Update on Multicystic Dysplastic Kidney

Outcome of children with multicystic dysplastic kidney: Does involved side matter?

BACKGROUND

Multicystic dysplastic kidney (MCDK) is a common anomaly detected on antenatal ultrasound. We aimed to assess the profile of children with MCDK and to investigate whether the involved side has any effect on outcome.

METHODS

Thirty-nine patients with MCDK and 20 controls were enrolled. Patients who estimated glomerular filtration rate (eGFR) values over 90 mL/min/1.73 m2 were compared with controls. Comparison was made between the involved sides.

RESULTS

MKDB was right-sided in 20 (51.3%) and left-sided in 19 (48.7%) patients. 33.3% had additional urinary tract abnormality, 10.2% had systemic abnormality. 82% showed contralateral kidney enlargement. 48.7% involuted, 17.9% underwent nephrectomy. 35.8% suffered from urinary tract infection (UTI). 5.1% had renal scarring (RS). 30% developed microalbuminuria. 12.8% complicated with hypertension. 17.9% progressed to chronic kidney disease (CKD). Hypertension was independent risk factor for developing CKD. Blood pressure, cystatin C and urine microalbumin/creatinine levels were increased, and eGFR values were decreased in patients compared to controls. No significant difference was found between the two sides for rates of involution, UTI, RS, nephrectomy, and additional abnormality. Cystatin C levels were higher on the right than left sides (p = .033).

CONCLUSION

Children with MCDK predispose to renal deterioration even at normal eGFR values. Although cystatin C levels tended to increase in right-sided patients, the involved side seemed to have no significant effect on renal outcome. Hypertension was main determinant for progression to CKD in MCDK.

GFR measurements and ultrasound findings in 154 children with a congenital solitary functioning kidney

BACKGROUND

Multicystic dysplastic kidney (MCDK) and unilateral renal agenesis (URA) are the most common reasons for a congenital solitary functioning kidney (SFK). We aimed to assess the presence of abnormalities in the congenital SFK and evaluate kidney function using chrome EDTA (CrEDTA) measurements.

METHODS

We retrospectively reviewed the medical records of 154 children with MCDK and URA in the period from 2005 to 2022 to analyze results from ultrasound scans and CrEDTA glomerular filtration rate (GFR) examinations.

RESULTS

Of 154 children with a solitary kidney due to MCDK (62%) or URA (38%), abnormalities on the congenital SFK were found in 13 children (8%). The abnormalities spontaneously resolved in 6 children (46%). The most common abnormality was hydronephrosis. Compensatory hypertrophy was found in 17% of the children within the first 6 months of life. 116 children (90%) had a standard GFR (sdGFR) above 75% of expected for the age. Out of those with a sdGFR below 75% of expected, 3 (23%) had abnormalities in the congenital SFK. There was no difference in sdGFR between children with MCDK and URA.

CONCLUSIONS

Our study is the first using CrEDTA for GFR measurements and suggests that most children with a congenital SFK due to MCDK or URA have a kidney function within expected for the age. Compensatory hypertrophy of the SFK is found in a minority of children within the first six months of life, suggesting that this process is developing over time. The prevalence of abnormalities in the SFK seems low, however those with abnormalities (e.g. hydronephrosis) are at higher risk of reduced sdGFR.

Ipsilateral renal dysgenesis or agenesis with tubulocystic anomalies of the mesonephric duct

Tubulocystic anomalies of the mesonephric duct (MND) are a rare group of related entities with a perplexing clinical presentation. Ultrasound is a useful screening investigation, which can help identify a dysplastic kidney or point to renal agenesis and identify cystic or tubulocystic changes in the structures derived from the ureteric bud or MND. Further evaluation with MRI can help in characterisation and direct management. The presence of a dysplastic kidney or absence of a kidney should prompt further evaluation for associated ureteric abnormalities such as ectopic insertion or ureterocoele, which could lead to a diagnosis of tubulocystic anomaly of the MND.

Contribution

The authors describe two cases, briefly outline the diagnostic approach and summarise the literature on management. Reporting radiologists should be aware of these entities.

Fetal uropathies: pre- and postnatal imaging, management and follow-up

Congenital uropathies are the most common fetal anomalies. They include a wide spectrum of anomalies ranging from mild pelvis dilation to complex urinary tract malformations. Prenatal imaging not only allows for their diagnosis but, in experienced hands, it can differentiate obstructive from refluxing or malformative uropathies. Such precise prenatal information allows for intervention before birth in select cases or for adapting the postnatal workup to provide a better long-term outcome. For the different types of congenital uropathies, we describe their prenatal presentations on US and the complementary role of fetal MRI where indicated. We correlate these findings with postnatal workup and summarize the updated neonatal diagnostic and clinical/surgical management.

