Unilateral multicystic dysplastic kidney: the case for nephrectomy

Multicystic dysplastic kidney in adults: A case report of unilateral presentation in an adult sudanese female

Multicystic dysplastic kidney is a congenital anomaly typically diagnosed in infancy, rare in adults, in our case of a 25-year-old Sudanese female presented with left flank pain. Imaging showed the left kidney replaced by cysts, consistent with MCDK, and ovarian cyst. She underwent a successful open simple nephrectomy; and histopathology confirmed MCDK. Our case highlights diagnostic and management challenges of MCDK in adults. Conservative management is increasing, especially for asymptomatic patients with normal contralateral kidney function. Healthcare barriers in Sudan, including limited awareness and political unrest, complicate timely diagnosis and treatment. Multidisciplinary care and improved healthcare access are essential.

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.

The Outcome of Multicystic Dysplastic Kidney Disease Patients at King Abdulaziz Medical City in Riyadh

Background Multicystic dysplastic kidney (MCDK) is a type of kidney dysplasia consisting of many irregular, various-sized cysts divided by dysplastic renal tissue, which negatively impacts kidney function. MCDK is one of the most common renal congenital disorders seen in antenatal ultrasounds. The typical prognosis of MCDK is complete or partial involution that starts antenatally and continues postnatally. The aim of the study was to shed light on the overall outcome of patients with MCDK. Methods We retrospectively collected data on MCDK patients from 2016 until 2022 at King Abdulaziz Medical City, Ministry of National Guard Health Affairs in Saudi Arabia, Riyadh. The data included the recording of epidemiological data, radiological and laboratory reports, and the presence of urological or non-urologically associated anomalies. Results A total of 57 patients with MCDK were reviewed. Seven of them were excluded due to the diagnosis of bilateral MCDK, which was incompatible with life. Of the remaining 50 patients, the right kidney was affected in 52% of them. Most patients were diagnosed antenatally (98%). The mean duration of follow-up for the study was 48 months. Vesicoureteral reflux (VUR) was detected in 22% of the total sample. Overall, 90% of the patients underwent kidney involution. A small percentage had genitourinary anomalies (20%), while a larger percentage (48%) had extrarenal abnormalities. Conclusion Multicystic dysplastic kidney disease is relatively common in children. The prognosis is affected by the presence of genitourinary and non-genitourinary anomalies. Patients have an overall good prognosis with conservative management. Antenatal screening, diagnosis, and long-term nephrological follow-up are essential for the optimal management of patients.

Pathophysiological clinical features of an infant with hypertension secondary to multicystic dysplastic kidney: a case report

BACKGROUND

The association of hypertension with congenital renal hypoplasia has been established. We report a case of an infant who underwent nephrectomy for hypertension.

CASE PRESENTATION

Magnetic resonance imaging for the mother revealed fetal renal masses, and fetal multicystic dysplastic kidney was suspected. Following birth, the baby developed hypertension. Numerous investigations revealed that the left kidney was non-functional, and she was initiated on benazepril hydrochloride. However, because the drug response was poor, the left kidney was removed at the age of 7 months. Examination of the renal specimen revealed abrupt transition from normal to atrophic cortex with lobar atrophy and cysts. Tubular atrophy, marked abnormal blood vessels with wall thickening, gathered immature glomeruli, and parenchymal destruction were observed. Renin was partially localized in the proximal tubules and the parietal epithelium of the Bowman's capsule in the immature glomeruli. We speculated that an abnormal vascular structure and irregular renin localizations may be the cause of hypertension. Serum renin and aldosterone levels gradually reduced post-surgery, reaching normal levels on the 90th postoperative day. A long follow-up is needed due to the possibility of the child developing hypertension in the future.

CONCLUSION

This is a case of an infant with MCDK, which discusses the clinicopathological features based on the pathophysiological analysis, including renin evaluation.

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.

Evidence-based treatment of multicystic dysplastic kidney: a systematic review

OBJECTIVES

There is a lack of a standardised protocol for the investigation and non-operative management of paediatric multicystic dysplastic kidney (MCDK). Institutional protocols for non-operative management remain essentially ad hoc. The primary outcome of this systematic review is to establish the incidence of hypertension associated with an MCDK. The secondary outcome is to determine the malignancy risk associated with an MCDK. The tertiary outcome is to assess the rate of MCDK involution. Subsequent to these, an evidence-based algorithm for follow-up is described.

METHODOLOGY

A systematic review of all relevant studies published between 1968 and April 2017 was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were identified by specific inclusion and exclusion criteria, all of which included data relevant to the primary, secondary and tertiary outcomes. Hypertension was defined as systolic blood pressure greater than the 95th centile for gender, age and height centile. Subset analysis was performed for hypertension associated with an MCDK.

RESULTS

The primary outcome measure revealed a 3.2% (27/838) risk of developing hypertension associated with an MCDK. The secondary outcome measure noted a 0.07% malignancy risk (2/2820). The tertiary outcome measure established that 53.3% (1502/2820) had evidence of involution of the dysplastic kidney. A total of 44 cohort studies (2820 patients) were analysed.

CONCLUSION

Given the low risk of hypertension and malignancy, which is similar to the general population, the current conservative non-operative pathway is an appropriate management strategy. An algorithm to help support clinicians with ongoing management is proposed.

Outcome of Multi-Cystic Dysplastic Kidneys in Children

Background:

Renal cystic diseases are important causes of chronic kidney disease (CKD).

Objectives:

We report the pattern of renal cystic disease in children and evaluate the outcome of children with multicystic dysplastic kidney (MCDK).

Patients and Methods:

Retrospective study of all children with cystic kidney diseases at King Abdulaziz University hospital from 2006 to 2014.

