 8 days to 34 months, mean 10.6+/-8.05 months. Voiding cystourethrography was done in 36 (95%) children, the isotopic 99mTc-EC/DMSA scan of the kidney in 29 (67%), and urography in 8. Urological anomalies were present in 11 (29%) children: in 7 (33%) with RA and in 4 (24%) with MCDK. Vesicoureteral reflux was diagnosed in 8 children: grade II in 4, III in 3, and IV in 1 (in 1 child to duplicated, in 1 to ectopic kidney); ureterovesical junction obstruction in 2 (9.5%); and ureteropelvic junction obstruction in 1 (4.8%). Among them, 2 children demanded surgery on the contralateral urinary tract: pyeloplasty in 1, antireflux procedure in 1; while 9 children were treated conservatively. Compensatory hypertrophy of the contralateral kidney was found in 90% of children. Thus due to an increased risk of pathological changes in the single functioning kidney, lifelong nephrological care is recommended in patients with unilateral RA/MCDK.

Segmental multicystic dysplasia and ureteropelvic junction obstruction in a nonduplicated kidney

A 2-month-old child presented for evaluation of prenatal hydronephrosis. Imaging studies were consistent with a right duplex system with a dysplastic, nonfunctioning upper pole and lower pole ureteropelvic junction obstruction. We proceeded with removal of the upper pole and pyeloplasty and were surprised to find a single collecting system with a cystic, dysplastic upper pole segment and the absence of an upper pole pelvis or ureter. The rare diagnosis of a segmental multicystic dysplastic kidney with ipsilateral ureteropelvic junction obstruction was made. We present a review of the case and of previous literature on this topic.

Factors influencing the progression of renal damage in patients with unilateral renal agenesis and remnant kidney

BACKGROUND

Although some studies have shown that the risk to develop proteinuria and renal insufficiency is increased in patients with a remnant kidney (RK) or unilateral renal agenesis (URA), other patients maintain normal renal function and negative proteinuria, and the reasons to explain these different outcomes are not known.

METHODS

We performed a retrospective study of 54 patients with a severe reduction in renal mass (33 patients with URA and 21 with RK). Follow-up was 100 +/- 72 months.

RESULTS

Twenty patients (group 1) showed normal renal function at presentation, whereas the 34 remaining (group 2) had proteinuria, and some of them renal insufficiency. Group 2 patients were older and had a higher blood pressure and BMI than group 1 patients. Eleven patients of group 1 remained normal throughout follow-up (group 1A), whereas the remaining 9 developed proteinuria/renal insufficiency (group 1B). BMI at presentation was significantly higher in group 1B: 27 +/- 3.6 kg/m(2) versus 21.6 +/- 2.6 kg/m(2), and BMI was the only factor statistically associated with the risk to develop proteinuria/renal insufficiency in group 1. Among group 2 patients, renal function remained stable in 20 (group 2A), and deteriorated (>50% increase of baseline serum creatinine) in the remaining 14 patients (group 2B). BMI at presentation and treatment with ACEI during follow-up were the only factors statistically associated with the risk for renal failure progression among group 2 patients.

CONCLUSION

Overweight plays a fundamental role in the appearance of proteinuria and renal damage in patients with severe renal mass reduction.

[Fetal genitourinary anomalies Perinatal and postnatal management with imaging techniques]

Improvements in ultrasound technology and the appropriate timing of antenatal ultrasound has led to refined prenatal diagnosis and enhanced accuracy of diagnosis of fetal renal anomalies and makes it possible to treat obstructive and/or refluxing uropathies before the onset of clinical symptoms. The third trimester renal sonography is the most important to detect hydronephrosis amenable to treatment.Classically, the prenatal diagnosis of hydronephrosis, unilateral renal agenesis, or MDKD initiates postnatal investigations, including sonography, voiding cystourethrography (VCUG), and isotopic renography. The exact degree of renal pelvic dilatation that requires full postnatal investigation is still not entirely resolved. Most authors accept the upper limit of 7 mm for the AP diameter of the renal pelvis. The US examination should be performed after the physiological dehydration period, namely 3-5 days after birth, in an urgent case on the 1st day. A meticulous ultrasound examination performed by a physician who is familiar with the renal abnormalities shows the whole extent of underlying pathology. The role of MR urography in the work-up of renal anomalies, particularly of hydronephrosis, is currently being investigated. Due to the close developmental relationship of the urinary and genital tracts, malformations frequently occur in both of these systems. Therefore in all patients, especially in girls with renal anomalies (unilateral renal agenesis, multicystic dysplastic kidney disease), the internal genitalia need to be evaluated.