Cystic Kidney Diseases That Require a Differential Diagnosis from Autosomal Dominant Polycystic Kidney Disease (ADPKD)

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary cystic kidney disease, with patients often having a positive family history that is characterized by a similar phenotype. However, in atypical cases, particularly those in which family history is unclear, a differential diagnosis between ADPKD and other cystic kidney diseases is important. When diagnosing ADPKD, cystic kidney diseases that can easily be excluded using clinical information include: multiple simple renal cysts, acquired cystic kidney disease (ACKD), multilocular renal cyst/multilocular cystic nephroma/polycystic nephroma, multicystic kidney/multicystic dysplastic kidney (MCDK), and unilateral renal cystic disease (URCD). However, there are other cystic kidney diseases that usually require genetic testing, or another means of supplementing clinical information to enable a differential diagnosis of ADPKD. These include autosomal recessive polycystic kidney disease (ARPKD), autosomal dominant tubulointerstitial kidney disease (ADTKD), nephronophthisis (NPH), oral-facial-digital (OFD) syndrome type 1, and neoplastic cystic kidney disease, such as tuberous sclerosis (TSC) and Von Hippel-Lindau (VHL) syndrome. To help physicians evaluate cystic kidney diseases, this article provides a review of cystic kidney diseases for which a differential diagnosis is required for ADPKD.

Should we screen for Müllerian anomalies following diagnosis of a congenital renal anomaly?

INTRODUCTION

Despite the well-established embryological relationship in the development of renal and Müllerian structures, no clear guidelines exist regarding screening for Müllerian anomalies (MA) in the setting of a renal anomaly (RA). Delayed diagnosis of MA can have significant reproductive consequences.

OBJECTIVE

To investigate the prevalence of coexisting MA in patients with congenital RA.

STUDY DESIGN

This is a retrospective cohort study of females age 12-35 years with a diagnosis of RA, identified by diagnosis codes, who were followed for care between 2013 and 2020. Data were collected on demographics, medical history, clinical presentation, and imaging studies. Descriptive statistics were used to summarize the data. This study was IRB approved.

RESULTS

A total of 465 patients were included in this study, of whom 326 patients (70.3%) had a pelvic evaluation during the study period. Of these 326 patients, 125 (38.3%) were found to have coexistent MA. About one-third of patients who underwent pelvic evaluation due to pain were found to have MA. For 69.6% (87/125) of patients with MA, the RA was diagnosed prior to the MA. The average age at time of RA diagnosis was 6.4 ± 8.8 years and the average age of MA diagnosis was 16.4 ± 6.9 years. Forty-eight (38.4%) patients had obstructive anomalies. Of the Müllerian obstructions, 93.8% were treated with urgent surgery and the remainder started on hormonal suppression. The prevalence of MA was dependent on the RA diagnosis (Figure). Of patients with a solitary kidney, 67.1% were diagnosed with MA. For other parenchymal RA, the prevalence of MA was 20-23%. In patients with solitary kidney, uterus didelphys was the most common MA (52.1%). Thirty percent of patients with a solitary kidney were diagnosed with an obstructive MA.

CONCLUSIONS

In this study, 38% of patients with RA who underwent a pelvic evaluation were found to also have MA. Our study shows the strongest association between MA and solitary kidney, but also emphasizes a significant risk with other RA. Almost 40% of patients with diagnosed MA were found to have an obstruction that required urgent treatment. Delays in diagnosis and treatment of Müllerian obstructions can be detrimental for future reproductive health, due to risk of chronic pain, infertility, infection, and endometriosis. Given the high prevalence of MA in patients with RA, especially those with congenital solitary kidney, routine screening with pelvic ultrasound should be performed around the age of expected menarche.

Utility of renal scintigraphy in diagnosis of multicystic dysplastic kidney

PURPOSE

To compare the prevalence of vesicoureteral reflux (VUR), febrile urinary tract infection (fUTI), and chronic kidney disease (CKD) among patients with multicystic dysplastic kidney (MCDK) diagnosed by renal scintigraphy (RS) versus follow-up renal ultrasound (RUS) alone.

METHODS

This was a retrospective review of patients seen at a tertiary care center from 2010 to 2020 with MCDK diagnosed by RS or follow-up RUS. Differences in the prevalence of VUR, fUTI, and CKD by cohort were assessed using logistic regression analysis, Pearson X² , and Fisher's Exact tests. Temporal trends in diagnostic methods used (RUS versus RUS + RS) were evaluated using the Cochran-Armitage trend test.