Results:

Total of 55 children (30 males); 25 MCDK, 22 polycystic kidney diseases (PKD), 4 nephronophthises and 4 renal cysts. Consanguinity was positive in 96.2%. MCDK and simple renal cyst patients had good renal function while PKD and nephronophthisis developed renal impairment. Most MCKD were diagnosed ante-natally, 16 of them were followed up for 3.4 (1.97) year. Their last creatinine was 33.9 (13.5) umol/L. MCDK was spontaneously involuted at mean age of 2.6 (1.3) years in 56%.

Conclusions:

MCDK is the commonest cystic renal disease and diagnosed ante-natally in the majority of cases. It has a good prognosis.

Hypertension in the neonatal period

PURPOSE OF REVIEW

Continued interest in neonatal hypertension has led to generation of new data on normal blood pressure (BP) values in neonates, identification of new causes of hypertension in the neonatal period, and improved insights into therapy.

RECENT FINDINGS

Normal BP in neonates depends on a variety of factors, including gestational age, postnatal age, and birth weight, and may be influenced by other antenatal conditions. The incidence of neonatal hypertension is low, and it is most often seen in infants with concurrent conditions such as chronic lung disease (CLD) or renal disease, or in those that have undergone umbilical arterial catheterization. Although few data exist on efficacy and safety of antihypertensive medications in neonates, a wide variety of medications have been utilized in those who do require treatment. Hypertension resolves over time in most infants, although robust long-term outcome data are lacking.

SUMMARY

Our understanding of neonatal hypertension continues to evolve. Although better data are available on normal BP and the incidence of hypertension, we still need studies focused on appropriate treatment and long-term prognosis.

Hypertension in infancy: diagnosis, management and outcome

Advances in the ability to identify, evaluate, and care for infants with hypertension, coupled with advances in the practice of Neonatology, have led to an increased awareness of hypertension in modern neonatal intensive care units. This review will present updated data on blood pressure values in neonates, with a focus on the changes that occur over the first days and weeks of life in both term and preterm infants. Optimal blood pressure measurement techniques as well as the differential diagnosis of hypertension in the neonate and older infants will be discussed. Recommendations for the optimal immediate and long-term evaluation and treatment, including potential treatment parameters, will be presented. We will also review additional information on outcome that has become available over the past decade.

Multicystic dysplastic kidney: our experience in non-surgical management

INTRODUCTION

Although multicystic dysplastic kidney (MDK) is a common renal anomaly, the management of this condition remains controversial. The purpose of this study was to focus on its regression by ultrasound (US) scan for MDK managed conservatively.

MATERIALS AND METHODS

Between 1990 and 2010, 50 children with MDK were retrospectively studied. All patients were submitted to radioisotope scan to confirm the diagnosis, and a micturating cystogram to exclude other uropathies.

RESULTS

Of the 50 patients, 19 underwent nephrectomy, and the other 31 were conservatively managed with clinical and US scan follow-up. The mean follow-up time (range 6 months to 11 years) in the non-operated group was 6.2 years. Of the 31 children with nonsurgical management, 17 (54.8%) showed total involution on US scan, 7 (22.6%) showed a partial regression, and 7 (22.6%) were unchanged at the time of this study. The mean time to complete disappearance on US scan was 2.5 years (1-4 years). No children developed hypertension or tumors.

DISCUSSION

The natural history of MDK is usually benign, but patients must have long-term follow-up with US scan. In addition, many studies confirmed that the disappearance of it on a US scan does not mean a total involution of the affected kidney. We recommend a strict follow-up even when US scan shows an undetectable kidney.

Diagnostic accuracy of postnatal ultrasound screening for urinary tract abnormalities

The study was aimed at (1) the determination of the incidence of abnormalities of the urinary tract in newborn infants detected by postnatal ultrasound screening, and (2) the evaluation of the diagnostic accuracy of postnatal ultrasound screening for detecting surgical urinary tract abnormalities. The prospective study was of full-term neonates born in the University Hospital of Olomouc in 2005-2008 who underwent renal ultrasound screening after 72 h of life. Significant findings were recorded. Subsequent diagnostic and therapeutic procedures were recorded and evaluated in a group of children with detected renal pelvic dilatation (RPD). (1) A total of 6,088 newborn infants was examined. The absolute and relative RPD incidence rates (anteroposterior diameter, APD) were as follows: 5-7 mm, 146 (2.4%); 7-10 mm, 70 (1.15%); 10-15 mm, 13 (0.21%), and 15 mm or more, 5 (0.08%). Of those, 16 children were operated on for abnormalities of the urinary tract, of which nine (56%) had been detected by prenatal screening. Other findings: six cases of unilateral renal agenesis, four cases of multicystic renal dysplasia, four of renal dystopia, one of polycystic kidney disease and one of renal hypoplasia. (2) A group of 224 children with postnatally detected RPD was examined, of whom 40 (17.9%) underwent voiding cystourethrography and/or scintigraphy and 16 (7.1%) were treated surgically. The receiver operating characteristic curves were analyzed, and the areas under the curves were calculated. Postnatal renal ultrasound screening is probably a suitable test for detecting significant urinary tract abnormalities.

Fetal multicystic kidney disease: Outcome and follow up

Introduction Congenital fetal anomalies are the great problem and one of the main causes of increased perinatal mortality and morbidity. The aim of this study is to determine the outcome of prenataly detected multicystic dysplastic kidney and to point to the necessity of postnatal diagnostic procedures. Material and methods The retrospective-prospective study encompasses 38 cases of the prenatally diagnosed unilateral fetal multicystic dysplastic kidney. The associated anomalies were revealed either by autopsy findings when the pregnancy was terminated, or when the pregnancy continued, by clinical and operative findings the newborns. Results The autopsy finding revealed bilateral multicystic displastic kidney or unilateral mylticystic displastic kidney and the agenesis of the contralateral kidney. The postnatal evaluation of the newborns with unilateral multicistic disease revealed that 84.3% of them had some concomitant anomaly of the urinary tract, most of them had an anomaly of the contralateral kidney (31.4%). The surgery was performed in 73.6% of children, in 17% of children the kidney function deteriorated after the surgery. Conclusion The findings of bilateral multicystic kidney disease and unilateral multicystic kidney disease and anamnion are the indication to terminate the pregnancy. The finding of an isolated unilateral multicystic dysplastic kidney require thorough examination, both prenatally and postnatally. We propose obligatory serial prenatal ultrasound examinations, followed by postnatal ultrasound, isotope scan, and urinary cystourethography.