The clinical significance of an empty renal fossa on prenatal sonography

OBJECTIVE

The purpose of this study was to characterize the significance of an empty renal fossa on prenatal sonography.

METHODS

A hospital database was reviewed retrospectively to find all fetuses with an empty renal fossa diagnosed on prenatal sonography between 1989 and 2003. For each case, prenatal and postnatal data were recorded.

RESULTS

Ninety-three fetuses had an empty renal fossa: 49 on the left, 41 on the right, and 3 unspecified. Forty-four fetuses were male and 29 were female. For 20, the sex was not recorded. The average gestational age at diagnosis was 29.5 weeks. Final diagnoses were made on the basis of prenatal and postnatal imaging. The missing kidney was ectopic in 39 cases (42%): 34 in the pelvis, 4 fused to the contralateral kidney, and 1 in the thorax due to a congenital diaphragmatic hernia. The absent kidney was never located in 44 cases (47%) and presumed to be congenitally absent. Ten kidneys (11%) originally thought absent were normally located, 7 of which were dysplastic, 2 normal, and 1 infiltrated by a tumor. In 39 patients (42%), other anomalies were identified, sometimes involving multiple systems, most commonly genitourinary (29) and cardiovascular (13). Of the 77 cases with the number of umbilical cord vessels recorded, 68 (88%) were normal and 9 (12%) had only 2 vessels.

CONCLUSIONS

If a kidney is not found in the renal fossa, most are either ectopic (42%) or congenitally absent (47%). An empty renal fossa is often (42%) associated with other congenital anomalies.

Associated anomalies in children with congenital solitary functioning kidney

Congenital solitary functioning kidney (CSFK) is a relatively common renal malformation and in children is frequently complicated by anomalies of the ipsilateral genital organs and occasionally by anomalies of other organs. The aim of this study was to determine the incidence of associated urological, cardiac, gastrointestinal, hematological, neurological, skeletal, and other congenital malformations in children with CSFK. We retrospectively reviewed 87 consecutive cases of CSFK diagnosed at our hospital between 1995 and 2003. There were 45 boys and 42 girls, whose ages at diagnosis ranged from newborn to 16 years (mean 4.67+/-4.48 years). In all patients, CSFK was diagnosed by abdominal ultrasound and confirmed by radionuclide studies. In 46 patients (53%) the left kidney was absent, and in 41 patients (47%) the right kidney was absent. Overall associated anomalies were detected in 52 of the 87 children (60%) with CSFK. Urological anomalies were most common, with an incidence of 37% (32/87). Nonurological anomalies were detected in 38 children (44%) with CSFK; these included cardiac anomalies in 13, gastrointestinal anomalies in eight, hematological anomalies in five, neurological anomalies in three, and other organ anomalies in nine. In our study, more than half of the patients with CSFK had associated anomalies. For this reason we recommend abdominal ultrasound and voiding cystourethrogram for early recognition of urological anomalies and a careful physical examination for other organ anomalies in patients with CSFK.

Natural history of vesicoureteral reflux associated with kidney anomalies

OBJECTIVES

To evaluate the cystographic follow-up of patients with multicystic dysplastic kidney (MCDK), renal agenesis, and renal ectopia with associated primary vesicoureteral reflux (VUR).

METHODS

Patients with primary associated VUR (grade 2 or more) and with a minimal follow-up of 24 months were included in this study.