RESULTS

One-hundred seventy-two patients were included: 50% (n = 86) underwent RUS + RS and 50% (n = 86) underwent RUS alone to diagnose MCDK. Prevalence of VUR, fUTI, and CKD did not significantly vary between groups. Among patients who had a VCUG, 4.4% had contralateral VUR (1.7% RUS + RS group; 7.4% RUS group; p = 0.19) and 14.5% had at least one fUTI (16.3% RUS + RS group; 12.8% RUS group; p = 0.52). Females were significantly more likely to have at least one fUTI (p = 0.04). Four patients (2.3%) developed CKD, all in the RUS + RS cohort (p = 0.12). Diagnosis of MCDK by RUS versus RUS + RS did not significantly vary over time (p = 0.17).

CONCLUSION

Patients with unilateral MCDK confirmed by RS versus RUS alone do not significantly vary in the prevalence of VUR, fUTI, or CKD. Renal scintigraphy studies may not be necessary in unilateral MCDK diagnosis but continue to be used.

Unusual association of Wilms' tumor with cystic diseases of kidney: A pathologic surprise

Wilms' tumor (or nephroblastoma) is the most common renal malignancy in the pediatric population which consists of blastemal, epithelial, and stromal elements in variable proportions. The occurrence of renal cysts in children and infants is a rare phenomenon and is possibly an outcome of developmental aberrations in mesonephric blastema. The coincidental association of nephroblastoma with renal cysts is a very rare finding. Here, we describe two cases of Wilms' tumor with an unusual association between glomerulocystic kidney disease and multicystic dysplastic kidney.

Multicystic Dysplastic Kidney: Prenatal Compensatory Renal Growth Pattern

OBJECTIVES

To assess the prenatal growth pattern of the normal kidney contralateral to a multicystic dysplastic kidney (MCDK).

METHODS

A retrospective study was conducted in a single referral center over 4 years. Cases diagnosed prenatally as MCDK and confirmed postnatally constituted the study group. For creation of nomograms, only isolated cases of MCDK were included.

RESULTS

Sixty-one fetuses had a diagnosis of an MCDK during the study period. After exclusion of cases with associated malformations, 47 fetuses remained, providing 94 measurements for creation of nomograms. The growth pattern of the normal kidney contralateral to an MCDK was linear throughout gestation (percentile = 20.01 + 1.5 gestational age; linear R²  = 0.753; r = 0.868) and was significantly higher during the third trimester (29-38 weeks' gestation) compared to the second trimester (22-28 weeks' gestation; P < .001). A comparison of the growth pattern of the normal kidney contralateral to the MCDK to the growth pattern of a solitary kidney revealed a significant higher compensatory trend during the third trimester (P < .0001). The mean kidney lengths at 22 and 38 weeks' gestation correlated with the 52nd and 88th and with the 84th and 90th percentiles for the normal kidney contralateral to the MCDK and a solitary kidney, respectively.

CONCLUSIONS

According to our study, the normal kidney contralateral to an MCDK has a unique growth pattern during intrauterine life, with dominant growth during the third trimester. The exact mechanism for this pattern, in comparison to early renal hypertrophy shown in solitary kidneys, is currently not clear. These data provide relevant information for the multidisciplinary prenatal counseling of future parents regarding the future renal outcome.

Renal function in children with a congenital solitary functioning kidney: A systematic review

INTRODUCTION

Abnormal renal development that results in lack of function or development of one of two kidneys is known as congenital solitary functioning kidney (CSFK). Two well characterized sub-categories of CFSK are unilateral renal agenesis (URA) and multicystic dysplastic kidney (MCDK). This systematic review sought to evaluate the change in renal function in children ≤18 years old with a CSFK as a result of URA or MCDK.

METHODS

A literature search in MEDLINE and Embase was conducted (1946 to July 13, 2020). All relevant articles were retrieved and evaluated based on pre-selected criteria by two independent researchers. Data was then extracted from variables of interest and conflicts were resolved by a third researcher. The primary outcome was renal function, and the secondary outcomes were proteinuria and hypertension.

RESULTS

Forty-five studies were included, of which 49% (n = 22) were retrospective and/or 58% (n = 26) were cohort studies. A combined total of 2148 and 885 patients were diagnosed with MCDK or URA, respectively. The proportion of children with worsened renal function at follow-up was found to be 8.4% (95% CI: 5.2%-13.4%). Among the studies reporting renal function as a group mean or median at follow-up, 84% (21/25) had a GFR/CrCl above 90 (mL/min/1.73  m²/ml/min). In terms of secondary outcomes, the proportion of children with proteinuria and hypertension was found to be 10.1% (95% CI: 6.9%-14.6%) and 7.4% (95% CI: 5.0%-10.9%), respectively.

