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.     

Ambulatory blood pressure monitoring in children with unilateral multicystic dysplastic kidney

Multicystic dysplastic kidney (MCDK) is one of the most common congenital renal anomalies. Arterial hypertension is a potential complication of MCDK. Blood pressure (BP) has so far been measured only casually and the frequency of hypertension has been estimated to be between 0%–8%. Ambulatory blood pressure monitoring (ABPM) provides more precise information on BP than the casual BP measurement. The aim of this study was to investigate the BP profile in children with MCDK using ABPM. A group of 25 children (16 girls), with a mean age of 7.8 years (range 3.8–17.7 years) were investigated. ABPM was performed using the oscillometric SpaceLabs 90207 device. Hypertension was defined as mean systolic and/or diastolic BP during the day and/or in the night exceeding 95th percentile for ABPM. Five (20%) children showed hypertension, two of them had combined daytime and night-time hypertension and three had isolated nocturnal hypertension, although daytime BP was between the 90th–95th percentile in two of them. Children with ultrasonographical and/or laboratory signs of contralateral kidney abnormalities showed a higher incidence of hypertension than those without abnormalities (two of four versus 3 of 21). The mean night-time systolic and diastolic BP of children with MCDK was significantly higher than in healthy children (+0.50 and +0.54 SDS, respectively, P=0.012 and 0.03, respectively). Three of the hypertensive children were already nephrectomised. All five hypertensive children showed ultrasonographical and/or laboratory signs of contralateral kidney abnormalities. Hypertensive children had significantly higher microalbuminuria than normotensive children (6.9 ± 3.2 mg/mmol creatinine versus 1.8 ± 0.7, P=0.03). The nocturnal BP fall (dip) was attenuated in five children, only one of whom was hypertensive. Conclusion Arterial hypertension in children with multicystic dysplastic kidney is seen more often if based on ambulatory blood pressure monitoring than on casual blood pressure recordings. The main risk factor for developing hypertension is contralateral kidney damage. Ambulatory blood pressure monitoring should be performed in children with multicystic dysplastic kidney, especially in those with contralateral kidney abnormalities. Received: 20 July 1999 and in revised form: 27 November 1999, 24 March 2000, 3 May 2000 Accepted: 3 May 2000     

Routine voiding cystourethrography is of no value in neonates with unilateral multicystic dysplastic kidney

OBJECTIVES: To determine if two successive ultrasound examinations could rule out the presence of clinically significant contralateral anomalies in neonates with multicystic dysplastic kidney (MCDK), thereby avoiding unnecessary voiding cystourethrography (VCUG). STUDY DESIGN: We followed 76 newborn infants with antenatally discovered MCDK. Two successive neonatal renal ultrasound examinations were performed, one within the first week and one at around 1 month of life. VCUG and isotopic studies were performed in all infants. RESULTS: Urologic anomalies of the contralateral kidney were present in 19 of 76 children (25%): vesicoureteral reflux (VUR) in 16 (21%), ureteropelvic junction obstruction in 2 (3%), and renal duplex kidney in 1 (1%). Sixty-one infants (80% of total) had normal contralateral urinary tract on the 2 successive neonatal renal ultrasound scans. Among them, 4 of 61 (7%) infants presented with low-grade VUR on VCUG that had resolved spontaneously before 2 years of age. The sensitivity, specificity, positive predictive value, and negative predictive value of two successive ultrasound scans in the neonatal period to predict contralateral urological anomalies on VCUG were 75%, 95%, 80%, and 93%, respectively. CONCLUSIONS: In infants with antenatally diagnosed MCDK, two successive normal neonatal renal ultrasound scans will rule out clinically significant contralateral anomalies, thereby rendering the need for a neonatal VCUG unnecessary.     

Single center experience in patients with unilateral multicystic dysplastic kidney

ObjectiveTo determine the clinical features, long-term outcomes, and additional urological anomalies of patients treated for multicystic dysplastic kidney (MDK).Materials and methodsPatients with MDK who were followed between January 2004 and October 2012 were reviewed retrospectively. Demographic, clinical, laboratory, and radiological data were evaluated.ResultsA total of 68 patients with MDK were followed for a mean period of 46.8 ± 32.4 months. MDK was detected by antenatal ultrasound in 64 (94.1%) of the patients. Ten patients had (14.7%) additional urological anomalies in contralateral kidney. Vesicoureteral reflux was found in five patients (7.3%). Other urological anomalies were megaureter (two), cortical renal cyst (two), ureteropelvic junction obstruction (one), and renal ectopy (one). Urinary tract infection was detected in 14 (20.5%) patients. Four (5.9%) patients had hypertension. Compensatory hypertrophy was detected in 29 (42.6%) patients. Eight (11.8%) of these 29 patients had glomerular hyperfiltration and three (4.4%) of these eight patients also had proteinuria. Follow-up ultrasound revealed complete involution in 19 (35.8%) patients. Nephrectomy was performed in 15 (22.0%) patients. Indications of nephrectomy were, recurrent urinary infection (four), hypertension (three), ureterocele (two), renal calculi (one), flank pain (one), hematuria (one), persistent large cystic kidney (three), and atypical US findings (two).ConclusionIn patients with MDK, depending on the clinical, laboratory, and radiological findings, appropriate timing of operation by multidisciplinary approach is important for early detection and treatment of any possible complications.     