RESULTS

Of the children with renal agenesis, 24% had VUR. The median grade of VUR was significantly greater in the boys than in the girls (4 versus 2, respectively; P < 0.05). All girls and 34% of the boys experienced spontaneous resolution 1 year after diagnosis; 66% of the boys required operative treatment. Of the patients with MCDK, 16% had VUR. The median grade of VUR in the kidney contralateral to the MCDK was greater in the boys than in the girls (3.5 versus 2, respectively; P = 0.06). All girls and 60% of the boys had spontaneous resolution 1 year after diagnosis; 40% of the boys underwent operative treatment. Of the children with renal ectopia, 30% had VUR. The median grade of VUR for the refluxing unit was significantly greater in the girls than in the boys (3 versus 2, respectively; P < 0.05). Spontaneous resolution of VUR was observed in all boys (66% at 1 year) and in 40% of the girls; 60% of the girls required operative treatment.

CONCLUSIONS

Spontaneous resolution of VUR can be anticipated in girls with MCDK or renal agenesis and in boys with renal ectopia. These data can be used in planning the proper follow-up schedule for babies with a kidney anomaly detected by ultrasonography.

Wilm's tumor in a solitary kidney complicated by chemotherapy induced obstructive uropathy

A three-year-old male child with Wilm's tumor of left kidney and right sided unilateral renal agenesis is reported. The left renal vein was located posterior to the aorta. He was managed with medical measures alone. The initial phase of treatment was complicated by chemotherapy induced dislodgment of the tumor fragment and subsequent distal obstruction.

Associated urologic anomalies in children with solitary kidney

PURPOSE

The aim of this study was to investigate the incidence, nature, surgical treatment, and outcome of associated urologic anomalies (AUA) in children with anatomic or functional solitary kidney (SK).

METHODS

In this study, SK was defined as the kidney that is present in cases of unilateral renal agenesis (RA), or the kidney that is contralateral to a kidney that is nonfunctional secondary to either noncystic dysplastic kidney disease (NCDK), or multicystic dysplastic kidney disease (MCDK). Fifty-seven consecutive patients with SK (17 owing to RA, 10 owing to NCDK, 30 owing to MCDK) were reviewed.

RESULTS

A total of 23 of 57 (40%) had AUA in the SK (11 of 17 [65%] of RA cases; 7 of 10 [70%] of NCDK cases; and 5 of 30 [17%] of MCDK cases). The incidence of AUA in MCDK was significantly lower than that in RA or NCDK (p <.01: Mann-Whitney U test). Surgery was performed on 20 of 23 (87%) for vesicoureteric reflux (VUR) in 13, pelviureteric junction stenosis in 3, and ureterovesical junction stenosis in 4. Surgery was not performed in 3 of 16 with VUR because the VUR that was present was of low grade. AUA-related symptoms such as urinary tract infection and abdominal mass were seen in 15 of 23; the remaining 8 were asymptomatic. Mean age at surgery was 4.8 years. There were no operative or postoperative complications, and all cases are well without impaired renal function or hypertension after a mean follow-up period of 5.3 years.

CONCLUSIONS

In patients with SK, 40% had AUA in the renal collecting system of the SK. All children with SK should undergo a screening voiding cystourethrography (VCUG) even in the absence of hydronephrosis or UTI, and early recognition and treatment are imperative to decrease the long-term risk for renal damage.

Squamous cell carcinoma at herniorrhaphy and unilateral renal agenesis

Unilateral renal agenesis occurs infrequently. However, it has been associated with malignancies at multiple primary sites, anomalies of the genitourinary system, and supernumerary limbs. We present the case of a 60-year-old man with an incarcerated left inguinal hernia and renal insufficiency. At herniorrhaphy, he had squamous cell carcinoma in the hernia sac. A postoperative evaluation revealed unilateral renal agenesis, stage IV squamous cell carcinoma of the urinary bladder, and urolithiasis. The clinician should consider the genitourinary system as a primary site when patients present with the unusual finding of squamous cell carcinoma in the abdominal cavity and unilateral renal agenesis.

