Management and etiology of the unilateral multicystic dysplastic kidney: a review

Multicystic renal dysplasia, a histomorphological spectrum: Seven years experience from a tertiary care hospital

OBJECTIVES

Multicystic dysplastic kidney (MCDK) is defined as the presence of multiple noncommunicating cysts of various sizes, detected sonographically, without evidence of functioning renal parenchyma on dimercaptosuccinic acid renal scan. It has an incidence of 1:4000 live births. They are more commonly diagnosed in boys, usually on the left side, but may also be bilateral. There is the presence of primitive ducts surrounded by fibromuscular connective tissue. These are because of the disturbed connection of the ureteric bud with renal blastema and abnormal division at the stage of metanephros, resulting in an abnormal metanephros differentiation.

MATERIALS AND METHODS

Thirty cases of MCDK were included to study their histomorphology along with their clinical features. Cases were retrieved from the last seven years (2015-2021) from the Department of Pathology, Maulana Azad Medical College.

RESULT

Age ranged from 10 days to 18 years. The cases were between 1 years and 5 years of age. Six out of 30 cases (20%) were infants with three of them being neonates. Twenty-one cases were males. All the cases had unilateral kidney involvement with the left kidney being involved in 20 out of 30 cases. Twenty-eight cases underwent nephrectomy in view of small contracted nonfunctional kidneys with one of them being horseshoe shaped. Five cases had associated hydronephrosis (two ipsilateral and three bilateral). One case had Hirshprung's disease, four had anorectal malformation, two had posterior urethral valves with vesicourethral reflux, one had duplex moiety, and one had undescended testes. On histopathological examination, all of them showed the presence of immature disorganized tubules surrounded by a collarette of immature mesenchymal stroma. One of the cases showed osteoid formation and four had areas of immature cartilage. Normal kidney parenchyma was seen at the periphery in four cases.

CONCLUSION

This series has been presented to highlight the various histomorphological features of MCDK. MCDK can be managed conservatively in most of cases due to autoinvolution and, hence, needs to be differentiated from other close differentials like polycystic kidney disease, cystic nephroma, and cystic partially differentiated nephroblastoma in order to avoid unnecessary surgical intervention.

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.

Cystic kidney diseases in children

Cystic kidney disease comprises a broad group of heterogeneous diseases, which differ greatly in age at onset, disease manifestation, systemic involvement, disease progression, and long-term prognosis. As our understanding of these diseases continues to evolve and new treatment strategies continue to emerge, correctly differentiating and diagnosing these diseases becomes increasingly important. In this review, we aim to highlight the key features of the most relevant cystic kidney diseases, underscore important diagnostic characteristics of each disease, and present specific management options if applicable.

Multicystic Dysplastic Kidney Disease: An In-Utero Diagnosis

Multicystic dysplastic kidney (MCDK) is a congenital cystic kidney disease that can be incidentally seen during the antenatal ultrasound. The condition is most commonly asymptomatic. The clinical presentation is usually characterized by multiple small cysts or a single dominating cyst in the fetal kidney depending on the type of MCDK. Most cases undergo spontaneous involution, and complications like hypertension, infection, and malignancy are rare. We present the case of a young Primigravida who was diagnosed to have a fetus with unilateral MCDK in the second trimester and further followed up later in pregnancy as well as four months postnatally. The pregnancy was unremarkable, but for the diagnosis of MCDK in the second trimester; the infant was doing well at the four-month follow-up. Pre-natal ultrasound and MRI are able to diagnose MCDK reliably. Conservative management and follow-up is currently the most common protocol used to manage MCDK.

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.

CAKUT: A Pediatric and Evolutionary Perspective on the Leading Cause of CKD in Childhood

The global prevalence of chronic kidney disease (CKD) is increasing rapidly, due to increasing environmental stressors through the life cycle. Congenital anomalies of kidney and urinary tract (CAKUT) account for most CKD in children, with a spectrum that can lead to kidney failure from early postnatal to late adult life. A stressed fetal environment can impair nephrogenesis, now recognized as a significant risk factor for the development of adult CKD. Congenital urinary tract obstruction is the leading cause of CKD due to CAKUT and can itself impair nephrogenesis as well as contribute to progressive nephron injury. Early diagnosis by ultrasonography in fetal life by an obstetrician/perinatologist can provide important information for guiding prognosis and future management. This review focuses on the critical role played by the pediatrician in providing timely evaluation and management of the patient from the moment of birth to the transfer to adult care. In addition to genetic factors, vulnerability of the kidney to CKD is a consequence of evolved modulation of nephron number in response to maternal signaling as well as to susceptibility of the nephron to hypoxic and oxidative injury. Future advances in the management of CAKUT will depend on improved biomarkers and imaging techniques.

A case of right hypodysplastic kidney and ectopic ureter associated with bicornuate uterus in a prepubertal girl

Congenital anomalies of the kidney and urinary tract (CAKUT) are frequently associated with Mullerian anomalies. This can be explained by the fact that Mullerian duct elongation depends on the preformed Wolffian duct during embryogenesis. While CAKUT such as unilateral renal agenesis and multicystic dysplastic kidney are commonly identified prenatally by routine ultrasound, the diagnosis of Mullerian anomalies is often delayed, increasing the risk of complications such as endometriosis or pelvic inflammatory disease. Herein, we report a case of a premenarchal girl who had initially been diagnosed with right multicystic dysplastic kidney. She presented with continuous urinary incontinence at 4 years old and further evaluation by contrast-enhanced computed tomography, cystoscopy, colposcopy, ureterography, and hysterosalpingography led to the final diagnosis of right hypodysplastic kidney and ectopic ureter associated with bicornuate uterus. A strong family history of uterine malformations prompted the examination of the uterus. Genetic testing was suggested but the family declined. She is planned to be referred to a gynecologist at puberty for further assessment. The recognition and screening rate of concurrent Mullerian anomalies in CAKUT patients varies between institutions. Screening for Mullerian anomalies in prediagnosed CAKUT girls may enable to provide timely counseling and to prevent gynecological complications.