[Association of fetal unilateral multicystic kidney disease with other urinary tract anomalies]

BACKGROUND/AIM

Multicystic dysplastic kidney represents a disorder in the fetus development presented prenatally of postnatally, this deserving special attention due to a risk of additional anomalies in children with this disorder. The aim of this study was to determine the incidence and type of common anomalies of the urinary system in the prenatal diagnosis of unilateral multicystic dysplastic kidney, and point out the necessity of postnatal diagnostic procedures in order to evaluate the state of the urinary system.

METHODS

This retrospective-prospective study encompassed 38 cases of prenatally diagnosed unilateral fetal multicystic dysplastic kidney, presented to the Council for Fetal Anomalies from the Institute for Gynecology and Obstetrics of the Clinical Centre of Serbia and the University Children's Clinic within a three-year period. Associated anomalies were revealed by autopsy findings when pregnancy was terminated, ie resumed with clinical and operative findings of born children.

RESULTS

In every case of terminated pregnancy and death after birth the autopsy revealed additional renal or exstrarenal anomaly which were not prenataly detected. Postnatal evaluation of survived children with unilateral multicistic disease revealed that 31.4% of them have an anomaly of the contralateral kidney, 26.3% anomaly of the ipsilateral side, 13.2% anomaly of the lower portions of the urinary system and the same percent an additional extrarenal anomaly. The surgery was performed in 73.6% of children, more than half of the interventions were related to extrarenal anomaly. In 17% of children the kidney function was deteriorated after surgery.

CONCLUSION

Children suffering from unilateral multicystic dysplastic kidney have a greater chance of exhibiting an anomaly of the contralateral kidney and the urinary system in general. Therefore, they require thorough examination, both prenatally and postnatally. We propose obligatory serial professional prenatal ultrasound examinations, followed by postnatal ultrasound, isotope scan, and we especially emphasize the need for performing urinary cystouretherography, bearing in mind the high incidence of the vesicoureteral reflux of the contralateral kidney. In addition to nephrectomy, cytoscopy and colposcopy also need to be performed for the purpose of discovering possible hidden anomalies of the urogenital system.

Is the risk of hypertension an indication for prophylactic nephrectomy in patients with unilateral multicystic dysplastic kidney?

OBJECTIVE

Surgery is still proposed by some as the treatment of choice for unilateral multicystic dysplastic kidney (UMCDK) because of the potential complications of hypertension, infection and malignant change. The purpose of this study is to demonstrate that the risk of hypertension does not justify routine nephrectomy.

MATERIAL AND METHODS

We report 41 cases of UMCDK, treated between 1980 and 2001, 28 of whom were male (68%). Twenty-one patients were nephrectomized (51%). Twenty patients (49%) underwent clinical and ultrasound follow-up. Blood pressure was controlled every 3-4 months (over a period ranging from 9 months to 6 years) and an ultrasound scan was performed every 6 months during the first 2 years, and annually thereafter.

RESULTS

In the patients treated non-operatively we observed a progressive spontaneous involution of their multicystic dysplastic kidneys and the total absence of complications such as hypertension or malignancy.

CONCLUSION

It is reasonable to conservatively manage patients with UMCDK by means of repeated ultrasound examinations and blood pressure control.

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

In children, unilateral multicystic dysplastic kidney (MCDK) is one of the most frequently identified urinary tract abnormalities. A variety of proposed etiologies has been associated with the underlying pathogenesis of MCDK. These include genetic disturbances, teratogens, in utero infections, and urinary outflow tract obstruction. From 5-43% of the time, MCDK has associated genito-urinary anomalies, both structural and functional in nature. A review of the literature reveals that involution rates are reported to be 19-73%, compensatory hypertrophy of the contralateral kidney occurs from 24-81% of the time, and estimated glomerular filtration rates (GFRs) (by the Schwartz formula) range from 86-122 ml/min per 1.73 m(2) body surface area. Most authors suggest serial ultrasonography to monitor contralateral growth, routine blood pressure monitoring, and a serum creatinine monitoring algorithm. The risk of hypertension in those with MCDKs does not appear to be greater than that of the general population, and the rates of malignant transformation of MCDK are small, if at all increased, in comparison with those in the general population. If the patient develops a urinary tract infection or has abnormalities of the contralateral kidney, shown on ultrasound, a voiding cystourethrogram is recommended. Finally, the body of literature does not support the routine surgical removal of MCDKs.

Renal dysplasia and MRI: a clinician's perspective

Renal dysplasia is a common abnormality in children. The role of MRI in evaluating children with renal dysplasia is evolving. More information is clearly necessary before MRI replaces conventional imaging modalities. In order to appropriately use MRI, the radiologist must have an understanding of the clinical questions that are important in the management of children with renal dysplasia. This review provides background information on renal dysplasia for the pediatric radiologist. The focus is on unilateral disease, especially multicystic dysplastic kidneys, and bilateral dysplasia, which is the most common cause of kidney failure in children. The emphasis is on the important clinical issues, and the potential of MRI as a methodology for providing clinically useful information not otherwise available from other imaging modalities.

Long-term urological follow-up of multicystic dysplastic kidneys: Is it still indicated in 2007?