儿童泌尿系感染临床管理现状分析

目的初步了解儿童泌尿系感染临床管理现状,为今后制订适于我国实际的临床指南提供参考。方法对自1994年至2003年间入院诊断泌尿系感染(泌感)的患儿病史进行回顾性分析,通过电话回访了解出院后的随诊情况。结果74例入院诊断泌感的患儿,最终仅有20例(27.0%)符合严格的泌尿系感染诊断标准。仅有11例(14.9%)完成多项影像学检查(包括B超及膀胱输尿管反流筛查),膀胱输尿管反流阳性2例。回访成功41例,其中仅13例(31.7%)出院后在门诊定期随诊,8/13例仍有反复泌尿系感染。结论①按照严格的泌尿系感染诊断标准,许多入院时的泌感诊断不能成立,将被纠正;②寻找泌感潜在病因时影像学检查不够充分,这可能是膀胱输尿管反流诊断率相对低(2/20例,10.0%)的原因之一;③泌感患儿随诊率极低,有碍于控制泌感复发。今后确应重视小儿泌尿系感染的严格诊断程序、影像学检查及随诊管理。     

Clinical features of unilateral multicystic renal dysplasia in children

A clinical study of 204 patients with unilateral multicystic renal dysplasia referred to 30 nephrology departments was undertaken to assess the frequency of complications in children who underwent nephrectomy (n=40) versus those who were treated conservatively (n=164). Six patients required antihypertensive treatment, 30 (13% of girls, 17% of boys) had at least one episode of urinary tract infection. The number of clinical complications did not differ in patients who underwent nephrectomy in comparison to those who did not. The dysplastic kidney decreased in size in 65% of kidneys with repeated ultrasound values; no change occurred in 16%, while an increase in maximal diameter was observed in 19%. Contralateral kidney length of more than 2 standard deviation scores (SDS) was seen in 30% of patients. There is evidence for a slight impairment of renal function in the whole study group given by a median of serum creatinine level of 0.63 SDS in all patients available for analysis. Among those 35 patients with contralateral anomalies (mainly obstructive changes and vesico-ureteral reflux), all 3 patients with contralateral changes suggestive of hypoplasia and 22% with obstruction, but only 1/7 (14%) with reflux showed elevated serum creatinine level >2 SDS. Conclusion Renal function seems to be slightly impaired in patients with unilateral multicystic renal dysplasia. The apparent tendency to regression of the dysplastic kidney and no difference in the number of complications justify a conservative management rather than operative intervention. Received: 9 May 1997 / Accepted in revised form: 16 February 1998     

Medical management of congenital anomalies of the kidney and urinary tract

Renal damage in children has been found to be more congenital in origin than was previously thought. Congenital anomalies of the kidney and urinary tract (CAKUT) involve renal dysplasia, renal hypoplasia, urinary tract obstruction and vesicoureteral reflux. CAKUT are sometimes bilateral and different types often coexist. Depending on their types and severity, children with CAKUT often have varying degrees of a reduced number of nephrons at birth. CAKUTare now the leading cause of renal failure in children. Children with renal dysplasia or obstructive uropathy may have abnormal renal tubules, and tend to lose essential water and sodium in urine. This can lead to poor body growth unless they are supplemented with water and sodium. Children with severe ureteric reflux often develop urinary infection and renal scarring. Renal scarring can further increase the risk of renal failure in children who already have other CAKUTand fewer nephrons than normal. Hypertension and proteinuria may develop in children with renal dysplasia and further aggravate renal function unless they are treated. Recent advances in the understanding and management of CAKUT make it possible for children with CAKUT to grow normally, have fewer complications such as urinary infection, have longer renal survival, and survive even with end-stage renal diseases through renal replacement therapy.     

