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Saudi Journal of Kidney Diseases and Transplantation
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Year : 2003  |  Volume : 14  |  Issue : 3  |  Page : 290-295
Vesicoureteral Reflux in Childhood


Department of Pediatrics, Hacettepe University Faculty of Medicine, Pediatric Nephrology and Rheumatology Unit, Ankara, Turkey

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How to cite this article:
Duzova A, Ozen S. Vesicoureteral Reflux in Childhood. Saudi J Kidney Dis Transpl 2003;14:290-5

How to cite this URL:
Duzova A, Ozen S. Vesicoureteral Reflux in Childhood. Saudi J Kidney Dis Transpl [serial online] 2003 [cited 2019 Jul 22];14:290-5. Available from: http://www.sjkdt.org/text.asp?2003/14/3/290/32999

   Introduction Top


Vesicoureteral reflux (VUR), the retrograde flow of the urine from the bladder into the ureters, is present in 18 to 40 % of children evaluated for their first urinary tract infection (UTI). [1] Eight percent of girls and 2% of boys suffer from UTI during childhood. [2] The recognition of VUR and its significance has evolved over the past 40 years.


   Epidemiology and Pathogenesis Top


The prevalence of VUR in healthy children is uncertain. Ransley reported VUR in seven of 535 apparently normal neonates, infants and children (1.3%). [3] The frequency appears to be inversely proportional to age. Female to male ratio varies between 1:1 to 10:1; female­circumcision practice further affects this ratio. [4],[5]

VUR is a congenital and partially inherited disorder. Genetic factors may be associated with the development or the prognosis of VUR; for example polymorphism in the ACE gene has been associated with scar formation in VUR, as will be discussed below. [6],[7],[8] The mode of inheritance of VUR is not well under­stood. An autosomal dominant pattern had been suggested. [9] The prevalence of VUR among siblings of index patients varies between 11% and 67%, with mean prevalence of 32%. [10],[11] Hollowell performed a retrospective survey of studies which screened the siblings of patients with VUR, over a period of 17 years. [10] The mean prevalence of reflux in siblings was 32% (570 of 1768). Sibling age varied inversely with the prevalence of reflux. Twin relationship, and absent dysfunctional voiding symptoms in the index patient predicted a higher chance of reflux in a sibling. The prevalence of reflux and renal abnormality in siblings undergoing screening was 3%. Controlled studies are needed to determine the benefit of screening asympto­matic siblings.

Primary VUR associated with prenatal hydronephrosis usually affects males and is severe; on the other hand, VUR diagnosed after UTI is more common in females and is milder. [12]

Oblique entry of the ureter into the bladder and adequate length of the intramural ureter are the anatomic features which characterize the normal valve mechanism of ureterovesical junction. Primary VUR is not associated with any neuromuscular or obstructive disorder. The orifice of refluxing ureters are usually located laterally and more cephalad. In case of a duplicated collecting system, the lower segment ureteral orifice is abnormally located. Urethral obstruction, neuromuscular diseases and abnormal voiding patterns (dysfunctional voiding) cause secondary VUR. In every child with VUR, voiding dysfunction should be questioned thoroughly for the presence of unstable bladder. VUR is termed secondary in these cases and treatment is directed towards correcting the bladder dysfunction.

The grades of reflux are shown in [Table - 1]. A VCUG showing grade I reflux to the left and grade II reflux to the right kidney is shown in [Figure - 1].


   Clinical Features and Imaging Top


VUR is usually detected during assess­ment of children with UTI. With widespread use of fetal ultrasonography (US), increasing numbers of newborns are referred to pediatric nephrologists.

The Swedish guidelines suggest that the initial work-up at first diagnosed febrile upper UTI be as follows: [13]

Children below 2 years of age

US within 2-4 weeks

Voiding Cystourethrogram (VCU)

within 1-2 months

Children 2 years of age and older

US within 1-2 months

DMSA nuclear scan after 6-12 months.