CONCLUSION

The risk of developing proteinuria (10.1%), hypertension (7.4%), and/or worsened renal function (8.4%) for children with CFSK as a result of MCDK or URA is low. However, the level of evidence in the literature is weak. Further research is needed to identify the predisposing factors that may differentiate the small subset of children with CSFK at a higher risk of developing adverse renal outcomes.

Effects of low-dose oxygen administration on renal blood oxygenation level-dependent MRI in children with glomerulonephritis

OBJECTIVE

Children are often sedated for renal blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) and may require low-dose oxygen administration. It is unclear whether low-dose oxygen administration affects results of BOLD MRI. We investigated the effect of low-dose oxygen administration on renal BOLD MRI and its variation by the presence or absence of renal disease.

MATERIALS AND METHODS

We retrospectively examined children undergoing MRI for renal disease between 2013 and 2020. Patients were divided into glomerulonephritis and non-glomerulonephritis groups; spin relaxation time (T2*) was determined using a 3.0 T MRI system.

RESULTS

The study included 10 children (5 patients in each group); patient characteristics between the groups did not differ significantly. In the entire cohort, oxygen administration reduced mean spin relaxation rate (R2*) value in the medulla (p < 0.04). The mean R2* value decreased with oxygen administration in the non-glomerulonephritis group, whereas this was not observed in the glomerulonephritis group. The responses to oxygen administration of the two groups differed significantly in the cortex (p < 0.05) and medulla (p < 0.02).

DISCUSSION

Low-dose oxygen administration affects the results of BOLD MRI. We suggest that understanding the fluctuations due to oxygen administration is useful in monitoring the disease activity of glomerulonephritis.

Retrospective evaluation of the pediatric multicystic dysplastic kidney patients: experience of two centers from southeastern Turkey

Background/aim

The objective of this study is to determine the clinical features of unilateral multicystic dysplastic kidney (MCDK) patients.

Materials and methods

The demographic, clinical, laboratory, and radiologic features of MCDK patients at Diyarbakır Children’s Hospital and Diyarbakır Gazi Yaşargil Training and Research Hospital between January 2008-June 2019 were retrospectively evaluated.

Results

A total of 111 [59 (53.2%) male and 52(46.8%) female] patients with MCDK were followed for a mean period of 41.89 ± 32.03 months. MCDK was located on the left and right sides in 46 (41.4%) and 65 (58.6%) of the children, respectively (p > 0.05). A total of 87 (78.4%) patients had antenatal diagnosis. The mean age at diagnosis was 13.7 ± 34.2 months. Of the 49 voiding cystourethrogram (VCUG)-performed patients, vesicoureteral reflux was detected in 11 patients (22.4%). Other associated urological anomalies in the patients were detected in 12 (10.8%) patients. On Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy which was performed in all patients showed scarring in four children. Eight patients had history of UTI (7.2%). Renal failure, hypertension, and proteinuria were diagnosed in three children (2.7%). Sixty-nine (62%) patients developed compensatory hypertrophy.

Conclusion

All cases should be followed up closely and VCUG should be reserved for patients with recurrent UTI and other urological problems indicated by ultrasonography and abnormal DMSA scan results.

Approach to the postnatal sonographic evaluation of prenatally detected abdominopelvic cysts

Prenatally detected abdominal and pelvic masses are commonly cystic in morphology and usually seen on mid-trimester sonography. Sonography is the favored imaging modality for the postnatal evaluation of these lesions in newborns, given its availability, low cost, lack of ionizing radiation, lack of sedation, and high spatial resolution in small patients. The differential diagnosis of abdominopelvic cystic masses in newborns is broad given that they can arise from many organs and may have overlapping features on imaging. This article illustrates an approach to the postnatal sonographic evaluation of prenatally detected cystic abdominal and pelvic masses based on their anatomic location and distinctive sonographic characteristics, which can aid in an accurate diagnosis and guide appropriate management.

Expression Pattern of α-Tubulin, Inversin and Its Target Dishevelled-1 and Morphology of Primary Cilia in Normal Human Kidney Development and Diseases

The spatiotemporal expression of α-tubulin, inversin and dishevelled-1 (DVL-1) proteins associated with the Wnt-signaling pathway, and primary cilia morphology were analyzed in developing kidneys (14th–38th developmental weeks), healthy postnatal (1.5- and 7-years old) and pathologically changed human kidneys, including multicystic dysplastic kidneys (MCDK), focal segmental glomerulosclerosis (FSGS) and nephrotic syndrome of the Finnish type (CNF). The analysis was performed by double immunofluorescence, electron microscopy, semiquantitative and statistical methods. Cytoplasmic co-expression of α-tubulin, inversin and DVL-1 was observed in the proximal convoluted tubules (pct), distal convoluted tubules (dct) and glomeruli (g) of analyzed tissues. During kidney development, the overall expression of α-tubulin, inversin and DVL-1 decreased, while in the postnatal period slightly increased. The highest expressions of α-tubulin and inversin characterized dct and g, while high DVL-1 characterized pct. α-tubulin, inversin and DVL-1 expression pattern in MCDK, FSGS and CNF kidneys significantly differed from the healthy control. Compared to healthy kidneys, pathologically changed kidneys had dysmorphic primary cilia. Different expression dynamics of α-tubulin, inversin and DVL-1 during kidney development could indicate that switch between the canonical and noncanonical Wnt-signaling is essential for normal kidney morphogenesis. In contrast, their disturbed expression in pathological kidneys might be associated with abnormal primary cilia, leading to chronic kidney diseases.