小儿先天性发育不良肾的临床特点和治疗

目的 探讨小儿先天性发育不良肾的临床特点、诊断和治疗.方法 总结分析1988年至2009年我科收治的83例单侧先天发育不良肾的临床资料.所有患儿术前均行多普勒超声、静脉肾盂照影和99mTc-DTPA肾脏扫描.35例患儿行增强CT检查,39例行IVP后延迟CT检查三维重建.所有病例均行发育不良肾切除,肾切除的指征包括无功能发育不良肾脏合并临床症状55例,无临床症状的无功能多囊发育不良肾,随访不消退或增大27例,无功能发育不良肾合并肾输尿管积水1例.结果 各项术前检查中IVP后延迟CT三维重建技术阳性诊断率最高,达100%.术后病理均提示为发育不良肾脏.4例因高血压行发育不良肾切除的患儿,术后2例仍然有高血压,其他患儿术后临床症状消失,没有恶变者.结论 儿童先天发育不良肾脏发育不良程度不一,合并畸形不同,临床表现各异.IVP后延迟CT检查三维重建技术诊断发育不良肾脏阳性率高.合并临床症状的无功能发育不良肾、多囊发育不良肾长期随访不消退者可手术治疗,随访过程中有明显消退的多囊发育不良可定期观察,有功能的非多囊发育不良肾可以保留.近19%发育不良肾脏可合并对侧肾脏畸形,应密切监测对侧肾脏功能及血压.     

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

ObjectiveTo evaluate the impact of imaging modalities on the evaluation and prognosis of children with multicystic dysplastic kidney (MCDK) disease.Patients and methodsA 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.ResultsAt 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.ConclusionsThe 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.     

Hypertension and microalbuminuria in children with congenital solitary kidneys

Aim:   According to the hyperfiltration hypothesis, a low nephron endowment will lead to hyperfiltration in the remaining glomeruli and is associated with systemic hypertension, proteinuria and glomerulosclerosis. Being born with one functioning kidney instead of two, for instance because of unilateral renal agenesis or multicystic dysplastic kidney, is a cause of congenital renal mass reduction.
Methods:   In order to study the effect of congenital renal mass reduction on renal function and blood pressure, a retrospective chart review of 66 patients at the Pediatric Renal Center of the VU University Medical Center was performed. As intrauterine growth restriction is associated with a low nephron endowment, the additional effect of birthweight was also studied.
Results:   A total of 50% of patients with congenital renal mass reduction is found to be hypertensive, using anti-hypertensive drugs, and/or having microalbuminuria (>20 μg/min). Patients born small for gestational age have significantly smaller kidneys and lower estimated glomerular filtration rate than patients with a normal birthweight.
Conclusions:   We conclude that microalbuminuria and/or hypertension is present in 50% of patients with congenital solitary kidneys, which warrants a systematic follow-up of blood pressure, proteinuria and renal function in all patients with congenital solitary functioning kidneys, especially in patients with a low birthweight.     

Multicystic dysplastic kidney and pelviureteric junction obstruction

Two infants with nonfunctioning antenatally detected multicystic dysplastic kidneys developed acute renal failure in conjunction with pelviureteric obstruction of the contralateral kidney at 9 and 14 months of age, respectively. The initial postnatal ultrasounds had shown mild pelvic dilatation in both cases. Clinicians need to be aware of the possibility of late obstruction. We suggest that it is good practice to review patients with antenatally detected urinary tract abnormalities and equivocal investigations at joint nephrouroradiology meetings.     

婴幼儿发热性尿路感染的影像学检查评价

目的 探讨肾脏超声检查(US)、放射性核素肾静态扫描(DMSA)和排泄性膀胱尿道造影(VCUG)检查在婴幼儿发热性尿路感染(UTI)中的应用价值.方法 发热性UTI患儿人院1周内进行US及DMSA检查,2周后进行VCUG检查,急性期DMSA异常者6个月复查,并对US、DMSA和VCUG检查结果进行回顾性分析.结果 婴幼儿发热性UTI患儿160例,急性期接受US、DMSA和VCUG三项检查的共75例,VCUG检出VUR患儿23例(35个VUR肾输尿管单位),检出率为30.7%;35个VUR肾输尿管单位中,Ⅰ级反流0个,Ⅱ级8个(22.9%).Ⅲ级11个(31.4%),Ⅳ级14个(40.0%),V级2个(5.7%).35个反流肾输尿管单位中,US提示反流的有15个;无反流的114个肾输尿管单位中US提示反流的有12个,US筛查VUR的敏感性为42.9%,特异性为89.5%,阳性预测率为55.6%,阴性预测率为83.6%.35个反流的肾输尿管单位中,DMSA提示异常的有31个;无反流的114个肾输尿管单位中,DMSA提示异常的有61个,DMSA筛查VUR的敏感性为88.6%,特异性为46.5%,阳性预测率为33.7%,阴性预测率为93.0%.24例6个月后DMSA复查发现肾瘢痕形成15例,占62.5%,其中VUR患儿有10例,反流程度均为Ⅲ级或Ⅲ级以上.结论 发热性UTI婴幼儿中VUR的发生率高,以严重VUR多见,且容易形成肾瘢痕,US、VCUG和DMSA均应作为常规评估检查.