If there are uptake defects or side distribution with one kidney having below 45 % of the total function, a VCU is added.

Recent findings support the view that DMSA scan may replace VCU in the initial work-up of children below 2 years of age; VCU can be applied when DMSA is abnormal.

Voiding cystourethrography enables the clinician to visualize the urethra, to grade reflux, to detect duplication or ureteral ectopia, posterior urethral valve, bladder trabeculation, bladder diverticula and foreign bodies. High gonadal irradiation is the major disadvantage of this technique.

Radionuclide cystography has limited capa­city for grading of VUR, but the radiation dose is 50-200 times less than with VCU. Radio-nuclide cystography is the ideal method for the follow-up of the patient and the screening of the siblings. [15]

Ilyas et al report that renal ultrasound (RUS) did not correlate with a positive DMSA renal scan; of the 146 children with normal RUS, 89 (61%) had a positive renal scan consistent with acute pyelonephritis. [16] In the same study, it was shown that VUR was more prevalent in younger children with febrile UTI than the older children: 51% in < 2 years age group, 47% in 2-8 years of age group, and 28 % in >8 years of age group.

Mahant et al reviewed the US and VCU of 162 children under five years of age with first episode of UTI. They showed that the sensi­tivity and specificity of ultrasound in suggesting VUR were 40% and 76 % respectively. [17]

VCU can be obtained once the urine is free of infection. Many pediatricians delay VCU for a period of two to six weeks after an acute UTI, believing that UTI per se may result in VUR or exacerbate VUR; i.e. increase its grade. However, recent studies have shown that the rate of detection of VUR in children with first episode of UTI does not increase when VCU is done early. [18] The advantages of doing the VCU early are convenience, compliance and avoidance of prophylactic antibiotics. Multicenter studies and/or a meta­analysis are needed to reach a final conclusion.

Voiding urosonography (VUS) is far from giving reliable results; anatomical conditions, patient co-operation and contrast medium administration are factors affecting the accu­racy of VUS.

[19] However, VUS can be used as a first diagnostic step in female babies and in the screening for VUR.


   Antenatal Hydronephrosis and VUR Top


Brophy et al. retrospectively reviewed children referred for evaluation of prenatally detected hydronephrosis. VUR was identified in 40 of 234 infants (21%), the incidence being higher with greater degrees of sonographic dilatation. [20]

Ismaili et al. prospectively followed 264 infants with antenatal renal pelvis dilatation. [21] Two US examinations were performed, first on day five and the second at one month after birth. Additionally, VCU was also per­formed on all patients. US abnormality was defined as pelvic AP diameter of 7 mm, calyceal or ureteral dilation, pelvic or ureteral wall thickening, absence of cortico-medullary differentiation, and signs of renal dysplasia. US was abnormal in 72% of the cases; among them 33% had abnormal VCU. Only five of the 74 patients who had normal US result had VUR (6.7%). They concluded that a urinary tract which appears normal on two successive neonatal ultrasonographic examinations rarely shows abnormal findings on VCU.


   Management Top


Prophylaxis: Any infant with suspicion of VUR should be put on antibiotic prophylaxis for UTI, until the imaging studies are completed. [22] Trimethoprim (TMP) + Sulfam­thoxazole (SMX) (2 mg of TMP, 10 mg of SMX per kg as single bed time dose or 2 mg of TMP, 10 mg of SMX per kg twice per week), nitrofurantion (1-2 mg/kg as single daily dose), sulfisoxazole (10-20 mg/kg divided every 12 h), nalidixic acid (30 mg/kg divided every 12 h), methanamine mandelate (75 mg/kg divided every 12 h) are some of the anti­microbials used for porphylaxis.

When VUR is identified, children should be maintained on anti-microbial prophylaxis. Urine cultures are recommended every 1-3 months, and at the time of any urinary symptoms. Blood pressure, height and serum creatinine levels should be followed. DMSA scan are repeated following any upper febrile UTI or cessation of prophylaxis.