Zinner syndrome in children: clinical presentation, imaging findings, diagnosis, and outcome

BACKGROUND

Zinner syndrome (ZS), the association of congenital seminal vesicle cyst (SVC) and ipsilateral kidney anomalies, is rarely diagnosed in childhood. This study aimed to assess presentation, imaging findings, management, and outcome of pediatric ZS.

METHODS

Sixteen children with ZS were diagnosed and managed at our hospital from 2003 to 2021. We reviewed the medical records to collect data on initial symptoms, results of imaging studies, complications, operation, and follow-up.

RESULTS

Ultrasound was used in all 16 cases as initial diagnostic tool. Fourteen patients were asymptomatic at diagnosis: these were transferred from obstetricians or pediatricians for evaluation of the prenatally or postnatally detected ultrasonic kidney anomalies. SVCs were incidentally noted on ultrasonography. The other two cases initially presented with urinary tract infection (UTI). Kidney anomalies included multicystic dysplastic kidney in 3 and kidney agenesis in 13 patients. Eleven (68.7%) patients had ipsilateral ectopic ureters entering SVC. Four (36.4%) patients had a reflux from urethra into SVC (urethro-cystic reflux) on voiding cystourethrography. Ten (62.5%) patients remained asymptomatic over a mean of 58 months (range, 7-216 months), two patients developed lower urinary tract dysfunction, and five patients had UTIs. Two boys needed SVC removal, and SVC had disappeared in two patients after 2.5-4 years of follow-up.

CONCLUSIONS

Unilateral kidney hypodysplasia with ectopic ureter inserting into the ipsilateral SVC is a characteristic sign for diagnosis of ZS. In our case series, ZS was mainly asymptomatic. Urethro-cystic reflux was associated with UTIs in young infants. SVC removal was rarely required. A higher resolution version of the Graphical abstract is available as Supplementary information.

Factors influencing the development of Multicystic Dysplastic Kidney (MCDK) following urinary tract obstruction in the fetal lamb

BACKGROUND

Creating obstructive uropathy (OU) during glomerulogenesis in the fetal lamb results in multicystic dysplastic kidney (MCDK) at term. We explored this using immunohistochemical techniques.

METHOD

OU was created in fetal lambs at 60-day gestation, ligating the urethra and urachus. The kidneys of MCDK lambs, 60-day gestation fetal lambs, full-term lamb (145 days), term sham-operated lambs, and adult ewes were evaluated by HE staining, and immunohistochemistry with paired box genes 2 (PAX2) and CD10.

RESULTS

Multiple cysts were found in the MCDK model. CD10 was expressed in proximal tubular epithelial cells, glomerular epithelial cells, and medullary stromal cells in the kidneys of 60-day gestation fetal lambs and full-term lambs and adult ewes. PAX2 expression was found in ureteric buds, C- and S-shaped bodies, epithelial cells of collecting ducts, and Bowman's capsule of fetal kidneys at 60-day gestation, but only in the collecting ducts of full-term fetal lambs and adult ewes. Both CD10 and PAX2 were expressed in the cystic epithelial cells of the MCDK model.

DISCUSSION

PAX2 expression in cystic epithelial cells suggests that cyst formation is associated with disturbed down-regulation of PAX2 in the nephrogenic zone epithelial cells during the renal development in the OU model.

Sonography in Childhood and Adolescence for General Radiologists - More Possibilities Than Expected

Sonography is the most common imaging modality in childhood and adolescence. The rapid availability, absence of X-rays, bedside applicability, e. g., in intensive care units, the lack of need for sedation, and last but not least the very good ultrasound conditions in the vast majority of cases are the main advantages of sonography. Due to the spectrum of patients, from premature infants to adolescents, a great variety of questions arise for the examiner. This requires knowledge of the various disease patterns in the different age groups. Proper handling of the young patients as well as their parents is essential in order to make the examination conditions as optimal as possible. Due to the smaller body size compared to adults, sonographic examinations of the abdomen and thorax in children and adolescents are usually possible with very good image quality. In the majority of cases, a definitive diagnosis is made by sonography without additional cross-sectional imaging, which is more common in adults. Due to the acoustic windows provided by the still open fontanelles, excellent image quality of the central nervous system is usually possible in the first year of life. In most cases, complex MRI examinations are not necessary. Due to the partly still missing ossification of the bony structures, further acoustic windows are available, which allow an examination of, e. g., the spinal canal. Ultrasound also plays a major role in the examination of soft tissues and the musculoskeletal system in childhood and adolescence, not only in hip ultrasound. The aim of this article is to show this very broad spectrum for colleagues working predominantly in adult radiology, to highlight some representative examples and to present the respective clinical features in childhood and adolescence. KEY POINTS::   · Ultrasound is the most important initial imaging modality in children and adolescents.. · Often, no further cross-sectional imaging is necessary.. · The most important area of application is the abdomen and pelvis.. · Furthermore, there are additional special applications such as CNS in neonates and infants, thorax, musculoskeletal system.. CITATION FORMAT: · Schaal MC, Moritz JD, Mentzel H et al. Sonography in Childhood and Adolescence for General Radiologists - More Possibilities Than Expected.... Fortschr Röntgenstr 2021; DOI: 10.1055/a-1681-2136.

