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Saudi Journal of Kidney Diseases and Transplantation
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Year : 2011  |  Volume : 22  |  Issue : 1  |  Page : 67-71
The anomalies associated with congenital solitary functioning kidney in children

College of Medicine, Jordan University Hospital, Amman, Jordan

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Date of Web Publication30-Dec-2010


The aim of this study was to determine the incidence of associated urological and non-urological anomalies as well as the renal outcome in patients with a congenital solitary func­tioning kidney (CSFK). A retrospective review of 30 consecutive cases of CSFK seen at the pediatric renal service at the Jordan University Hospital between 2004 and 2008 was performed. There were 20 males and 10 females, whose ages ranged from five days to 14 years. In 20 patients (67%), the left kidney was absent. Associated anomalies were detected in 23 (77%) of the 30 patients; urological anomalies accounted for 47% (14/30) and non-urological anomalies were found in 19/30 (53%) patients. The latter included anomalies of the ear, nose and throat (ENT) in 9/30 (30%), musculoskeletal system (one with hypermobile joints) in 8/30 (27%), gastrointestinal (GI) in 7/30 (23%), cardiovascular (CV) in 4/30 (13%) and dermatological with epidermolysis bullosa, endocrine (euthyroid goiter) and gynecological (cervical cyst) in one patient each (3%). Proteinuria was seen in 6/30 (20%) and hypertension in 2/30 (7%) patients. Chronic renal failure (CRF) was seen in 6/30 (20%) patients, of whom three had end-stage renal failure (ESRF). CRF was seen mainly in patients with more than two associated urological anomalies. Idiopathic hyperuricosuria was found in five of the six tested patients (83%). In our study, the most common associated anomalies with CSFK were urological. The presence of more than two associated urological anomalies increased the risk of CRF.

How to cite this article:
Akl K. The anomalies associated with congenital solitary functioning kidney in children. Saudi J Kidney Dis Transpl 2011;22:67-71

How to cite this URL:
Akl K. The anomalies associated with congenital solitary functioning kidney in children. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2021 May 17];22:67-71. Available from: https://www.sjkdt.org/text.asp?2011/22/1/67/74351

   Introduction Top

There has been a surge in the number of pa­pers in the recent literature dealing with congenital solitary functioning kidney (CSFK), [1],[2],[3],[4],[5],[6],[7],[8],[9] which reflects the importance of the subject. CSFK is part of the spectrum of congenital anomalies of the kidney and urinary tract, [1],[2] which is the major cause of end-stage renal fai­lure (ESRF) in children and, to a much lesser extent, in adults. [10],[11] The CSFK may be the end result of unilateral renal agenesis (URA) or re­nal aplasia resulting from involution of a multi­cystic dysplastic kidney (MCDK) or a non­cystic dysplastic kidney. [3] It is difficult to deter­mine the exact etiology without serial antenatal ultrasound studies. The CSFK may be isolated or may be associated with urological and non­urological anomalies, or may occur as part of a syndrome. The purpose of this report is to review the CSFK and its associated anomalies and medical conditions in addition to the renal outcome.

   Patients and Methods Top

The medical records of 30 consecutive pa­tients with a CSFK seen at the pediatric renal service at the Jordan University Hospital bet­ween May 2004 and May 2008 were reviewed. Children who were discovered to have one functioning kidney were included while those with renal atrophy, aplasia, multicystic dysplas­tic kidney (MCDK) or subjected to nephrec­tomy were excluded.


Chronic renal failure:
Glomerular filtration rate <60 mL/min/1.73 m 2 . End-stage renal failure: GFR <15 m/min/1.73 m 2 .

Nephrotic syndrome: Proteinuria >40 mg/m 2/ hour.

Hyperuricosuria was defined as a 24-hour uri­nary uric acid excretion of >13 mg/kg/day and >10 mg/kg/day in children <2 years and >2 years, respectively. The duration of follow-up ranged from 1 to 48 months.

Renal ultrasonography was performed in all study subjects, micturating cystourethrogram (MCUG) was performed in 29 subjects and di­mercaptosuccinic acid renal scan (DMSA) was performed in 26 patients. A 99m Tc diethylene­triaminepenta acetic acid (DTPA) renogram was performed in a few patients. Six patients had 24-hour urine collection for uric acid and crea­tinine with concomitant serum uric acid and creatinine.

   Results Top

There were 30 consecutive children with a CSFK, including 20 males and 10 females. The age ranged from five days to 14 years. The left kidney was absent in 20 patients (67%). Seven patients (23%) had an isolated CSFK and 23/30 (77%) had 54 associated abnormalities. Four had one and the remaining had more than two associated anomalies. Urological anomalies were found in 14/30 patients (47%) and non-urolo­gical anomalies were found in 19/30 patients (53%).