OBJECTIVE

To determine whether the current indications for the long-term urological follow-up of children with multicystic dysplastic kidneys (MCDKs) are supported by the literature.

METHODS

The membership of the Pediatric Urologists of Canada was surveyed to determine if long-term urological follow-up was being performed, and if so, for what indications. A literature search using PubMed, EMBASE and a Conference Papers Index was performed to determine whether the indications listed were supported by the literature.

RESULTS

A response rate of 72% was achieved for the survey, with most respondents following children with MCDK long-term. The main indications for long-term follow-up were the increased risk of Wilms' tumour (54%) and hypertension (32%), observation of the contralateral kidney (43%) and involution of the MCDK (36%). The literature search did not support long-term urological follow-up for any of these indications, provided unilateral MCDK was an isolated genitourinary abnormality. Although it is rare, a primary care physician could monitor for hypertension.

CONCLUSION

Long-term urological follow-up of children with "simple MCDK" is not supported by the literature, provided the diagnosis has been confirmed with a follow-up renal ultrasound at 12-24 months. Blood pressure monitoring by a primary care physician is recommended.

Does the multicystic dysplastic kidney really involute? The role of the retroperitoneoscopic approach

OBJECTIVE

To assess the role of video-assisted retroperitoneoscopy in the follow up of multicystic dysplastic kidney (MCDK) that has involuted--disappeared?--on serial renal ultrasonography (US).

PATIENTS AND METHODS

Prospectively, we performed a retroperitoneoscopy in 14 patients, nine girls and five boys, with unilateral MCDK that had involuted on serial US. MCDK was diagnosed in utero (80%) and confirmed postnatally by US and Tc99m dimercaptosuccinic acid radionuclide scan. Follow up US examinations were performed at 1 month, 5 months and 12 months in the first year of life and every 6 months from then on. US showed complete involution at a mean age of 13 months (range 5-18 months). Retroperitoneoscopy was then indicated, at a mean age of 23 months (range 8-24 months), to confirm the disappearance of the kidney dysplastic remnant.

RESULTS

Retroperitoneoscopy detected persistence of anomalous kidney tissue in 100% of cases. The mean length of the renal remnant was 2 cm (range 1-3.5 cm). Two cases showed a pelvic ectopic location that was not detected by US before involution. The remnant was removed during the same procedure. Anatomo-pathological findings were found to be compatible with dysplastic renal tissue. There were no intra- or postoperative complications. All patients had a mean length of stay of less than 24h.

CONCLUSIONS

Complete resolution on US does not mean disappearance of MCDK, as US does not detect renal dysplastic remnants after cyst involution has occurred. The retroperitoneoscopic approach to the renal and pelvic area is a minimally invasive, safe and effective procedure to diagnose and treat the renal dysplastic remnant in US-involuted MCDK.

Is screening for vesicoureteral reflux mandatory in infants with antenatal renal pelvis dilatation?

AIM

To determine whether postnatal ultrasound (US) can guide the use of voiding cystourethrography (VCUG) in infants with antenatally detected renal pelvis dilatation (ARPD).

METHODS

14,000 pregnant women consecutively underwent routine US examination during the second trimester. US examinations later in pregnancy were performed as follow-up of previous anomalies or on obstetrical indications. One hundred and six fetuses with ARPD > or =5 mm were identified. Two postnatal US examinations were performed in the newborns: on the 5th to 7th day and during the 3rd week of life. The findings were considered normal when renal pelvis dilatation (RPD) was < or =7 mm on both US examinations, and no calyceal or ureteric dilatation or signs of renal dysplasia or other anomalies were present. VCUG was done 6 to 8 wk after birth.

RESULTS

In 53 of 103 analysable infants, the postnatal ultrasonographic findings were normal. The VCUG was abnormal in three of these 53 infants, all with vesicoureteral reflux (VUR) grade I. Of 50 infants who had abnormal US examinations, six had VUR, four of which were grade IV and V reflux.

CONCLUSION

In infants with ARPD who undergo two postnatal US examinations with RPD < or =7 mm and have no other abnormalities, VCUG is unnecessary.

Ultrasound progression of prenatally detected multicystic dysplastic kidney

OBJECTIVES

To evaluate the sonographic involution of prenatally detected multicystic dysplastic kidney (MCDK).

METHODS

A total of 53 children with unilateral MCDK detected by prenatal ultrasonography between 1989 and 2004 were included in this analysis. All children received conservative management with follow-up visits every 6 months. Follow-up ultrasound examinations were performed at 6-month intervals during the first 2 years after birth and yearly thereafter. A linear mixed effect model was constructed, including MCDK length as the dependent variable and body size parameters and contralateral renal dimensions as independent variables.

RESULTS

The mean follow-up time was 68 months. A total of 334 ultrasound scans were analyzed. The ultrasound scan demonstrated partial or total involution of the MCDK in 48 cases (91%). A consistent negative correlation was found among MCDK length, patient age, and body size parameters. As a whole, the MCDK length reduction was estimated to be 0.29 mm/mo. The rate of reduction was not constant over time and was intense during the first 30 months of age. According to the regression model, MCKD reduced in length by 0.80 mm/mo during the first 30 months of age, 0.26 mm between 30 and 84 months old, and 0.30 mm in children older than 84 months.

CONCLUSIONS

Our results suggest a clear tendency of MCDK to decrease in size, with the rate of the involution greater during the first 30 months than the rate in older children.

Unilateral multicystic dysplastic kidney: long term outcomes

AIMS

To report the long term follow up of children with antenatally detected unilateral multicystic dysplastic kidney (MCDK) with documentation of complications, involution rate with time, and renal function at 10 years.

METHODS

Data were retrieved from a prospective regional registry of patients with MCDK between 1985 and 2004. Children were followed using a common protocol of investigation with follow up ultrasound scans (USS) at 2 (165 patients), 5 (117 patients), and 10 years (43 patients).