Secondary reflux due to voiding dysfunction has emerged as an important issue in recent years. Voiding dysfunction should be specially inquired in children with reflux. In patients suffering from bladder instability anti­cholinergics and appropriate treatment are recommended. Patients with lazy bladder syndrome; i.e. infrequent voiders, may benefit from timed voiding. A high fiber diet, and a daily toilet habit are useful in patients suffe­ring from constipation For patients with grade I-III reflux and for infants below one year of age with any grade of reflux, medical management is suitable. [23] Uncontrolled, recurrent UTI, non-compliance to medical treatment or intolerance to antimicro­bials are reasons to consider anti-reflux surgery.

Severe grade V reflux beyond 1-2 years of age should be surgically corrected. [23]

When making a decision for a patient with grade IV reflux, age and compliance of the patient, frequency of UTIs, presence or absence of renal scarring should also be considered.

Many authors recommend surgical correction of unresolved VUR in adolescents; some others recommend cessation of prophylaxis and considering surgical intervention only in the presence of pyelonephritis, proven by a renal scan.

Thompson et al reviewed the records of patients with VUR in whom prophylactic therapy was discontinued either due to physician recommendation or patient non­compliance. A total of 122 patients were infection-free while on, and 124 patients were infection-free while off prophylactic therapy. [24]

The infection rate on and off prophylactic therapy was 0.29 and 0.24 UTI per patients per year. New scars were identified in five patients while on prophylactics and in seven after antibiotics were discontinued. They suggested that discontinuing antibiotics is reasonable and safe in patients in whom VUR fails to resolve.

The success rate of uretero-neocyctostomy exceeds 95%. [5] In endoscopic correction (injection of polytetrafluoroethylene or teflon paste subureterically at the ureterovesical junction: STING), the success rate is 76% with one injection and 85% after a second injection. [25] The recurrence rate after a follow­up period of 2-5.5 years was 12%. [26] Ureteral obstruction rate was 0.32%. Long-term conse­quences of the migration of polytetrafluoroe­thylene or teflon are unknown. A variety of alternative substances are investigated.


   Outcome and prognosis Top


Smellie et al evaluated the outcome of VUR in 226 adults. [27] The patients whose mean age was 27 years, were studied for 10-35 years. At presentation (mean age 5 years) all had VUR and UTI; 63% remained free from UTI, no new scar developed after puberty. At follow up, 17 adults had hypertension and/ or raised plasma creatinine, 16 of whom had scarred kidneys. Those with VUR, but no scarring, did not suffer serious consequences as adults.

In low grade (I-II) reflux with undilated ureters, approximately 75 to 85% will stop refluxing. In higher grades (III-IV) with dilated ureters, the cessation rate is in the range of only 25-30%. [28] The International Reflux Study in Children (European Branch) studied the outcome of VUR grade III or IV, followed over 10 years. [29] At 10 years, 15% of children had no reflux, 48% had VUR with dilatation and 37% had VUR without dilatation.

Disappearance of VUR was significantly associated with grade III versus grade IV, unilateral versus bilateral and age >5 years at entry versus age <5 years.

In a randomized trial, medical and surgical management of children (25 boys and 27 girls) with bilateral grade III-V VUR and bilateral nephropathy were compared. [30] The difference in the glomerular filtration rate (GFR) at four years between the two groups was not significant. The authors concluded that the main factor that determines outcome is the extent of renal parenchymal reduction and the degree of functional impairment at the start.

We examined the influence of deletion (D) and insertion (I) polymorphism in angiotensin I-converting enzyme (ACE) gene, PAI-1 on renal scarring in 94 children with III-IV degree reflux nephropathy. 6 On multivariate analysis DD genotype was the only factor that had a significant impact on renal scar for­mation, introducing a 4.9-fold risk (p<0.05).