Ultrasound Imaging of Renal Cysts in Children

Renal cysts can be focal or diffuse and unilateral or bilateral. In childhood, most renal cysts are due to hereditary diseases rather than simple cysts or acquired cystic diseases, unlike adults. Inherited cystic diseases can be ciliopathies due to a primary ciliary defect (as in polycystic kidney diseases and nephronophthisis). Acquired causes include obstructive cystic dysplasia, dyselectrolytemia, and acquired cysts in renal replacement therapy. The final diagnosis requires a multispecialty approach, including radiology, pathology, and genetics. Imaging is a very important component in treating patients with cystic renal diseases. This article discusses the ultrasound findings of cystic renal diseases in children, along with a brief discussion of other imaging modalities and a suggested ultrasound reporting format.

Renal cystic diseases during the perinatal and neonatal period

Renal cystic diseases are a clinically and genetically diverse group of renal diseases that can manifest in utero, infancy, or throughout childhood and adulthood. These diseases may be unilateral or bilateral with a single cyst or multiple cysts, or with increased echogenicity of the renal cortex without macroscopic cysts. Certain cystic renal diseases are life-threatening, with many developing chronic kidney and hepatic disease if not recognized early enough. Therefore, due to the prevalence and life-altering complications of this specific group of diseases in vulnerable populations, it is crucial for clinicians and healthcare providers to have an overall understanding of cystic diseases and how to pre-emptively detect and manage these conditions. In this review, we discuss in detail the epidemiology, genetics and pathophysiology, diagnosis, presentation, and management of numerous genetic and sporadic renal cystic diseases, such as polycystic kidney disease, multicystic dysplastic kidney, and calyceal diverticula, with an emphasis on prenatal care and pregnancy counseling.

Side predilection in congenital anomalies of the kidney, urinary and genital tracts

BACKGROUND

There appear to be various patterns of sidedness with relation to the common urogenital malformations observed in pediatric urology. The objective of this statistical review was to synthesize this data and to assess if these patterns are significant.

MATERIALS AND METHODS

Eighteen urogenital conditions were investigated and for each condition the five largest studies that noted laterality were included. The sidedness of each condition was then analysed for statistical significance.

RESULTS

Three conditions had a statistically significant higher proportion on the right side: palpable undescended testis (63%, p = 0.0002), inguinal hernia (59%, p = 0.0001) and hydrocele (60%, p = 0.003). Three conditions were significantly more common on the left side: impalpable undescended testis (59%, p = 0.0008), renal agenesis (54%, p = 0.02) and vesico-ureteric junction obstruction (71%, p < 0.0001) while both pelvi-ureteric junction obstruction (62%, p = 0.09) and absent vas deferens (61%, p = 0.11) were trending towards significance.

CONCLUSIONS

Various urogenital malformations display a predilection for one side. Proximal malformations tend to be more frequently seen on the left side, where as inguinoscrotal malformations are more frequently observed on the right. There is an increasing body of literature regarding aetiological factors for these conditions. However, our current understanding of the pathophysiology of these conditions does not completely explain this pattern of observation.

Multicystic dysplastic kidney - treat each case on its merits

OBJECTIVES

To assess outcomes of unilateral multicystic dysplastic kidney (MCDK) managed at an Australasian centre over a 15 year period. To assess if MCDK involution could be predicted based on change noted between first two postnatal ultrasound scans 6 months apart.

SUBJECTS AND METHODS

A retrospective study was performed.

RESULTS

One-hundred-and-six cases of unilateral MCDK were studied. Eighty-four of these presented antenatally. Twenty-two MCDK cases presented postnatally. Urological anomalies associated with MCDK included vesicoureteric reflux (VUR), ureterocele and contralateral pelviureteric junction obstruction (PUJO). Children undergoing surgical intervention for these anomalies were offered concurrent MCDK nephrectomy. Morbidity associated with MCDK under surveillance included febrile culture-positive urinary tract infection in 20 cases (20.7%), hypertension in four (3.7%) and Wilms' tumor in one (0.9%). Thirty-six cases (34%) underwent complete involution, 32 (30.2%) were in the process of involuting and 38 cases (35.8%) underwent nephrectomy because of failure of involution or associated morbidity. If the MCDK reduced in cranio-caudal interpolar length by 20% or more between the first postnatal USS and the next one 6 months later, then it was very likely to involute spontaneously. If the MCDK did not reduce in cranio-caudal interpolar length by 20% between the first postnatal scan and the next one 6 months later, then it was highly likely to fail to involute, and in our study, correlated with the outcome of nephrectomy.