There were three members of a triplet. The index case was investigated following a urinary tract infection (UTI) and was found to have a solitary kidney on the right side. Cystoscopy re­vealed an absent contralateral ureteral opening. On screening the other two siblings who were identical, both had an absent right kidney. Fa­mily history revealed consanguinity in eight and bilateral renal agenesis in a sibling of the triplets.

The associated anomalies are shown in [Table 1], [Table 2] and [Table 3].
Table 1: Distribution of the 23 study patients with anomalies according to type.

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Table 2: Associated urological anomalies in 14/30 study patients (47%).

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Table 3: Details of associated non-urological anomalies seen in patients with CSFK.

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Renal complications

Chronic renal failure (CRF) developed in 6/30 (20%) subjects, three (10%) of whom had end­stage renal failure (ESRF). CRF developed in one patient with one associated urological ano­maly and in five patients with more than two anomalies. Proteinuria was seen in 6/30 patients (20%), of whom one had nephrotic syndrome secondary to focal and segmental glomerulo­sclerosis (FSGS). Hyperuricosuria was seen in five of the six tested patients (83%) and hyper­tension was seen in 6.7% of the study subjects.

   Discussion Top

The CSFK may be associated with urological [12]­,[13],[14] and non-urological abnormalities. [7] True renal agenesis (RA) results from either failure of formation of the ureteric bud or absence of an interaction with the metanephric mesenchyme. [4],[5] In addition to true RA (no renal parenchyma and no function), cases such as renal aplasia (renal parenchyma but no function) [3] and invo­

luted MCDK are often misdiagnosed as RA. [1] Aslam et al reported complete involution of the MCDK by two, five and 10 years in 33, 47 and 59% of the cases, respectively. [15]

Genetic [1] and environmental factors [16] have an important role in the etiology of CSFK. The most common associated anomalies in our study were urological, with VUR and hydronephrosis being the most frequent, which is similar to that reported in other reports. [17]

In our study, all members of a triplet who had a sibling with bilateral renal agenesis had a solitary kidney and one had a double ureter in addition.

Schwaderer et al found an increased preva­lence of congenital renal anomalies (14.7%) in relatives of index patients with bilateral renal agenesis/dysplasia, the most common being solitary kidneys and duplicated urinary tracts. [6]

The most common non-urological anomalies in our series were ENT (26%) and GIT ano­malies (15%). This is different from the results of Dursun et al who found non-urological ano­malies in 44% of 87 consecutive cases of CSFK, with GIT and cardiac anomalies as the most common. [7] The most frequent ENT and GIT anomalies in our report were ear deformities and imperforate anus, respectively.

In a case-controlled study by Lizama et al, the association of isolated pre-auricular tags with nephro-urological anomalies was not statisti­cally significant. [18] On reviewing the available literature, we could not find previous associations between CSFK and epidermolysis bullosa. Genitourinary anomalies occur in 16.6% of EB simplex. [19] Likewise, the association of CSFK with hypermobile joints has not been mentioned in the literature. CRF developed in 20% of our patients, most of whom had more than two associated anomalies.

In general, children with a CSFK fare better than adults. [8],[20],[21] Hellerstein et al, who studied 96 children with a normal-appearing CSFK, found that further investigation is warranted if the estimated glomerular filtration rate (eGFR) is two standard deviations below the mean for age and sex. This was estimated to be 78 mL/ min/1.73 m 2 for children aged 1-2 years, 73 mL/min/1.73 m 2 for girls older than two years and boys aged 2-13 years and 70 mL/min/1.73 m 2 for boys older than 13 years. [9]

Hyperuricosuria was found in 83% of our study patients. The association of CSFK with idiopathic hyperuricosuria has not been men­tioned before. Rugiu et al reported an increased prevalence of hyperuricemia in adults with re­nal agenesis. [22] Uchida et al reported familial RA with hyperuricemia in three siblings with im­paired renal function. [23] The significance of idio­pathic hyperuricosuria remains to be determined.

In conclusion, the most common associated anomalies with CSFK were urological. The asso­ciation of CSFK with hypermobile joints and epidermolysis bullosa has not been reported before. It is difficult to predict which patient with CSFK will develop proteinuria or CRF. An abnormal renal ultrasound in the presence of more than two associated anomalies may be a red flag.

Patients with a CSFK should be followed pe­riodically for microalbuminuria. The significance of the associated idiopathic hyperuricosuria re­mains to be determined.