Ohmoto et al studied the I/D polymorphisms of ACE gene in 78 patients with primary VUR. [7] The incidence of congenital unilateral small kidneys was high in DD patients. The GFR was 120.7 (35.7 in II genotype), 111.7 (33.3 in ID genotype) and 88.0 (18.0 in DD genotype). Hohenfellner et al reported a lower renal survival in DD genotypes compared to ID or II genotype [61% versus 89%, p<0.01].[8] Thus, the DD polymorphism may be regarded as one genetic modifying factor affecting prognosis, at least in the reported populations.

VUR is still the most common cause of chronic renal disease in children in many parts of the world. Careful management at the right time could save many such children and their families from lots of suffering and financial expenses.

 
   References Top

1.Dick PT, Feldman W. Routine diagnostic imaging for childhood urinary tract infection: a systematic overview. J Pediatr 1996; 128:15-22.  Back to cited text no. 1    
2.Hellstrom A, Hansson E, Hansson S, Hjalmas K, Jodal U. Association between urinary symptoms at 7 years old and previous urinary tract infection. Arch Dis Child 1991;66:232-4.  Back to cited text no. 2    
3.Ransley PG. Vesicoureteric reflux: continuing surgical dilemma. Urology 1978;12:246-55.  Back to cited text no. 3    
4.Tamminen-Mobius T, Brunier E, Ebel KD, et al. Cessation of vesicoureteral reflux for 5 years in infants and children allocated to medical treatment. The International reflux Study in children. J Urol 1992;148:1662-6.  Back to cited text no. 4    
5.Weiss R, Duckett J, Spitzer A. Results of a randomized clinical trial medical vs. surgical management of infants and children with grades III and IV primary vesicoureteral reflux (United States). The International Reflux Study in Children. J Urol 1992;148: 1667-73.  Back to cited text no. 5    
6.Ozen S, Alikasifoglu M, Saatci U, et al. Implications of certain genetic polymorphisms in scarring in vesicoureteric reflux: importance of ACE polymorphism. Am J Kidney Dis 1999;34:140-5.  Back to cited text no. 6    
7.Ohmoto Y, Nagaoka R, Kaneko K, Fukuda Y, Miyano T, Yamashiro Y. Angiotensin converting enzyme gene polymorphism in primary vesicoureteral reflux. Pediatr Nephrol 2001;16:648-52.  Back to cited text no. 7    
8.Hohenfellner K, Wingen AM, Nauroth O, Wuhl E, Mehls O, Schaefer F. Impact of ACE I/D gene polymorphism on congenital renal malformations. Pediatr Nephrol 2001; 16:356-61.  Back to cited text no. 8    
9.Report of a meeting of physicians at the Hospital for Sick Children, Great Ormond Street, London. Vesicoureteric reflux: all in the genes. Lancet 1996;348:725-8.  Back to cited text no. 9    
10.Hollowell JG, Greenfield SP. Screening siblings for vesicoureteral reflux. J Urol 2002;168:2138-41.  Back to cited text no. 10    
11.Sahin A, Ergen A, Balbay D, Basar I, Ozen H, Remzi D. Screening of asymptomatic siblings of patients with vesicoureteral reflux. Int Urol Nephrol 1991;23:437-40.  Back to cited text no. 11    
12.Herndon CD, McKenna PH, Kolon TF, et al. A multicenter outcomes analysis of patients with neonatal reflux presenting with prenatal hydronephrosis. J Urol 1999; 162:1203-8.  Back to cited text no. 12    
13.Jodal U, Lindberg U. Guidelines for manage­ment of children with urinary tract infection and vesicoureteric reflux. Recommendations from a Swedish state-of-art conference. Acta Pediatr Suppl 1999; 881:87-9.  Back to cited text no. 13    
14.Report of the International Reflux Study Committee. Medical versus surgical treatment of primary vesicoureteral reflux. Pediatrics 1981;67:392-400.  Back to cited text no. 14    