CONCLUSION

Although MCDK is a benign condition, it should be carefully investigated and followed-up, as involution may not occur in over a third. In some cases, morbidity may occur. Each case of MCDK should be managed on its own merits.

LEVEL OF EVIDENCE

Level II - Prognosis study, Retrospective.

Voiding Cystourethrogram in Children With Unilateral Multicystic Dysplastic Kidney: Is It Still necessary?

OBJECTIVE

To evaluate the value of the voiding cystourethrogram (VCUG) in children with multicystic dysplastic kidney (MCDK) who have a normal versus abnormal contralateral kidney and bladder ultrasound (US), and assess the risk of having vesicoureteral reflux (VUR) or urinary tract infection (UTI) based on the US results.

METHODS

A retrospective chart review including children with unilateral MCDK with postnatal US and VCUG available at our institution between January 2008 and September 2017 was performed. Analysis was done to find association between abnormal contralateral US and contralateral VUR and UTI.

RESULTS

One hundred and fifty-six children were analyzed; 118(75.6%) patients had a normal contralateral kidney US, while 38(24.4%) had abnormal US. The rate of severe contralateral VUR (grade IV and V) was 2 (1.7%) and 5 (13.2%) in children with normal and abnormal contralateral US, respectively. The risk analysis demonstrated a significant association between severe VUR on the contralateral kidney and an abnormal contralateral US (odds ratio = 7.73; 95%CI: 1.43-41.81; P = 0.018) and no significant association with UTI (odds ratio = 1.58; 95%CI: 0.50-4.94; P = 0.435).

CONCLUSION

Our data suggests, the rate of severe contralateral VUR in children with unilateral MCDK and normal contralateral kidney is low. VCUG should be considered for infants with proven MCKD and alterations on the contralateral kidney on US. Following patients with MCDK and normal contralateral kidney without the use of VCUG is a reasonable approach, unless there is development of signs and symptoms of recurrent UTI or deterioration of the renal function. We found that abnormal contralateral kidney US was associated with severe VUR.

"Watch and Wait" Strategy for Multicystic Dysplastic Kidney (MCDK): Status Survey of Perceptions, Attitudes, and Treatment Selection in Chinese Pediatric Urologists and Pediatric Surgeons

To investigate the perceptions, attitudes, and treatment selection of Chinese pediatric urologists and pediatric surgeons regarding a "watch and wait" strategy for multicystic dysplastic kidney (MCDK). We used a cross-sectional survey in this study. We sent the questionnaire to pediatric urologists and pediatric surgeons to capture their views via the "Questionnaire Star" online survey platform between November and December 2019. The questionnaire contained the basic information and surgical experiences of the respondent, respondents' awareness regarding the counseling of prenatally-diagnosed MCDK and the treatment of MCDK, and respondents' knowledge regarding the imaging modalities, frequency, and duration of follow-up. Of the 200 questionnaires we sent, we received 151 responses. Of those 151 complete responses, most respondents were women (n = 104, 68.9%), pediatric urologists (n = 78, 51.6%), and practicing with at least 5 years of surgical experience (n = 112, 74.2%); 11.9% reported >20 years' experience. Eighty-two surgeons (54.3%) provided positive counseling for prenatally-diagnosed MCDK. Ninety-nine surgeons (65.6%) advocated conservative management for MCDK, and only 14.8% of respondents suggested limiting the use of radiographic evaluation for MCDK. Surgeons working in academic teaching facilities and those from East China were more likely to select a "watch and wait" strategy. Chinese pediatric urologists and pediatric surgeons have inadequate knowledge of the "watch and wait" strategy for MCDK. An expert consensus on the strategy of "watch and wait" for MCDK in China is urgently needed to promote the application of this non-surgical treatment mode in clinical practice. A larger sample size is required to fully identify the current opinion of Chinese pediatric urologists and pediatric surgeons regarding the management of MCDK.

Tubulocystic anomalies of the mesonephric duct associated with ipsilateral renal dysgenesis

INTRODUCTION

Renal agenesis and multicystic dysplastic kidney (MCDK) are usually associated with either an absent or atretic ureter. Occasionally, these renal anomalies may be associated with a dilated tortuous ureter, ureterocele or other cystic malformation of mesonephric duct (MND) remnants.