RESULTS

Serial USS showed that 33% of the MCDK kidneys had completely involuted at 2 years of age, 47% at 5 years, and 59% at 10 years. No patients developed hypertension, significant proteinuria, or malignancy, but two developed pelviureteric junction obstruction in the contralateral kidney. Twenty seven of 143 children (19%) had vesicoureteric reflux (VUR) (96% mild to moderate VUR) into the contralateral kidney with no difference in the incidence of urinary tract infections or renal scarring between those with or without VUR. The mean estimated glomerular filtration rate (GFR) was 86.4 ml/min/1.73 m2 (range 48-125) in 31 of 43 patients followed to 10 years.

CONCLUSIONS

Conservative management of unilateral MCDK is justified with clinical review and infrequent USS but longer term follow up continues in the 41% still with renal remnants at 10 years and those with impaired GFR. It is suggested that the initial micturating cystogram is deferred unless abnormal USS features are present in the contralateral kidney or ureter.

Indications for nephrectomy in children: what has changed?

OBJECTIVE

To review the indications for nephrectomy in children between 1990 and 2001, at the Starship Children's Hospital, Auckland, New Zealand.

PATIENTS AND METHODS

There were 206 nephrectomies. A retrospective review of the patients' notes was performed. The 12-year period was divided into two halves (1990-1996 and 1996-2001) which were then compared.

RESULTS

The total number of nephrectomies per year significantly increased over the period of the study (11.5 and 22.2 per year for 1990-1995 and 1996-2001, respectively; P<0.05), as did the number of partial nephrectomies (one and 23 for 1990-1995 and 1996-2001, respectively; P<0.01). Multicystic dysplastic kidney (MCDK), Wilms' tumour and vesico-ureteric reflux (VUR) accounted for more than half of the nephrectomies (60% and 68% for 1990-1995 and 1996-2001, respectively). The proportion of nephrectomies performed for these indications did not change (MCDK 25% and 34%, Wilms' 25% and 18%, VUR 16% and 18%, for 1990-1995 and 1996-2001, respectively), but fewer nephrectomies were performed for pelvi-ureteric junction (PUJ) obstruction in the second half of the study period (13% and 4% for 1990-1995 and 1996-2001, respectively; P<0.05).

CONCLUSION

The total number of nephrectomies, including partial nephrectomies, has increased significantly. The decrease in nephrectomies for PUJ obstruction could be accounted for by a more aggressive approach in the management and follow up of prenatally diagnosed hydronephrosis. Of note is that there was no significant change in the proportion of nephrectomies performed for Wilms' tumour, MCDK and VUR.

Outcome and cost analysis of laparoscopic or open surgery versus conservative management for multicystic dysplastic kidney

PURPOSE

To determine whether laparoscopic nephrectomy (LN), open nephrectomy (ON), or observation (OB) is most efficient for managing multicystic dysplastic kidney (MCDK).

METHODS

We performed a retrospective review of the management of our 12-year clinical experience of 32 MCDK patients to analyze the estimated total cost (ETC) of various treatment options and compare them with respect to survival, development of hypertension, and postoperative cosmetic appearance, to determine the most efficient treatment option.

RESULTS

There were 12 cases in the LN group, 6 in the ON group, and 14 in the OB group. ETC was lower for ON than for LN. But the length of preoperative observation and length of follow-up after spontaneous regression greatly affected ETC. If MCDK cases were observed > 5 years with standard investigations performed regularly, ETC was higher for the OB group than for the LN group. In 6/14 (42.9%) of OB cases, MCDK resolved within 5 years, and this subgroup had the lowest ETC up to the time of this review. Six cases initially in the OB group were managed surgically (4 by LN and 2 by ON) in accordance with parental requests, and ETC in these cases was highest. All cases are well after a mean follow-up of 5.7 years, without any impairment of renal function, or hypertension.

CONCLUSION

The decision to operate after lengthy observation increases costs. Overall, the most efficient surgical technique for managing MCDK was LN because of greater patient satisfaction with postoperative cosmesis. We recommend MCDK be treated by LN after a short period of observation.

Risk of hypertension with multicystic kidney disease: a systematic review

BACKGROUND

Children with multicystic kidney disease (MCKD) are increasingly managed conservatively, and are followed up throughout childhood because of the risk of hypertension highlighted in some reports. With this risk still poorly defined, the strategy and the duration of follow up do not seem to be based on evidence.

METHODS

Systematic review of the literature for all published cohort studies (prospective and retrospective) of children diagnosed to have unilateral MCKD and managed conservatively. Exclusion criteria were bilateral MCKD, and nephrectomy (not for hypertension) during the follow up period. For children with MCKD, the probability of developing hypertension during the follow up period was estimated.

RESULTS

From 29 reviewed studies, six cases of hypertension developed in 1115 eligible children. The mean probability of a child with unilateral MCKD developing hypertension was therefore 5.4 per 1000 (95% CI estimated at 1.9 to 11.7 per 1000).

CONCLUSION

Although the risk of hypertension in MCKD is low, the results of this study do not allow firm recommendations on the frequency and duration of blood pressure measurement follow up for these children. Large prospective cohort studies with a very long duration of follow up are needed.

Laparoscopic nephrectomy for unilateral multicystic dysplastic kidney in children

The contemporary management of children with unilateral multicystic dysplastic kidney remains controversial. With the potential risks of hypertension, infection, and malignant transformation of the dysplastic kidney, conservative management necessitates long-term review with frequent ultrasound scans, urine analyses, and blood pressure checks. Operative management has traditionally used open nephrectomy with its associated patient morbidity. The introduction of laparoscopic procedures has allowed the development of techniques that reduce patient morbidity, hospital stay, and analgesia requirement. This article reports a series of 13 children who underwent elective laparoscopic nephrectomy for unilateral multicystic dysplastic kidney and discusses the advantages this procedure has to offer for their management.