[Unilateral agenesis of structures dependent on the mesonephric duct. Presentation of a case]

The mesonefric duct plays an essential role in the development of the genitourinary tract. From that duct derive structures as the ureter, the vas deferens and the seminal vesicles. Also, the ureteral bud interact with the mesonefric blastema and induce its conversion to renal tissue. The origin of these anomalies of the embrionary development is unknown. In some cases, mutations on the gene of the cystic fibrosis (CFRT) could play a role, assuming that there is a relationship between the congenital absence of the vas deferens and the cystic fibrosis. Usually, the absence of these structures has a silent course. Thus, the most important diagnostic factor is the clinical suspicion. The knowledge of this association can lead to the diagnosis of other congenital abnormalities. In addition, it is important to know that these anomalies could be present isolated as expression of other non-urological diseases, specially the cystic fibrosis, the most common hereditary disease between the Caucasian race.

Renal aplasia is the predominant cause of congenital solitary kidneys

BACKGROUND

Congenital solitary kidneys, which are susceptible to renal failure, have been considered mostly due to unilateral renal agenesis and partly due to renal aplasia. Risk of familial recurrence and of other associated anomalies is known to be much higher in renal agenesis than in renal aplasia. However, differential diagnosis between the two renal anomalies is difficult, and renal agenesis has been found much less frequently in ultrasound screening studies of fetuses than in autopsy studies.

METHODS

In order to investigate the nature and incidence of the congenital solitary kidney, the present study performed ultrasound screening of the kidneys in 4000 newborn babies. A diagnosis of renal agenesis was made when ultrasound identified no renal parenchyma and renoscintigraphy showed no renal function, and renal aplasia when there was a renal parenchyma without any function.

RESULTS

Primary screening detected 52 babies suspected of having small kidneys and one baby with a multicystic dysplastic kidney, but no baby with renal agenesis. Forty-seven of the 53 babies underwent a second ultrasound scanning at one month of age. Three small kidneys in three babies further decreased in size, had no function and were diagnosed as renal aplasia (which has an incidence rate of one in 1300). Follow-up ultrasound studies showed further regression in all three, which became very hard to distinguish by one year of age.

CONCLUSIONS

The present study showed that ultrasound in the neonatal period could identify the aplastic kidney, which had a reniform shape, not rudimentary, during the newborn period, and regressed rapidly thereafter. These findings indicate that most renal agenesis diagnosed clinically thus far might more correctly be renal aplasia.

Reflux nephropathy in infancy: a comparison of infants presenting with and without urinary tract infection

PURPOSE

We compared the incidence of renal scarring in infants with high grade vesicoureteral reflux in those presenting with and without urinary tract infection.

METHODS AND METHODS

We reviewed the medical records of 81 male and 46 female infants (194 renal refluxing units) with a mean age of 4 months who had grade IV or V primary vesicoureteral reflux and underwent an anti-reflux procedure between 1984 and 1997. Dimercapto-succinic acid (DMSA) scans and voiding cystourethrography were performed in all cases. Patients were followed for 2 to 16 years, including 90% for greater than 3 years. Renal ultrasound and DMSA scan were done at followup.

RESULTS

A total of 97 patients (76%) (148 refluxing renal units) presented clinically with urinary tract infection. The initial DMSA scan demonstrated renal scarring in 40 of the 106 grade IV (38%) and 28 of the 42 grade V (67%) refluxing renal units. There was no scarring on followup in previously normal refluxing renal units. Of the patients 30 (24%) (46 refluxing renal units) were diagnosed before a urinary tract infection developed, 16 underwent screening due to vesicoureteral reflux in a sibling and in 10 reflux was initially suspected due to hydronephrosis on prenatal ultrasound. In the remaining 4 patients vesicoureteral reflux was suspected during abdominal ultrasound to investigate abdominal pain, jaundice, associated hypospadias and fetal alcohol syndrome, respectively. DMSA scan showed evidence of scarring in 6 of 21 grade IV (29%) and 9 of 25 grade V (36%) refluxing renal units in this group. Followup revealed scarring in only 1 previously normal refluxing renal unit.

CONCLUSIONS

The incidence of reflux nephropathy in primary grade V vesicoureteral reflux is lower in cases detected by screening and with treatment it remained lower than in cases of urinary tract infection that presented clinically. Early treatment of grade V vesicoureteral reflux made possible by screening may prevent renal damage.