OBJECTIVES

The objective of this study was to identify and classify anatomical variants of tubulocystic remnants of the MND, with a secondary focus on natural history and management outcomes.

PATIENTS AND METHODS

A retrospective cohort study of patients seen in the study institution between 2007 and 2014 with a tubulocystic abnormality of MND structures associated with either MCDK or renal agenesis was conducted. Medical imaging and progress notes were reviewed for all patients. Data collected included anatomical information, surgical intervention, histology and outcomes of both conservatively managed and surgically resected MND remnant structures.

RESULTS

Nineteen patients were identified, 5 girls and 14 boys. Median age at presentation was 4.6 years. Anomalies of the MND occurred on the left in 9 patients and on the right in 10 patients. Mean follow-up was 3.4 years. Patients fell into 3 distinct anatomical groups: Type I, including orthotopic remnants corresponding to ureteric bud structures (ureter and trigone); Type II, including ectopic MND remnants of ureteric bud structures, and Type III, including complex remnants corresponding to MND structures other than those from ureteric bud (vas, epididymis and seminal vesicles). Anomalies of structures arising from urogenital sinus and paramesonephric ducts were also identified. Most patients were asymptomatic and successfully managed conservatively. Transvesical puncture of trigonal cysts provided effective decompression in 5 patients. Partial or complete MCDK regression was seen in 7 patients, whereas MND cystic anomalies did not regress spontaneously.

DISCUSSION

When MND tubulocystic structures persist along with renal agenesis or MCDK, most arise from ureteric bud structures in an orthotopic position as a ureterocele with or without a blind-ending ureter-like structure. Less commonly, ureteric bud structures insert ectopically into the urogenital tract, or tubulocystic structures arising from the remainder of the MND occur. Embryogenesis of other urogenital structures may also be abnormal, and conditions such as Zinner syndrome and obstructed hemivagina and ipsilateral renal agenesis syndrome should be considered.

CONCLUSIONS

Complications are uncommon, and surgical intervention should be limited to symptomatic patients. Remnants of metanephric blastema may involute, but MND remnants persist.

Anomalies of the genitourinary tract in children with 22q11.2 deletion syndrome

The 22q11.2 deletion syndrome (22q11.2DS) involves multiple organ systems with variable phenotypic expression. Genitourinary tract abnormalities have been noted to be present in up to 30-40% of patients. At our institution, an internationally recognized, comprehensive, and multidisciplinary 22q11.2DS care center has been providing care to these children. We sought to report on the incidence of genitourinary tract anomalies in this large cohort and, therefore, retrospectively reviewed all patients who underwent a complete evaluation from 1992 to March 2017. We identified all children with any genital or urinary tract anomaly. For all children with a diagnosis of hydronephrosis, the underlying etiology was determined, when possible. Overall, 1,073 of 1,267 children with 22q11.2DS underwent renal evaluations at our institution. Hundered Sixty-Two (15.1%) children had structural abnormalities of their kidneys/urinary tracts. The majority of children with hydronephrosis (63%) had isolated upper tract dilation without any additional diagnoses. Boys were significantly more likely to be diagnosed with a genital abnormality than girls (7.7 vs. 0.5%, p < 0.001). Of the 649 boys in the entire cohort, 24 (3.7%) had cryptorchidism and 24 (3.7%) had hypospadias, which was noted to be mild in all except one boy. Overall, findings of hydronephrosis, unilateral renal agenesis, and multicystic dysplastic kidney occur at higher rates than expected in the general population. Given these findings, in addition to routine physical examination, we believe that all patients with 22q11.2DS warrant screening RBUS at time of diagnosis.

Clinical features of children with multicystic dysplastic kidney

BACKGROUND

To evaluate the clinical features of patients with multicystic dysplastic kidney (MCDK).

METHODS

The medical files of children diagnosed with MCDK between January 2008 and November 2015 were retrospectively reviewed. The demographic, clinical, laboratory and radiological data were evaluated.

RESULTS

Of 128 children with MCDK enrolled in the study, 82 (64.1%) were male, and 46 (35.9%) were female (P < 0.05). MCDK were located on left and right sides in 66 (51.6%) and 62 children (48.4%), respectively (P > 0.05). Antenatal diagnosis was present in 64 patients (50%). The mean age at diagnosis was 2.8 ± 2.7 years (range, 0-8 years), and follow-up duration was 4.5 years. Fifteen patients (20.8%) had vesicoureteral reflux. Of these, four underwent endoscopic surgical correction. Other associated urological anomalies were ureteropelvic junction obstruction (n = 6), hypospadias (n = 1), and kidney stones (n = 1). On technetium-99 m dimercaptosuccinic acid scintigraphy, which was performed in all patients, no significant association between grade of reflux and presence of scarring was seen. Hypertension was diagnosed only in one child (0.8%) who required antihypertensive treatment. The prevalence of unilateral undescended testicle in children aged <1 year in the 82 male patients was 4.9%. Seventy-six patients (59.4%) developed compensatory hypertrophy in the contralateral kidney during a 1 year follow-up period. Of the total, only seven children (5.5%) had undergone nephrectomy.