Predictive factors of ultrasonographic involution of prenatally detected multicystic dysplastic kidney

OBJECTIVE

To evaluate possible predictive factors of involution on ultrasonography (US) or disappearance of a prenatally detected multicystic dysplastic kidney (MCDK).

PATIENTS AND METHODS

Forty-five children with unilateral MCDK detected by prenatal ultrasonography between 1989 and 2002 were analysed. All patients except one had (99m)Tc isotopic scintigraphy to confirm the absence of renal function in the MCDK. All children were managed conservatively with follow-up visits every 6 months, with US 6-monthly during the first 2 years of life and yearly thereafter. Survival was analysed using the Kaplan-Meier method to evaluate the involution of the MCDK, with differences between subgroups assessed using the two-sided log-rank test. Cox's regression model was applied for the multivariate analysis.

RESULTS

The mean (range) follow-up was 50 (12-167) months; in all, 279 ultrasonograms were taken, the mean (range) number per patient being 6 (3-10). US showed partial involution of the MCDK in 30 (67%) cases and complete involution in nine (20%). The absolute MCDK length remained almost unchanged in six children (13%). Univariate analysis showed that four variables were possibly associated with complete involution of the MCDK (gender, impalpable kidney, renal length at admission using two thresholds, 62 and 78 mm). After adjusting by Cox's model only a renal length at diagnosis of <62 mm remained associated with complete involution (relative risk 8, 95% confidence interval 0.98-68; P = 0.05).

CONCLUSION

These results suggest that only a renal length of <62 mm on initial US was predictive of complete involution of the MCDK during the follow-up.

Concomitant anomalies in 100 children with unilateral multicystic kidney

OBJECTIVES

To determine the incidence and type of associated urogenital anomalies in children with a unilateral multicystic kidney and to assess in children with nephrectomy the additional diagnostic value of cystoscopy and, in girls, of colposcopy.

METHODS

This was a follow-up study of 100 fetuses with antenatally detected unilateral multicystic kidneys. After ultrasound confirmation of the diagnosis within a few days after birth voiding cystourethrography and isotope scan were performed in 83 of the surviving children to exclude vesicoureteral reflux and to establish renal function. Eighty-one children underwent nephrectomy and, prior to surgery, all underwent cystoscopy and girls also underwent colposcopy.

RESULTS

Seventy-five children had one or more additional urogenital anomalies: 39 had anomalies of the contralateral kidney, 40 had anomalies of the ipsilateral kidney and 30 had one or more anomalies of the lower urogenital tract. With cystoscopy 54 anomalies of the genitourinary tract were detected in 48 children and with colposcopy three anomalies were detected in 35 girls. Eighty-one children had a nephrectomy or heminephrectomy and 33 of them needed other urological intervention. Thirteen fetuses died (mostly from agenesis of the contralateral kidney) and six infants had no surgery at all.

CONCLUSION

Children with a unilateral multicystic kidney are at considerable risk of having other urogenital anomalies. When cystoscopy and colposcopy are added to routine investigations the rate of detection of anomalies is 75%, twice that reported in the literature.

PEDIATRIC UROLOGICAL CAUSES OF HYPERTENSION

PURPOSE

We reviewed the association of hypertension with several common pediatric urological conditions.

MATERIALS AND METHODS

We comprehensively reviewed the published literature linking hypertension with urinary tract infection, renal scarring, vesicoureteral reflux, multicystic dysplastic kidney, ureteropelvic junction obstruction and posterior urethral valves.

RESULTS

Hypertension is a recognized sequela of several common pediatric urological conditions. It is thought to be a direct consequence of renal damage or scarring often resulting from vesicoureteral reflux and/or febrile urinary tract infection. Multicystic dysplastic kidney has rarely been shown to cause hypertension when examined in large series rather than as isolated case reports. Ureteropelvic junction obstruction and posterior urethral valves have been linked to hypertension, although to our knowledge no series to date has specifically examined this relationship and smaller retrospective reviews seldom describe associated hypertension.

CONCLUSIONS

Several pediatric urological conditions are known to cause hypertension. However, methodological flaws in the literature, including a lack of standardized blood pressure followup, highly variable patient populations and poor control of concomitant urological abnormalities, greatly limit the ability to establish a causative link between any 1 specific condition and hypertension. Early diagnosis, the prevention of infection, close clinical followup and early intervention remain the primary means of preventing pediatric urological causes of hypertension.

Congenital renal tract anomalies: outcome and follow-up of 402 cases detected antenatally between 1986 and 2001

OBJECTIVE

To determine the long-term prognosis of antenatally detected renal tract anomalies in order to optimize parental counseling.

METHODS

This was a follow-up study of all renal tract abnormalities detected antenatally in a Level 3 ultrasound department between 1986 and 2001. Follow-up data (median age, 8 years) were retrieved from the records of the Paediatric Urology Department or the attending pediatrician.

RESULTS

A urinary tract anomaly was detected in 408 fetuses. There were four false-positive diagnoses. From two children follow-up data were incomplete, leaving 402 cases for analysis. A chromosomal abnormality was present in 7/81 (8.6%) fetuses that had karyotyping. Termination of pregnancy was performed in 55 (13.7%) cases and a further 66 (16.4%) children died during the perinatal period and up to 1 year of age. In 106/121 (26.4% of all fetuses) deceased children the cause of death was directly related to the renal tract anomaly. In the 281 surviving children a total of 545 renal tract anomalies were diagnosed postnatally, requiring a total of 381 surgical interventions in 156 infants. Outcome in survivors was generally good, with impaired renal function in nine infants and hypertension in three (4% of the survivors).