Neonatal multicystic dysplastic kidney with mass effect: A systematic review

INTRODUCTION

Multicystic Dysplastic Kidney (MCDK) is a common cause of palpable abdominal mass in a neonate, yet reports are few of resultant life-threatening extrinsic compression. This systematic review is the first to review all known neonatal MCDK cases complicated by external compression due to mass effect. Our aim is to foster communication about these unusual cases to inform management of future comparable cases.

METHODS

This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Medical Subject Headings (MeSH) were used to search PubMed through June 8, 2021 as follows: ((((Polycystic Kidney Diseases/complications [MeSH Terms]) OR (Multicystic Dysplastic Kidney/complications [MeSH Terms])) AND (Humans [MeSH Terms]) AND (Infant, Newborn [MeSH Terms]) AND (Case Reports [Publication Type]) AND (("multicystic dysplastic kidney") OR ("multicystic kidney")))) OR ((unusual respiratory distress in newborn [Title]) AND (kidney)) OR (large MCDK). Resulting papers were screened and included if they reported neonatal MCDK complicated by external compression by mass effect. Excluded papers lacked an MCDK diagnosis, a neonatal patient, or clear indication of mass effect. Salient data was extracted from each case for comparison.

RESULTS

Of 51 papers screened, seven met inclusion criteria, presenting eight neonatal MCDK patients exhibiting varied combinations of symptoms secondary to external compression, including respiratory distress, gastrointestinal obstruction, and contralateral ureteral obstruction. All eight cases, ultimately managed with neonatal nephrectomy, had positive outcomes. Unreported and undiagnosed cases are not included in this review, making it susceptible to publication bias.

CONCLUSIONS

Large neonatal MCDK is typically managed conservatively, however it can be complicated by external compression due to mass effect. In this scenario, nephrectomy is a reasonable and definitive treatment. Less invasive management options may exist, e.g., aspiration with sclerotherapy. Communication about exceptional cases like these should be encouraged even when outcomes are poor.

Outcomes of solitary functioning kidneys-renal agenesis is different than multicystic dysplastic kidney disease

BACKGROUND

Multicystic dysplastic kidney (MCDK) disease and unilateral renal agenesis (URA) are well-known causes of a solitary functioning kidney (SFK) and are associated with long-term kidney injury. The aims of this study were to characterize the natural history of SFK at our center, define the risk factors associated with chronic kidney injury, and identify distinguishing features between URA and MCDK that predict outcome.

METHODS

This was a retrospective cohort study of 230 SFK patients. We compared MCDK (n=160) and URA (n=70) according to clinical features at diagnosis and kidney outcomes over follow-up. Univariate and multivariate binary regression analysis was used to determine independent risk factors for chronic kidney injury, defined as the composite outcome of hypertension, proteinuria, or chronic kidney disease (eGFR <60 mL/min/1.73m²).

RESULTS

URA had a higher prevalence of comorbid genetic syndromes (15 vs. 6%, p=0.04), non-renal anomalies (39 vs. 11%, p<0.001), and congenital anomalies of the kidney and urinary tract (CAKUT) (51 vs. 26%, p<0.001) than MCDK. Over follow-up, URA experienced more hypertension (19 vs. 3%, p=0.002), proteinuria (12 vs. 3%, p=0.03), and the composite outcome (19 vs. 6%, p=0.003) than MCDK. Independent risk factors for chronic kidney injury included CAKUT (OR 5.01, p=0.002) and URA (OR 2.71, p=0.04).

CONCLUSIONS

In our population, URA was more likely to have associated syndromes or anomalies, and to have worse outcomes over time than MCDK. URA diagnosis was an independent risk factor for chronic kidney injury. Our results will be used to develop a standardized clinical pathway for SFK management. A higher resolution version of the Graphical abstract is available as Supplementary information.

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.

Reducing Unnecessary Imaging in Children With Multicystic Dysplastic Kidney or Solitary Kidney

BACKGROUND AND OBJECTIVES

Children with isolated unilateral multicystic dysplastic kidney (MCDK) or congenital solitary kidney (CSK) undergo serial renal ultrasonography with variable frequency until they are transitioned to adult care. A growing body of literature suggests the value of frequent ultrasonography in this population is limited, providing no benefit to overall outcomes. Despite emerging evidence, ultrasound remains overused, resulting in avoidable health care expenditures and unnecessary use of resources. With our initiative, we aimed to improve quality of care by reducing avoidable ultrasounds in these children.

METHODS

This was a single-center, prospective, interrupted time series of children <18 years with ultrasound-confirmed isolated unilateral MCDK or CSK in the outpatient nephrology clinic to evaluate the effect of a decision-making algorithm on the proportion of children receiving an avoidable ultrasound. An algorithm depicting a consensus, evidence-based protocol for managing pediatric MCDK or CSK was refined through content expert feedback and usability testing to standardize frequency of ultrasonography. Ultrasounds were deemed necessary after birth, at 6 months, and at 2, 5, 10, and 15 years. Differences pre- and postintervention were determined by using a U chart and t and F tests for significance.

RESULTS

The algorithm resulted in a 47% reduction (P < .001) in the proportion of avoidable ultrasounds ordered in children with MCDK and CSK. This reduction was sustainable over a 6-month period and would result in at least $46 000 annual savings.

