Incontinence in a Child with a Duplex Kidney: Case Report

CASE REVIEW Incontinence in a Child with a Duplex Kidney: Case Report Toby F. Handler, MD, Ellen Shapiro, MD New York University School of Medicine, New York, NY Persistent incontinence after toilet training in young girls and urinary tract infections or epididymitis in prepubertal boys should raise suspicion of an ectopic ureter. This often occurs in the context of duplication of kidney structures or other parenchymal abnormalities. The presence or absence of reflux affects surgical treatment, which may consist of ureteral reimplantation, ureteroureterostomy, and/or upper pole nephrectomy. [Rev Urol. 2002;4(1):44–48] © 2002 MedReviews, LLC Key words: Duplex kidney • Ectopic ureter • Childhood urinary incontinence A newborn girl had a single-vessel cord. A renal sonogram showed a right duplex system and a normal left kidney. An intravenous pyelogram (IVP) demonstrated complete duplication on the right side. The voiding cystourethrogram (VCUG) showed left grade 2/5 vesicoureteral reflux. The child was placed on prophylactic antibiotics. At 2 years of age, the VCUG showed resolution of the reflux. By age 4, she had not developed daytime urinary continence, despite a normal voiding pattern and normal bowel habits. Physical examination revealed no abdominal mass. The introitus was normal except that there was intermittent pooling of urine at the posterior fourchette. The spinal exam was unremarkable. A urinalysis was microscopically negative. 44 VOL. 4 NO. 1 2002 REVIEWS IN UROLOGY Incontinence in a Child with a Duplex Kidney A renal sonogram showed that the right duplex system measured 9.7 cm (Figure 1A). There was no hydronephrosis, and the parenchyma appeared normal. The left kidney measured 6.8 cm (Figure 1B). A VCUG showed grade 2 to 3/5 vesicoureteral reflux (Figure 2) associated with the right lower pole moiety. The history, physical examination, and radiographic findings were suggestive of a right upper pole ectopic ureter, and cystoscopy and bilateral ureteral reimplantation were recommended. On endoscopy, two ureteral orifices were seen on the right hemitrigone and a single, normally positioned orifice was noted on the left. Vaginoscopy demonstrated a single cervix and a normal vaginal vault. No further surgery was performed at that time. Because the right upper pole ureter was not ectopic, further evaluation was needed to determine the etiology of the incontinence. Magnetic resonance imaging (MRI) of the abdomen demonstrated a dysplastic left upper pole moiety with dilatation of the proximal ureter, which appeared to enter the proximal urethra or the vagina (Figure 3). The patient returned to the operating room. Cystoscopy did not reveal an orifice in the proximal urethra. On vaginoscopy, a submucosal tubular structure was seen along the left anterolateral wall of the vagina, but a definitive orifice was not identified. At surgery, two ureters were identified extravesically on the left. The lower 5–6 cm of the left ectopic upper pole ureter were stenotic, but the ureter was dilated proximally. A right common sheath ureteral reimplantation and a left lower pole ureteral reimplantation were performed. A left upper to lower pole ureteroureterostomy was then performed in the mid-pelvis. The postoperative course was uncomplicated, and the patient had satisfactory urinary continence following removal of the suprapubic tube. Her early postoperative sonogram shows mild dilatation of the upper and lower pole systems. A technetium-99m mercaptoacetyl triglycine (MAG-3) scan at 6 weeks demonstrated satisfactory drainage of all functioning systems. A VCUG showed no reflux. than 80% of ectopic ureters drain duplicated systems, whereas in males the majority of ectopic ureters drain single systems.1,2 The most common sites for termination of an ectopic ureter are the urethra and vestibule in the female1 and the posterior urethra in the male. Embryology For a clear understanding of the clinical manifestations of ectopic ureter in the male and female, the embryology of the ureteral bud will be reviewed. Figure 2. VCUG showing grade 2 to 3/5 reflux associated with the right lower pole moiety. Discussion Incidence The true incidence of ectopic ureter is unknown, as many cause no symptoms. Ectopic ureter occurs more frequently in females than in males, with a ratio of 6:1. In females more Figure 1. Renal ultrasound showing the right duplicated system, measuring 9.7 cm (A), and the left kidney, measuring 6.8 cm (B). A B VOL. 4 NO. 1 