CONCLUSIONS

Congenital renal tract anomalies are associated with a high mortality rate, especially when they are structural developmental anomalies of the kidneys. Survivors require multiple operations, but the outcome is generally favorable. Ultrasound diagnosis, especially when made early, of non-lethal urinary tract anomalies may prevent additional renal damage by timing of delivery and early postnatal treatment.

Natural history of multicystic kidney conservatively managed: a prospective study

We report the long-term clinical results of conservative management of children with unilateral multicystic dysplastic kidneys (MCDK). Between 1989 and 2002, 43 children with MCDK detected by prenatal ultrasonography were prospectively followed. At birth, ultrasonography confirmed the prenatal findings in all cases. Patients underwent a radioisotope scan and micturating cystogram in order to confirm the diagnosis and to exclude other uropathies. Follow-up ultrasound (US) examinations were performed at 6-month intervals during the first 2 years of life and yearly thereafter. The mean follow-up time was 42 months (range 12-156 months). Two children developed hypertension during follow-up. In total 257 US scans were performed. The mean number of US scans per patient was 6 (range 3-10). US scans demonstrated partial involution of the MCDK in 30 (70%) cases and complete involution in 8 (19%). The absolute MCDK length remained almost unchanged in 5 children (11%). The estimated median time of complete involution of the MCDK was 122 months [95% confidence interval (CI)=86-158 months]. A total of 33 (76.7%) contralateral kidneys underwent compensatory hypertrophy, reaching a renal length above the 95th percentile during follow-up. The estimated median time for the occurrence of compensatory hypertrophy was 30 months (95% CI=15-45 months). In conclusion, the natural history of MCDK is usually benign but patients must have long-term follow-up with US scans and blood pressure measurements.

Unilateral multicystic dysplastic kidney: experience in children

OBJECTIVES

To report a retrospective study of unilateral multicystic dysplastic kidneys (MCDK) in children, assessing the contralateral kidneys and urinary tract, the functional consequences, and the urological and nephrological management and outcome, as unilateral MCDK is the most common cause of renal cystic disease in children, and malformations of the contralateral urinary tract and kidney (pelvi-ureteric obstruction, megaureter, reflux, renal dysplasia) have been reported.

PATIENTS AND METHODS

The study included 97 patients (60 boys, 37 girls) with MCDK seen between 1985 and 1998; 82 were diagnosed in utero by ultrasonography (US). After birth, the diagnosis was verified by US, renal scanning (in 93) or intravenous urography (in four), and 89 (92%) had voiding cysto-urethrography (VCUG). Of the 97 children, 87 (90% had a mean (range) follow-up of 44.3 (15-115) months.

RESULTS

The MCDK was removed in 17 children; the follow-up of 75 children (five lost to follow-up) showed total involution of the MCDK in 25%, shrinkage in 60% and a stable size in 15%. None had any sign of malignancy. The contralateral kidney showed anomalies in 19 of 97 children (20%); 12 had a dilated renal pelvis (two with megaureter), six had a high echogenicity of the contralateral kidney (one had reflux, and two also pelvic dilatation). In only four of the 89 children was reflux found by VCUG; 16 of the 19 anomalies were detected by US. Five children needed surgery on the contralateral urinary tract (three a pyeloplasty, and one each a pyeloplasty plus ureteroneocystostomy, and an antireflux procedure). Of the contralateral kidneys 43% showed compensatory hypertrophy. There was mild renal insufficiency in three children; renal function seemed to be slightly impaired in many. Five infants had hypertension (four with spontaneous resolution) caused by renal scarring after pyelonephritis or inborn dysplasia of the contralateral kidney. There were symptomatic urinary tract infections in seven children.

CONCLUSION

US can be used safely to diagnose unilateral MCDKs and malformations of the contralateral urinary tract and kidney. In cases where US of the dysplastic kidney remains uncertain renal scintigraphy is necessary to detect the lack of renal function. The low rate of reflux makes routine VCUG unnecessary if the contralateral upper urinary tract and kidney appear to be normal on US. Nephrectomy of the dysplastic kidney in typical cases is also unnecessary. A long-term nephro-urological follow-up of children with MCDK is recommended.

[Ambulatory blood pressure monitoring in multicystic dysplastic kidney disease]

OBJECTIVE

To evaluate blood pressure in a group of patients with multicystic dysplastic kidney (MDK) disease through ambulatory blood pressure (ABP) monitoring.

PATIENTS AND METHODS

ABP monitoring was performed in 16 patients with MDK disease using a Spacelabs 90207 monitor and an appropriately sized armband. The patients performed their normal daily activities except physical exercise. The activity period was 8:00 am to 8:00 pm and the resting period was midnight to 6:00 am. Patients with a percentage of correct readings of less than 70 % were excluded. The mean systolic and diastolic blood pressures for each period were calculated. Circadian variability was determined by the ratio between mean systolic and diastolic values in the active and resting periods, respectively. The results were compared with ABP values in healthy children.

RESULTS

Fourteen patients (mean age 16 3.1 years, range: 6-27.6) were included. No patients with hypertension were found through casual measurement. One patient had daytime systolic hypertension. Five patients presented an abnormal drop in blood pressure during sleep.

CONCLUSION

Blood pressure should be monitored in patients with MDK disease. ABP monitoring may detect alterations that can go unnoticed in casual determinations. Further studies with large samples are needed to establish the real prevalence of hypertension in these patients.