CONCLUSIONS

Introduction of a clinical decision-making algorithm was associated with a reduction in avoidable ultrasound testing. Improving adherence across providers may allow for an even more pronounced reduction.

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.

Prenatal diagnosis and outcome of unilateral multicystic kidney

We reviewed the records of 144 patients. The mean gestational age at first US diagnosis was 27.5 ± 4.3 weeks. An anomaly of the contralateral kidney was detected in 25% of cases. An extrarenal anomaly was detected in 13.8%. Karyotype analysis was performed in 16.6% of cases and revealed trisomy 18 in 2 cases with extrarenal defects. Karyotype analysis was normal in all the patients who had isolated multicystic dysplastic kidney (MCDK). The diagnostic accuracy of prenatal ultrasound was 92.2%. Contralateral kidney anomaly was detected 33.9% of patients, and half of these were vesicoureteral reflux. Antihypertensive therapy was required in 2.6% of cases. Nephrectomy was performed in 8%, and partial or total involution of MCDK was achieved in 33.9% of patients. MCDK can be accurately diagnosed by prenatal sonography, and prognosis depends on extrarenal and contralateral renal abnormalities. In isolated cases, require of surgery is rare, and serial follow-up is suggested to determine involution.Impact statementWhat is already known on this subject? Multicystic dysplastic kidney (MCDK) is one of the most renal anomalies and is associated with numerous renal and extrarenal abnormalities. It can lead to severe consequences in the neonatal period.What do the results of this study add? The accuracy of prenatal ultrasonography is excellent for detecting MCDK. In isolated unilateral cases, chromosomal aberrations are low, and the majority of them involute spontaneously. A periodic follow-up of the contralateral kidney is mandatory due to an increased risk of an anomaly. Genital anomaly risk is increased in males.What are the implications of these findings for clinical practice and/or further research? Detailed evaluation and follow-up of the contralateral kidney are crucial for counselling in isolated cases. Karyotype analysis in isolated unilateral MCDK is debateable. Postnatal prognosis is encountering, and the majority of patients have no requirement of surgery.

Multicystic Dysplastic Kidney With Mass Effect in a Neonate Treated With Nephrectomy: Case Report

Multicystic Dysplastic Kidney is a developmental disease that results in a lobulated kidney of noncommunicating cysts and abnormal parenchymal tissue. Dysplastic kidneys are usually benign and often involute over time with conservative management. The second most common cause of palpable abdominal mass in a neonate, Multicystic Dysplastic Kidney can cause respiratory distress secondary to extrinsic compression. However, such cases are sparse. Here we present the case of an otherwise healthy term newborn with an exceptionally large MCDK requiring CPAP support and intubation. His respiratory distress improved immediately after nephrectomy. Communication about cases like this will inform management of future comparable cases.

Renal growth slope in children with congenital and acquired solitary functioning kidneys

Purpose

This study aimed to analyze the renal growth slope in children with congenital and acquired solitary functioning kidneys.

Methods

This retrospective study included all renal ultrasonography examinations performed in children in the agenesis, multicystic dysplastic kidney (MCDK), or nephrectomy group between September 2002 and February 2019. We reviewed the images and recorded the contralateral kidney size only when there was no focal lesion. Linear mixed model or piecewise linear mixed model analyses with a time point of 24 months of age were performed.

Results

There were 132 patients, including 26 patients in the agenesis group, 35 in the MCDK group, and 71 in the nephrectomy group. The nephrectomy group showed the largest baseline kidney size (7.4 cm vs. 5.3 cm in the agenesis group [P<0.001] and 5.2 cm in the MCDK group [P<0.001]) and the smallest overall growth slope (0.04 cm/mo vs. 0.06 cm/mo in the agenesis group [P=0.004] and 0.07 cm/mo in the MCDK group [P<0.001]). However, considering the time point of 24 months for reaching adult renal function, there were significant changes in slope, from 0.1 cm/mo before 24 months of age to 0.03 cm/mo after 24 months of age in all three groups (P<0.001), without a significant difference among the groups.

Conclusion

Significant changes were found in the renal growth slope before and after 24 months of age, with no significant difference between congenital and acquired solitary functioning kidneys.

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.

Role of transcription factor hepatocyte nuclear factor-1β in polycystic kidney disease

Hepatocyte nuclear factor-1β (HNF-1β) is a DNA-binding transcription factor that is essential for normal kidney development. Mutations of HNF1B in humans produce cystic kidney diseases, including renal cysts and diabetes, multicystic dysplastic kidneys, glomerulocystic kidney disease, and autosomal dominant tubulointerstitial kidney disease. Expression of HNF1B is reduced in cystic kidneys from humans with ADPKD, and HNF1B has been identified as a modifier gene in PKD. Genome-wide analysis of chromatin binding has revealed that HNF-1β directly regulates the expression of known PKD genes, such as PKHD1 and PKD2, as well as genes involved in PKD pathogenesis, including cAMP-dependent signaling, renal fibrosis, and Wnt signaling. In addition, a role of HNF-1β in regulating the expression of noncoding RNAs (microRNAs and long noncoding RNAs) has been identified. These findings indicate that HNF-1β regulates a transcriptional and post-transcriptional network that plays a central role in renal cystogenesis.

Trends in surgical management of multicystic dysplastic kidney at USA children's hospitals

INTRODUCTION AND OBJECTIVE

Multicystic dysplastic kidney (MCDK) is a congenital renal cystic disease often incidentally diagnosed in children. Historically, children with MCDK underwent early nephrectomy because of concerns for the development of hypertension or malignancy. Over the last decade, management recommendations have not supported routine early surgical removal of MCDK. The study authors sought to determine the current trends in the use of nephrectomy for MCDK in US children's hospitals because national practice patterns have not been investigated.