15.Willi UV, Treves ST. Radionuclide voiding cystography. In: Treves ST, ed. Pediatric Nuclear Medicine. New York: Springer­Verlag, 1985;105-120  Back to cited text no. 15    
16.Ilyas M, Mastin ST, Richard GA. Age-related radiological imaging in children with acute pyelonephritis. Pediatr Nephrol 2002;17:30-4.  Back to cited text no. 16    
17.Mahant S, Friedman J, MacArthur C. Renal ultrasound findings and vesicoureteral reflux in children hospitalised with urinary tract infection. Arch Dis Child 2002;86:419-20.  Back to cited text no. 17    
18.Mahant S, To T, Friedman J. Timing of voiding cystourethrogram in the investigation of urinary tract infections in children. J Pediatr 2001;139:568-71.  Back to cited text no. 18    
19.Valentini AL, De gaetano AM, Destito C, Marino V, Minordi LM, Marano P. The accuracy of voiding urosonography in detecting vesicoureteral reflux: a summary of existing data. Eur J Pediatr 2002;161:380-4.  Back to cited text no. 19    
20.Brophy MM, Austin PF, Yan Y, Coplen DE. Vesicoureteral reflux and clinical outcomes in infants with prenatally detected hydronephrosis. J Urol 2002; 168:1716-9.  Back to cited text no. 20    
21.Ismaili K, Avni FE, Hall M. Results of systemic voiding cystourethrography in infants with antenatally diagnosed renal pelvis dilation. J Pediatr 2002;141:21-4.  Back to cited text no. 21    
22.Practice parameter: the diagnosis, treatment and evaluation of the initial urinary tract infection in febrile infants and young children. American Academy of Pediatrics. Committee on Quality Improvement. Subcommittee on Urinary Tract Infection. Pediatrics 1999;103:843-52.  Back to cited text no. 22    
23.Rushton HG Jr. Vesicoureteral reflux and scarring. In: Barratt TM, Avner ED, Harmon WE, eds. Pediatric Nephrology, 4th edition. Pennsylvania: Lippincott Williams & Wilkins, 1999;851-871  Back to cited text no. 23    
24.Thompson RH, Chen JJ, Pugach J, Naseer S, Steinhardt GF. Cessation of prophylactic antibiotics for managing persistent vesi­coureteral reflux. J Urol 2001;166:1465-9.  Back to cited text no. 24    
25.Puri P, Ninan GK, Surana R. Subureteric teflon injection (STING). Results of a European survey. Eur Urol 1995;27:71-5.  Back to cited text no. 25    
26.Puri P. Endoscopic correction of primary vesi­coureteric reflux by subureteric injection of polytetrafluoroethylene. Lancet 1990;335:1320-2  Back to cited text no. 26    
27.Smellie JM, Prescod NP, Shaw PJ, Risdon RA, Bryant TN. Childhood reflux and urinary infection: a follow-up of 10-41 years in 226 adults. Pediatr Nephrol 1998;12:727-36.  Back to cited text no. 27    
28.Winberg J, Begstrom T, Jacobsson B. Morbidity, age and sex distribution, recu­rrences and renal scarring in symptomatic urinary tract infection in childhood. Kidney Int Suppl 1975 ;Suppl 4:S101-6.  Back to cited text no. 28    
29.Smellie JM, Jodal U, Lax H, Mobius TT, Hirche H, Olbing H. Outcome at 10 years of severe vesicoureteral reflux managed medically: Report of the International Reflux Study in Children. J Pediatr 2001;139:656-63.  Back to cited text no. 29    
30.Smellie JM, Barratt TM, Chantler C, et al. Medical versus surgical treatment in children with severe bilateral vesicoureteric reflux and bilateral nephropathy: a randomised trial. Lancet 2001;357:1329-33.  Back to cited text no. 30    

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Correspondence Address:
Seza Ozen
Hacettepe University Faculty of Medicine, Department of Pediatrics, Pediatric Nephrology and Rheumatology Unit, Sihhiye 06100, Ankara
Turkey
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