Renal cystic neoplasms and renal neoplasms associated with cystic renal diseases: pathogenetic and molecular links

Cystic renal neoplasms represent an isolated cystic mass not accompanied by cystic change of the renal parenchyma. Although cystic change may be seen in any type of renal neoplasm, a few (i.e., cystic renal cell carcinoma, cystic nephroma, cystic partially differentiated nephroblastoma, mixed epithelial and stromal tumor) are characterized by constant cystic change that may involve the entire tumor. Cystic kidney disease is characterized by cystic change, which usually involves the kidneys in a bilateral and diffuse pattern, does not create a discreet mass, and is due to hereditary or developmental conditions. Some of the cystic kidney diseases are not known to give rise to renal neoplasm; others such as autosomal polycystic kidney disease or multicystic dysplastic kidney may fortuitously coexist with renal neoplasms. Three conditions (acquired cystic kidney disease, tuberous sclerosis, and von Hippel-Lindau disease) are associated with renal neoplasms with such a high frequency that they are considered preneoplastic. This article reviews the differential diagnoses among cystic neoplasms. It also focuses on the underlying genetic and molecular mechanisms for the relationship between cystic renal diseases and renal neoplasms.

Unilateral multicystic dysplastic kidney: a combined pre- and postnatal assessment

OBJECTIVE

To review the prenatal assessment of associated renal pathology, non-renal pathology and renal biometry, fetal outcome and postnatal urological management in the presence of unilateral fetal multicystic dysplastic kidney.

METHODS

A total of 38 singleton pregnancies with fetal unilateral multicystic dysplastic kidney was studied over a 13-year period. Prenatally, fetal biometry, including head and abdominal circumferences and largest longitudinal diameter of the affected and contralateral kidneys, was performed. The amount of amniotic fluid was assessed. Fetal karyotyping was offered in cases of contralateral renal or non-renal pathology. A MAG 3 scan and voiding cystogram was performed approximately 4 weeks after delivery to establish renal function and to exclude urinary reflux.

RESULTS

Unilateral fetal multicystic dysplastic kidney was left-sided in 53% and right-sided in 47% of cases. The fetus was male in 63% and female in 37% of cases. Associated renal and non-renal pathology existed in 21% and 5% of cases, respectively. The fetal karyotype in these subsets was always normal. The longitudinal diameter of the multicystic dysplastic kidney was above the 95th centile in 87%. There was polyhydramnios in three cases and oligohydramnios in two cases. The prematurity rate was 16%. Postnatal examination revealed a non-functional multicystic kidney in 87% (33/38) of cases. Following surgical removal of the affected kidney, these infants progressed normally. Of the remaining five infants, four died because of associated anomalies and one infant developed normally without surgery.

CONCLUSIONS

Fetal outcome is determined by associated renal and/or non-renal structural pathology and not by the size/location of the unilateral multicystic dysplastic kidney or amniotic fluid volume.

Clinicopathologic features of nephrogenic rests and nephroblastomatosis

Nephrogenic rests are the consequence of residual metanephric tissue in a fully developed kidney. They usually occur along the perimeter of a mature renal lobe (i.e., perilobar), within the lobe itself (i.e., intralobar), or both (i.e., combined). Nephrogenic rests can be grossly obvious or microscopically discrete. Nephroblastomatosis designates nephrogenic rests that are multifocal or diffuse, and implies more extensive disease. Universal (panlobar) nephroblastomatosis denotes complete replacement of the renal lobe by nephrogenic tissue. The fate of nephrogenic rests and nephroblastomatosis varies and includes obsolescence, sclerosis, dormancy, hyperplasia, or neoplasia. Evidence strongly suggests that neoplastic transformation of nephrogenic rests results in Wilms' tumor (nephroblastoma). Nephrogenic rests almost always occur in the setting of Wilms' tumor; perilobar rests show a strong association with synchronous bilateral Wilms' tumors, whereas intralobar rests are more strongly associated with metachronous tumors. Genetic studies have shown that nephrogenic rests often share many of the same chromosomal defects as Wilms' tumor, which provides further evidence that they are precursors to nephroblastoma. Thus, nephrogenic rests are recognized as clinically significant entities requiring adequate detection and close surveillance. Heightened awareness regarding the clinical relevance of nephrogenic rests and nephroblastomatosis (1) has led to improved detection of these precancerous lesions, (2) fostered more intensive investigation into their biologic behavior, and (3) initiated in-depth discussions about potentially new treatment regimens. The pathologists' ability to identify and detect nephrogenic rests has benefited from the more efficient Beckwith classification. Radiologists have deployed high-resolution radiologic/imaging modalities to improve detection of nephrogenic rests in situ. Clinicians and surgeons are more aware of the impact that nephrogenic rests have upon patient management. Despite this progress, more data is needed to further define these lesions.

Multicystic dysplastic kidney and Kallmann's syndrome: a new association?

BACKGROUND

Kallmann's syndrome is characterized by anosmia and hypogonadotrophic hypogonadism. Radiographic studies of teenagers and older subjects with the X-linked form of the syndrome have shown that up to 40% have an absent kidney unilaterally. Although this has been attributed to renal "agenesis", a condition in which the kidney fails to form, little is known about the appearance of the developing urinary tract either pre- or post-natally in individuals with Kallmann's syndrome.

METHODS

We describe two brothers who had features of Kallmann's syndrome, most probably of the X-linked variety, who both had a major urinary-tract malformation detected before birth.

RESULTS

The brothers were found to have unilateral multicystic dysplastic kidneys on routine antenatal ultrasound scanning and both underwent surgical nephrectomy of these organs post-natally. Immunohistochemical studies on the younger sibling revealed hyperproliferative dysplastic kidney tubules which overexpressed PAX2, a potentially oncogenic transcription factor, and BCL2, a cell-survival factor, surrounded by metaplastic, alpha smooth-muscle actin-positive stroma: similar patterns have been observed in patients with non-syndromic multicystic dysplastic kidneys.

CONCLUSIONS

Our results describe a new type of urinary-tract malformation associated with Kallmann's syndrome. However, since multicystic kidneys tend to involute, only when more Kallmann's syndrome patients are screened in utero or in early childhood using structural renal scans, will it be possible to establish whether multicystic kidney disease is a bona-fide part of the syndrome.