METHODS

A population-based retrospective cohort study using the Pediatric Health Information System (PHIS) was conducted. The study population was comprised of patients aged 0-18 years with a diagnosis of MCDK (International Classification of Diseases-9th revision, code 753.19) admitted to the inpatient department of the study hospital between January 2006 and September 2015. Patients with additional renal anomalies including polycystic kidney, medullary cystic kidney, and medullary sponge kidney were excluded, as were patients treated in a hospital that did not contribute data to the PHIS continuously throughout the study period. Trends in the annual proportion of nephrectomies performed were analyzed among admissions in the study population, along with patient clinical and demographic information.

RESULTS

A total of 3792 MCDK admissions, in 34 hospitals, were included in the study. Overall, 569 nephrectomies were performed during the study period. The proportion of nephrectomy decreased annually by 9.2% on average, from 22.1% in 2006 to 7.3% in the first 3 quarters of 2015. No significant trends were observed in the annual number of overall MCDK admissions or patient age at procedure among patients who had a nephrectomy. Among nephrectomies, 84.2% were open and 15.8% were minimally invasive procedures (laparoscopic non-robotic, 10% and robotic, 5.8%). The proportion of minimally invasive nephrectomies increased annually by 13.7%, from 8% in 2006 to 29% in 2015.

DISCUSSION

Trends in the use of nephrectomy for MCDK at a national level have not been previously reported. This study is limited by the use of inpatient discharge data, which did not allow estimating the true rate of nephrectomy in patients born with MCDK.

CONCLUSIONS

During the study period, there has been a decrease in the use of nephrectomy for MCDK in pediatric hospitals, along with a concurrent increase in utilization of minimally invasive techniques to perform nephrectomies. These results suggest that in general, urologists at freestanding children's hospitals are heeding recommendations for observation and against routine early surgical removal of these kidneys; although trends in the use of nephrectomy varied between hospitals, there is room for continued improvement in following these recommendations.

Congenital Anomalies of the Kidney and Urinary Tract: A Clinical Review

Purpose of review

This review highlights the most common congenital anomalies of the kidney and urinary tract (CAKUT) that are encountered in pediatric practices. CAKUT are the most common cause of prenatally diagnosed developmental malformations and encompass a spectrum of disorders impacting lower urinary tract development as well as kidney development and function. In pediatric and adolescent populations, developmental abnormalities are the leading cause of end-stage kidney disease. The goal of this review is to provide pediatric providers a framework for appropriate clinical management as well as highlight when referral to subspecialty care is needed.

Recent findings

While the exact etiologies of CAKUT are not completely defined, new evidence demonstrates that genetic and molecular changes impact embryonic kidney and urinary tract development. As a result, phenotypes and clinical outcomes may be affected.

Summary

Because pediatric providers provide front-line care to children and adolescents with developmental kidney and urinary tract anomalies, updated knowledge of CAKUT pathogenesis, embryology, clinical management, and patient outcomes is needed. This manuscript reviews CAKUT etiologies and essential diagnostic, prognostic, and management strategies.

Knowledge of vesicoureteral reflux obtained by screening voiding cystourethrogram in children with multicystic dysplastic kidney does not change patient management or prevent febrile urinary tract infection

INTRODUCTION

While children with multicystic dysplastic kidneys (MCDK) are predisposed to contralateral kidney (CK) vesicoureteral reflux (VUR), it is unknown if this results in an increased risk of urinary tract infection (UTI). The authors hypothesized that knowledge of VUR via voiding cystourethrogram (VCUG) would enable altered practices to prevent UTI and thus reduce the number of febrile urinary tract infections (fUTIs).

METHODS

The authors performed a retrospective chart review of all patients at their institution of multiple providers caring for patients with a diagnosis of MCDK from 1/1/07 to 7/14/17. Patients were evaluated for age, sex, circumcision status, race, imaging results on renal ultrasound (RUS) and/or VCUG, occurrence of fUTI, and prophylactic antibiotic (ppx) use.

RESULTS

One hundred sixty-five patients were identified; 70% of patients were diagnosed with MCDK on prenatal imaging. Seventy-seven (47%) patients had a screening VCUG after diagnosis of MCDK. Eighteen patients with VCUG had VUR with 13 (17%) having VUR in the CK. Only children undergoing VCUG were placed on ppx with no difference in the use of ppx in patients with and without dilating VUR (45% vs 43%; p = 0.91). Overall, 11 patients experienced a fUTI. There was no significant difference in fUTI between those children who underwent VCUG compared with those who did not (10% vs 3%; p = 0.07). Use of ppx and presence of CK renal anomaly on RUS had no impact on incidence of subsequent fUTI.

CONCLUSION

Knowledge of VUR based on VCUG results did not reduce the rate of fUTI or predict ppx use in the practice of multiple providers. The authors feel this confirms the low utility of VCUG in the practical management of otherwise healthy children with MCDK.

Lump type crossed fused renal ectopia with bilateral vesicoureteral reflux: A case report

BACKGROUND

Crossed fused renal ectopia is a rare congenital anomaly of the ascent of the kidney. This anomaly may be observed as a solitary kidney during initial evaluation. A solitary kidney must be evaluated for associated anomalies such as duplication, horseshoe kidney, or crossed renal ectopia.