   References Top

1.Weber S, Moriniere V, Knuppel T, et al. Prevalence of mutations in renal developmental genes in children with renal hypodysplasia: Results of the ESCAPE study. J Am Soc Nephrol 2006; 17(10):2864-70.  Back to cited text no. 1
2.Kerecuk L, Schreuder MF, Woolf AS. Renal tract malformations: perspectives for nephro­logists. Nat Clin Pract Nephrol 2008;4(6):312-25.  Back to cited text no. 2
3.Hiraoka M, Tsukkahara H, Ohshima Y, Kasuga K, Ishihara I, Myumi Y. Renal aplasia is the predominant cause of congenital solitary kid­neys. Kidney Int 2002;61(5):1840-4.  Back to cited text no. 3
4.Zaffanello M, Brugnara M, Zuffante M, Franchini M, Fanos V. Are children with con­genital solitary kidney at risk for lifelong complications? A lack of prediction demands caution. Int Urol Nephrol 2009;41:127-35.  Back to cited text no. 4
5.Woolf AS, Hillman KA. Unilateral renal agenesis and the congenital solitary functioning kidney: developmental, genetic and clinical per­spectives. BJU Int 2007;99(1):17-21.  Back to cited text no. 5
6.Schwaderer AL, Bates CM, McHugh KM, Mc­Bride KL. Renal anomalies in family members of infants with bilateral renal agenesis/adys­plasia. Pediatr Nephrol 2007;22(1):52-6.  Back to cited text no. 6
7.Dursun H, Bayazit AK, Buyukcelik M, Soran M, Noyan A, Anarat A. Associated anomalies in children with congenital solitary functioning kidney. Pediatr Surg Int 2005;21(6):456-9.  Back to cited text no. 7
8.Seeman T, Patzer L, John U, et al. Blood pre­ssure, renal function, and proteinuria in children with unilateral renal agenesis. Kidney Blood Press Res 2006;29(4):210-5.  Back to cited text no. 8
9.Hellerstein S, Chambers L. Solitary kidney. Clin Pediatr 2008;47(7):652-8.  Back to cited text no. 9
10.Schedl A. Renal abnormalities and their deve­lopmental origin Nat Rev Genet 2007;8(10): 791-802.  Back to cited text no. 10
11.Horaoka M, Hori C, Tsukahara H, Kasuga K, Ishihara Y, Sudo M.Congenitally small kidneys with reflux as a common cause of nephropathy in boys. Kidney Int 1997;52(3):811-6.  Back to cited text no. 11
12.Yalavarth R, Parikh CR. Congenital renal agenesis: a review. Saudi J Kidney Dis Transpl 2003;14:336-41.  Back to cited text no. 12
13.Arena F, Arena S, Paolata A, Campenni A, Zuccarello B, Romeo G. Is a complete urolo­gical evaluation necessary in all newborns with asymptomatic renal ectopia? Int J Urol 2007; 14(6):491-5.  Back to cited text no. 13
14.Hitchcock R, Burge DM. Renal agenesis: an acquired condition? J Pediatr Surg 1994;29(3): 454-5.  Back to cited text no. 14
15.Aslam M, Watson AR; on behalf of the Trent & Anglia MCDK Group. Unilateral multicystic dysplastic kidney: long term outcomes. Arch Dis Child 2006;91(10):820-3.  Back to cited text no. 15
16.Nielsen GL Norgard B, Puho E, Rothman KJ, Sorensen HT, Czeizel AE. Risk of specific congenital abnormalities in offspring of women with diabetes. Diabet Med 2005;22(6):693-6.  Back to cited text no. 16
17.Cascio S, Paran S, Puri P. Associated urological anomalies in children with unilateral agenesis. J Urol 1999;162(3 part 2):1081-3.  Back to cited text no. 17
18.Lizama M, Cavagnaro F, Arau R, Navarrette O, Fontanaz AM, Garcia C. Association of isolated preauricular tags and nephrourological anomalies: case control study. Pediatr Nephrol 2007;22(5): 658-60.  Back to cited text no. 18
19.Fine J, Johnson LB, Weiner M, et al. Genito­urinary complications of inherited epidermo­lysis bullosa: experience of the National Epider­molysis Bullosa Registry and review of the literature, J Urol 2004;172:2040-4.  Back to cited text no. 19
20.Argueso LR, Ritchey ML, Boyle ET Jr, Milliner DS, Bergstralh EJ, Kramer SA. Prognosis of patients with unilateral renal agenesis. Pediatr Nephrol 1992;6(5): 412-6.  Back to cited text no. 20
21.Thorner P, Arbus GS, Celermajer DS, Baumal R. Focal segmental glomerulosclerosis and pro­gressive renal failure associated with a unil­ateral kidney. Pediatrics 1984;73:806-10.  Back to cited text no. 21
22.Rugiu C, Oldrizzi L, Lupo A, et al. Clinical fea­tures of patients with solitary kidneys. Nephron 1986;43(1):10-5.  Back to cited text no. 22
23.Uchida S, Akiba T, Sasaki S, et al. Unilateral renal agenesis associated with various metabolic disorders in three siblings. Nephron 1990;54(1): 86-8.  Back to cited text no. 23

Correspondence Address:
Kamal Akl
Consultant Pediatric Nephrologist, College of Medicine, Jordan University Hospital, P.O. Box 831373, Amman 11183
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PMID: 21196615

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  [Table 1], [Table 2], [Table 3]

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