CONCLUSIONS

MCDK follows a benign course with relatively few sequelae, and therefore these patients should be closely followed up and conservatively managed.

Predictors of poor neonatal outcomes in prenatally diagnosed multicystic dysplastic kidney disease

OBJECTIVE

Multicystic dysplastic kidney (MCDK) is one of the most common anomalies detected by prenatal ultrasound. Our objective was to identify factors associated with severe adverse neonatal outcomes of prenatally diagnosed MCDK STUDY DESIGN: A retrospective review of prenatally diagnosed MCDK (1 January 2009 to 30 December 2014) from a single academic center was conducted. The primary outcome was death or need for dialysis among live-born infants. Associations between prenatal characteristics and outcome were analyzed by Fisher's exact test and Mann-Whitney test.

RESULTS

A total of 53 cases of prenatally suspected MCDK were included, of which 46 cases were live-born and confirmed postnatally (38 survivors, 8 non-survivors). Prenatally diagnosed extrarenal anomalies, bilateral MCDK, contralateral renal anomalies, and anhydramnios were significantly associated with death or need for dialysis (all p < 0.0001).

CONCLUSIONS

Prenatally identified findings are associated with adverse neonatal outcome, and can guide counseling and management planning. In the absence of significant associated findings, prenatally diagnosed unilateral MCDK has a benign neonatal course.

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.

Applicability of Laparoscopic Nephrectomy in the Treatment of Multicystic Dysplastic Kidney: Sorting Out Surgical Indication

Introduction We evaluated the applicability of laparoscopic nephrectomy in the treatment of multicystic dysplastic kidney (MCDK) in children, including procedures performed by resident physicians or trainees in surgical urology. Methods We retrospectively evaluated the medical records of 20 children with MCDK who underwent laparoscopic nephrectomy over a six-year period. Data collected included gender, laterality of the affected kidney, age at the time of surgery, the largest diameter of the multicystic kidney and associated urological diagnoses, surgical, and postoperative data. All surgical procedures were performed transperitoneally. Results The mean age at the time of surgery was 46 months with a slight predominance of girls. The right side was the more affected side, and the average diameter of the affected kidney at the time of surgical excision was 5.8 cm. Other changes in the urinary tract were found in five children. The mean operative time was 133 minutes. On pathological examination, on average, the pieces measured 4.8 cm and weighed 18.1 g. There were no operative complications. The average length of hospital stay was 37.35 hours. Conclusion Laparoscopic nephrectomy was confirmed as an applicable treatment for MCDK. The technique was easy to perform, safe and efficient, even when performed by trainees in pediatric urology.

Multicystic dysplastic kidney: Assessment of the need for renal scintigraphy and the safety of conservative treatment

OBJECTIVES

To assess the need for implementing renal scintigraphy in the diagnosis of the multicystic dysplastic kidney (MCDK) and the safety of its conservative treatment.

MATERIAL AND METHODS

A retrospective study of patients with unilateral MCDK was conducted at our centre from January 2005 to August 2015. We calculated the positive predictive value (PPV) of ultrasonography, taking renal scintigraphy and pathology as the gold standard. We calculated a survival curve according to the Kaplan-Meier method to assess the annual probability of spontaneous resolution of the multicystic kidney.

RESULTS

Fifty-six patients were identified, 48 (85.7%) of whom had a prenatal diagnosis. Thirty eight (67.9%) of the patients were males, and the left side was affected in 33 (58.9%) of the patients. We observed associated urological abnormalities in 22 (39.29%) patients, with vesicoureteral reflux the most common (8, 14.29%). Seven patients (12.5%) developed renal failure. Forty-nine (87.5%) patients developed compensatory contralateral renal hypertrophy. Of the 33 patients who underwent surgery, the pathology results confirmed the MCDK diagnosis in 32. Compared with scintigraphy and pathology, the PPV of ultrasonography was 100% and 97%, respectively. The rate of spontaneous involution was 5.4% at 3 months of life, 11.3% at 2 years and 38.4% at 5 years.

CONCLUSIONS

In our experience, the conservative treatment of MCDK, until at least 5 years of age, is safe. Our data suggest that performing scintigraphy is not required for these patients, which means lower radiation exposure, as well as financial savings.