CASE SUMMARY

An anomaly was observed in a 9-mo-old male child who was subsequently diagnosed with crossed fused renal ectopia and vesicoureteral reflux (VUR). In this condition, recurrent febrile urinary tract infection can be a serious problem, and can easily cause renal damage due to relatively short ureters and high pressure in the kidney.

CONCLUSION

To prevent urosepsis and preserve renal function, early diagnosis and proper management including surgical correction should be considered for the management of renal ectopia with VUR.

A meta-analysis of the incidence and fate of contralateral vesicoureteral reflux in unilateral multicystic dysplastic kidney

INTRODUCTION

Multicystic dysplastic kidney (MCDK) is the most common type of renal cystic disease. It is associated with urinary tract abnormalities in the contralateral kidney in up to 30% of cases, most commonly vesicoureteral reflux (VUR).

OBJECTIVES

The objective of this study was to describe the incidence and selected issues in management and evolution for each VUR grade in the contralateral kidney of patients with unilateral MCDK, in order to strengthen the scientific basis regarding the need for voiding cystourethrography (VCUG) screening.

METHODS

A comprehensive search of standard and gray literature was performed. Full-text screening, data abstraction, and quality appraisal were conducted in duplicates. Included studies reported a primary diagnosis of unilateral MCDK with contralateral VUR determined by VCUG. Articles had to include a distribution of VUR grade to meet the eligibility criteria.

RESULTS

From 698 retrieved articles, 37 studies enrolling 2057 patients were analyzed. Of the patients, 80% were male; 50% had left unilateral MCDK; and 87% were diagnosed prenatally. A total of 1800 patients had VCUG, of whom 303 had VUR (weighted proportion: 17%; 95% confidence interval [CI]: 14-20%). Weighted proportions of VUR were 9%, 7%, and 17% for grades I-II, III-V, and I-V, respectively. Of the patients, 99% (95% CI: 97-100%) were on continuous antibiotic prophylaxis (CAP) and 18% (95% CI: 8-37%) had urinary tract infections (UTIs), with a higher rate of UTIs (23% vs 10%) in patients with dilating (grades III-V) VUR, over a mean follow-up of 40 months. In patients with dilating VUR, reflux resolved or downgraded to grade I in 52% (95% CI: 37-67%) of patients, and 32% (95% CI: 19-49%) had surgical correction of VUR.

CONCLUSIONS

Among patients with unilateral MCDK, 17% have VUR in the contralateral kidney, 41% of which is dilating VUR. Of the cases with dilating VUR, half will resolve or downgrade to grade I during follow-up; 23% will develop a UTI despite CAP; and one-third will undergo ureteral re-implantation. While many physicians may thus choose to forego routine VCUG screening of the single functional kidney, shared decision-making with the patient's caregivers is currently recommended, where the risks and benefits of the different approaches can be discussed. The data from this analysis can help inform the discussions.

Necessity of performing voiding cystourethrography for children with unilateral multicystic dysplastic kidney

BACKGROUND

The purpose of this study was to resolve the clinical question as to whether all patients with unilateral multicystic dysplastic kidney (MCDK) should receive voiding cystourethrography (VCUG).

METHODS

This is a retrospective study using cross-sectional analysis. Seventy-five children with unilateral MCDK were enrolled, excluding patients with other genetic or chromosome abnormalities, spinal cord diseases, or anal atresia. We reviewed their records from medical charts and calculated risk factors for abnormal VCUG using multivariate logistic regression analysis.

RESULTS

Abnormal VCUG findings were present in 24 of 75 patients (32.0%), specifically, vesicoureteral reflux (VUR) in 8 (10.6%), including high-grade VUR in 2 (2.7%), and only lower urinary tract or bladder disease in 16 (21.3%). In multivariate analysis, only abnormal findings by ultrasonography was an independent risk factor for abnormal VCUG findings with statistical significance in multivariate analysis (OR 6.57; 95% CI 1.99-26.26; P = 0.002). When we excluded five patients who showed similar findings by ultrasonography and VCUG, abnormal findings by ultrasonography were again calculated as an independent risk factor (OR 4.44; 95% CI 1.26-28.42; P = 0.02). Sensitivity, specificity, positive predictive value, and negative predictive value of abnormal findings by ultrasonography to predict urologic anomalies by VCUG in these children were 83%, 59%, 49%, and 88%, respectively. Two children required a third ultrasonography to detect abnormal findings.

CONCLUSIONS

We can select, using only abnormal findings by ultrasonography, children with unilateral MCDK who should undergo VCUG. We would also like to emphasize that ultrasonography should be performed repeatedly to detect congenital anomalies of the urinary tract.

Congenital solitary kidney size at birth could predict reduced eGFR levels later in life

OBJECTIVES

To evaluate the impact of congenital solitary functioning kidney (CSFK) length, measured early in life, on the eGFR levels during the follow-up.

STUDY DESIGN

We retrospectively selected 162 CSFK patients undergoing, within 60 days of life, renal length (RL) measurement by ultrasound. We divided the population in: Group 1 = RL ≥ 2 standard deviation score (SDS). Group 2 = RL < 2 SDS and showing RL ≥ 2 SDS during the follow-up. Group 3 = RL < 2 SDS and showing RL < 2 SDS during the follow-up.

PRIMARY OUTCOME

development of eGFR below the range of normality.

RESULTS

The median follow-up period of the overall population was 6.2 years (range 2-21.5 years). The cumulative proportion of patients free of primary outcome at 15 years of age was 96.4% in group 1, 64.6% in group 2, and 45.6% in group 3 (p = 0.03). The RL > 2 SDS within 60 days of life was a significant protective factor (hazard ratio = 0.13; 95% C.I. 0.02-0.97) against development of primary outcome.

CONCLUSION

RL ≥ 2 SDS within 60 days of life could identify a population of CSFK with reduced risk of presenting reduced eGFR levels later in life.

Developmental pathology of congenital kidney and urinary tract anomalies

Congenital anomalies of the kidneys or lower urinary tract (CAKUT) are the most common causes of renal failure in children and account for 25% of end-stage renal disease in adults. The spectrum of anomalies includes renal agenesis; hypoplasia; dysplasia; supernumerary, ectopic or fused kidneys; duplication; ureteropelvic junction obstruction; primary megaureter or ureterovesical junction obstruction; vesicoureteral reflux; ureterocele; and posterior urethral valves. CAKUT originates from developmental defects and can occur in isolation or as part of other syndromes. In recent decades, along with better understanding of the pathological features of the human congenital urinary tract defects, researchers using animal models have provided valuable insights into the pathogenesis of these diseases. However, the genetic causes and etiology of many CAKUT cases remain unknown, presenting challenges in finding effective treatment. Here we provide an overview of the critical steps of normal development of the urinary system, followed by a description of the pathological features of major types of CAKUT with respect to developmental mechanisms of their etiology.

Name That Nephrogram: Asymmetric Renal Enhancement in the Acute Care Setting

Disorders of the kidney and urinary collecting system are common encountered in the acute care setting. Computed tomography has progressively replaced intravenous pyelography for the evaluation of most urinary tract pathology including acute flank pain, suspected malignancy, congenital abnormalities, anatomical variants, and inflammatory/vascular conditions through evaluation of the "nephrogram" produced by intravenous contrast material filtering through the kidneys. In this review, we describe the most common types of abnormal nephrograms seen on renal computed tomography, and highlight the salient features and conditions associated with them, in addition to a pictorial review with specific and interesting related cases. The types of abnormal nephrograms reviewed are absent, unilateral delayed, striated, spotted, and persistent.

Outcomes of prenatally diagnosed solitary functioning kidney during early life

OBJECTIVE

To evaluate outcomes of congenital solitary functioning kidney (SFK) in early childhood.

STUDY DESIGN

A retrospective study of 32 children diagnosed in utero with SFK owing to unilateral renal agenesis or multicystic dysplastic kidney and followed for 1 to 11.5 years.

RESULTS

SFK length was in the compensatory hypertrophy range in 45% of fetal sonographic evaluations from mid-pregnancy, and in 85% on postnatal follow-up. Glomerular filtration rate was below normal range in 44.4%, 12.5% and 0% at <1 year, age 1 to 3 years and thereafter, respectively. Hyperfiltration was detected in 18.5% and 82.6% at <1 year and >3 years, respectively. Hypertension was documented in 35% at age 1 to 3 years but in none at an older age. Proteinuria was absent in all children.

CONCLUSION

Congenital SFK is apparently associated with little or no renal damage in infancy or childhood. Compensatory enlargement of the functioning kidney begins in utero and might serve as a prognostic indicator for normal renal function after birth.

Neonatal renal cystic diseases

PURPOSE

Neonatal renal cystic diseases have a great impact on the morbidity and mortality of the affected neonates and infants. A good insight into the pathophysiology, diagnosis and treatment options of various neonatal renal cystic diseases aid in early diagnosis and intervention, thereby preventing complications.

METHODS

PubMed search was done for articles on "neonatal renal cystic diseases" and relevant publications including reviews were considered for our article.

RESULTS

Both hereditary and nonhereditary causes of cystic kidney diseases can result in severe morbidity and mortality. The main diagnostic modality is ultrasound imaging and most of the neonatal renal cystic diseases are detected during prenatal ultrasound screening. Commonly encountered neonatal renal cystic diseases are autosomal dominant polycystic kidney disease, autosomal recessive polycystic kidney disease and multicystic dysplastic kidney.

CONCLUSIONS

A thorough knowledge of various renal cystic diseases can be of extreme prognostic value. Physicians should be aware of the impact of early diagnosis and intervention on the lives of those affected. Further research about treatment of these diseases is ongoing and can result in breakthrough therapies for these patients.

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.

Multicystic Dysplastic Kidney and Sonography

Multicystic dysplastic kidney is a congenital anomaly that can affect the kidneys. It is generally unilateral and is characterized by multiple noncommunicating cysts in the renal parenchyma. This disease usually results in an enlarged, nonfunctioning kidney in the neonate. Recent advances in diagnostic medical imaging, especially in sonography, have enabled earlier detection of this disease, created better management and treatment options, and resulted in improved outcomes for patients. This case study demonstrates the use of early detection with sonography and the utilization of it for follow-up care. Sonography is ranked as the imaging modality of choice for patients with a clinical condition of renal failure and has the potential for an improved outcome for patients.

Update on Multicystic Dysplastic Kidney

Multicystic dysplastic kidney (MCDK) is the most common cause of cystic disease in children. It is characterized by multiple non-communicating cysts of varying sizes with no identifiable normal renal parenchyma. The incidence ranges from 1 in 1000 to 4300 live births, and it is one of the most commonly detected anomalies on prenatal ultrasound. MCDK has been shown to follow a benign course with relatively few sequelae and therefore should be managed conservatively. Currently, the key clinical questions revolve around the detection of anomalies in the contralateral kidney and follow-up imaging. The recent literature suggests that very limited radiographic evaluation of the MCDK is needed. The use of voiding cystourethrogram or nuclear medicine renal scans should be directed by any abnormalities on renal ultrasound or the development of urinary tract infections.

CT and MR imaging for evaluation of cystic renal lesions and diseases

Cystic renal lesions are commonly encountered in abdominal imaging. Although most cystic renal lesions are benign simple cysts, complex renal cysts, infectious cystic renal disease, and multifocal cystic renal disease are also common phenomena. The Bosniak classification system provides a useful means of categorizing cystic renal lesions but places less emphasis on their underlying pathophysiology. Cystic renal diseases can be categorized as focal, multifocal, or infectious lesions. Diseases that manifest with focal lesions, such as cystic renal cell carcinoma, mixed epithelial and stromal tumor, and cystic nephroma, are often difficult to differentiate but have differing implications for follow-up after resection. Multifocal cystic renal lesions can be categorized as acquired or heritable. Acquired entities, such as glomerulocystic kidney disease, lithium-induced nephrotoxicity, acquired cystic kidney disease, multicystic dysplastic kidney, and localized cystic renal disease, often have distinct imaging and clinical features that allow definitive diagnosis. Heritable diseases, such as autosomal dominant polycystic kidney disease, von Hippel-Lindau disease, and tuberous sclerosis, are usually easily identified and have various implications for patient management. Infectious diseases have varied imaging appearances, and the possibility of infection must not be overlooked when assessing a cystic renal lesion. A thorough understanding of the spectrum of cystic renal disease will allow the radiologist to make a more specific diagnosis and provide the clinician with optimal recommendations for further diagnostic testing and follow-up imaging.

Developmental Genetics and Congenital Anomalies of the Kidney and Urinary Tract

Congenital anomalies of the kidney and urinary tract (CAKUT) are common birth defects and the leading cause of end-stage renal disease in children. There is a wide spectrum of renal abnormalities, from mild hydronephrosis to more severe cases, such as bilateral renal dysplasia. The etiology of the majority of cases of CAKUT remains unknown, but there is increasing evidence that genomic imbalance contributes to the pathogenesis of CAKUT. Advances in human and mouse genetics have contributed to increased understanding of the pathophysiology of CAKUT. Mutations in genes involved in both transcription factors and signal transduction pathways involved in renal development are associated with CAKUT. Large cohort studies suggest that copy number variants, genomic, or de novo mutations may explain up to one-third of all cases of CAKUT. One of the major challenges to the use of genetic information in the clinical setting remains the lack of strict genotype-phenotype correlation. However, identifying genetic causes of CAKUT may lead to improved diagnosis of extrarenal complications. With the advent of decreasing costs for whole genome and exome sequencing, future studies focused on genotype-phenotype correlations, gene modifiers, and animal models of gene mutations will be needed to translate genetic advances into improved clinical care.

Neonatal polycystic kidney disease

This article provides an up-to-date comprehensive review and summary on neonatal polycystic kidney disease (PKD) with emphasis on the differential diagnosis, clinical manifestations, diagnostic techniques, and potential therapeutic approaches for the major causes of neonatal PKD, namely hereditary disease, including autosomal recessive and autosomal dominant PKD and nonhereditary PKD, with particular emphasis on multicystic dysplastic kidney. A brief overview of obstructive cystic dysplasia and simple and complex cysts is also included.

Dyserythropoiesis in a child with pyruvate kinase deficiency and coexistent unilateral multicystic dysplastic kidney

Pyruvate kinase (PK) deficiency is the commonest enzyme deficiency in the glycolytic pathway leading to hemolytic anemia secondary to decreased Adenosine Triphosphate (ATP) synthesis in the red cells. synthesis. PK deficiency due to mutations in the PKLR (1q21) gene leads to highly variable clinical presentation ranging from severe fetal anemia to well compensated anemia in adults. We describe dyserythropoiesis in the bone marrow of a child with transfusion dependent anemia and unilateral multicystic dysplastic kidney (MCDK) mimicking Congenital Dyserythropoietic Anemia type I (CDA type I). Persistently low erythrocyte PK levels and double heterozygous mutations present in the PKLR gene confirmed the diagnosis of PK deficiency.

Multicystic dysplastic kidney: Impact of imaging modality selection on the initial management and prognosis

OBJECTIVE

To evaluate the impact of imaging modalities on the evaluation and prognosis of children with multicystic dysplastic kidney (MCDK) disease.

PATIENTS AND METHODS

A retrospective analysis of all children with MCDK diagnosed from 2004 until 2012 was performed. The study included 63 patients for whom all postnatal imaging modalities were available: renal bladder ultrasound (RBUS), dimercaptosuccinic acid scan (DMSA) and voiding cystourethrogram (VCUG). Cases with major congenital abnormalities or incomplete data were excluded. Abnormalities in the contralateral kidney and the fate of MCDK were also addressed.

RESULTS

At diagnosis, the average age was four-and-a-half months. The majority of cases were detected antenatally (87%). Postnatal RBUS and DMSA scans established the diagnosis of MCDK in 92% and 98% of patients, respectively. DMSA showed photopenic areas in the contralateral kidneys in 10% of patients; all of them had hydronephrosis and were confirmed to have vesicoureteral reflux (VUR). Contralateral VUR was detected in 16 patients; 63% of them had hydronephrosis. After a mean follow-up of three-and-a-half years, involution occurred in 62% of patients and the involution rate was inversely proportional to the initial size.

CONCLUSIONS

The classical appearance of MCDK on RBUS was sufficient to establish the diagnosis in most patients. DMSA scan was more accurate in confirming the diagnosis and evaluating the contralateral kidney. Selective screening for VUR in patients with contralateral hydronephrotic kidney should be considered.