2002 REVIEWS IN UROLOGY 45 Incontinence in a Child with a Duplex Kidney continued At about 4–6 weeks’ gestation, the distal aspect of the mesonephric duct, the common excretory duct, is absorbed into the urogenital sinus. As it is absorbed, the ureteral bud and the mesonephric duct acquire separate orifices. The ureteral orifice migrates from a medial and caudal position to a lateral and cephalad position. The mesonephric duct rotates anterior to the ureter and migrates medially and caudally to the urethral portion of the urogenital sinus. Normal ureteral anatomy is dependent on this process of migration and rotation of the ureteral bud and mesonephric duct. If the ureteral bud arises from a more cranial position, the ectopic ureteral orifice is carried caudally with the mesonephric duct. Therefore, it may terminate at a point along the course of the mesonephric duct. Although the ureter commonly terminates in the prostatic urethra in males, it less frequently terminates in the seminal vesicles or ejaculatory duct and vas deferens. In females, the involuting mesonephric duct becomes Gartner’s duct. It may be incorporated here or into any of the nearby müllerian duct structures, such as the vagina, uterus, cervix, or fallopian tubes.3 Duplication of the ureters results from the existence of two separate ureteral buds arising from the mesonephric duct. The ureteral bud closest to the urogenital sinus, the lower pole ureter, is absorbed into the urinary tract first and may be more cranial and lateral than normal. The upper pole ureter remains associated with the mesonephric duct longer, and its orifice is caudal and medial to that of the lower pole. This anatomic relationship between the upper and lower pole ureters, achieved by rotation and migration, is determined by the Weigert-Meyer law.4 Renal dysplasia is often associated with ureteral ectopia. Mackie and Stephens showed that the greater the distance of the origin of the ureteral bud from the middle section of the mesonephric duct, the more abnormal the induced renal segment.5 Presentation The most common presenting symptoms of an ectopic ureter are urinary tract infection and incontinence.6 Other signs or symptoms, especially in the neonate, include an abdominal mass due to massive hydronephrosis (8%) and failure to thrive (2%). Ectopic ureters may be asymptomatic in childhood and remain undiagnosed until adulthood. The classic presentation, though, of an extravesical, infrasphincteric ectopic ureteral orifice in a girl is a lifelong history of persistent enuresis or dribbling associated with otherwise normal voiding habits.7 About half of females with ectopic ureters present with urinary incontinence. Adult females may present with incontinence due to relaxation of the urogenital diaphragm, through which the ureter travels.3 In males, the ectopic orifice is never distal to the urethral sphincter but may be incorporated into the mesonephric duct derivatives. Only one case of incontinence secondary to an ectopic ureter has been reported in a male.8 Figure 3. (A) MRI of the abdomen demonstrates a left dysplastic duplicated system with an upper pole moiety. (B) The upper pole ureter appears to enter the proximal urethra or the vagina. 46 VOL. 4 NO. 1 2002 REVIEWS IN UROLOGY Incontinence in a Child with a Duplex Kidney Therefore, recurrent epididymitis or a seminal vesicle mass may be the initial finding.9 Because acute epididymitis is IVP. The usual radiographic finding is a nonvisualized or poorly functioning upper pole of a duplex Ectopic ureters may be asymptomatic in childhood and remain undiagnosed until adulthood. uncommon in the prepubertal male, its occurrence should lead one to consider the possibility of an ectopic ureter. Diagnosis/Radiographic Studies With the advent of fetal ultrasonography, the radiographic findings associated with ectopic ureters are being detected prenatally. If hydronephrosis is isolated to the upper pole of a duplex system, the diagnosis of ectopic ureter should be considered.1 In a young girl, the diagnosis can often be made by physical examination. Direct visualization of the introitus may reveal continuous urinary leakage, and often an orifice is seen in the vestibule. Ultrasound can be useful in identifying a hydronephrotic collecting system and dilated ureter at the level of the bladder.1 The ectopic ureter can be mistaken at times for a ureterocele, which is thin-walled and par- system that may be hydronephrotic. The upper pole displaces the lower pole downward, producing the classic “drooping lily" sign. However, there is frequently a long delay in the diagnosis of an ectopic ureter, especially when it drains a nonfunctioning, nonhydronephrotic dysplastic renal unit with no ureteral dilatation. With the advent of fetal ultrasonography, the radiographic findings associated with ectopic ureters are being detected prenatally. When the ureter is not markedly dilated, there may be only subtle displacement of the lower pole pelvis or a small increase in distance between the vertebral column and the lower pole ureter. One must also identify the kidney associated with the ectopic ureter, since bilateral duplex systems are not uncommon. Malek and associ- Only one case of incontinence secondary to an ectopic ureter has been reported in a male. tially intravesical. With ectopia, there is a thick bladder wall between the bladder and the ureteral lumina.1 In most instances, the diagnosis of an ectopic ureter is confirmed by seven females with ectopic ureters draining dysplastic kidneys.11 They found that each patient underwent a mean of 10 diagnostic procedures and received one or more inaccurate diagnoses and inappropriate treatments. Also, the time from initial presentation to definitive diagnosis was a mean of 5.7 years. In cases where an ectopic ureter is suspected but there is no evidence of an upper pole segment, computed tomography or MRI is indicated.12 A cyclic VCUG should be performed to assess reflux into the ectopic ureter, as well as into the lower pole ureter. Lower pole reflux ates and Mandell and colleagues report that bilateral ureteral ectopia is not diagnosed on excretory urography in 5% –15% of cases.6,10 In another study, Carrico reported on is seen in at least half of cases. The presence or absence of reflux will affect surgical treatment. Also, if there is concern about the salvageability of the upper pole moiety, isotopic renal scanning using technetium-99m dimercaptosuccinic acid or technetium-99m MAG-3 should be performed. If the ectopic ureter is not identified in the urethrovaginal septum on physical examination, the ectopic orifices may be seen at the time of cystourethroscopy and vaginoscopy with careful inspection of the vesical neck, urethra, and vagina. Treatment Because most ectopic ureters are associated with poorly functioning Main Points • Ectopic ureter occurs six times more frequently in females than in males. • Urinary tract infection and incontinence are the most common presenting symptoms. • The most important imaging studies are ultrasound, voiding cystourethrogram, intravenous pyelogram, computed tomography, isotopic renal scanning, and magnetic resonance imaging. • Because most ectopic ureters are associated with poorly functioning renal parenchyma, an upper pole nephrectomy is recommended along with ureteral reimplantation. VOL. 4 NO. 1 2002 REVIEWS IN UROLOGY 47 Incontinence in a Child with a Duplex Kidney continued renal parenchyma, an upper pole nephrectomy is recommended.1 For ectopic ureters entering the bladder neck or urethra, the dissection is carried just beyond the level of the aortic bifurcation, where the ureters may enter a common sheath and are not easily separable. In this situation, the common ureteral wall of the ectopic ureter is left in place to avoid injury to the blood supply of the lower pole ureter. If there is no reflux, the ureteral stump may be left open. If reflux is present, a suture is placed to obliterate the lumen. If the upper pole is salvageable and no reflux is present, a ureteropyelostomy is performed. Following partial nephrectomy, there may be persistent lower pole reflux, necessitating continuous preventive antibiotics. Recommendations for the timing of reimplantation of the ureter are the same as for surgical intervention for primary reflux, because low grades of reflux often resolve.13 When the upper pole has functional parenchyma and is associated with 48 VOL. 4 NO. 1 2002 REVIEWS IN UROLOGY ipsilateral high-grade lower pole reflux, a common sheath ureteral reimplantation is performed. In our patient, the distal 6 cm of the ectopic ureter were stenotic. Therefore, an upper to lower pole ureteroureterostomy was performed in the pelvis with reimplantation of the lower pole ureter. Conclusion One should have a high index of suspicion for an ectopic ureter in girls with persistent incontinence and a normal voiding pattern following toilet training and in prepubertal boys with urinary tract infections or epididymitis. The appropriate imaging studies should be obtained and carefully interpreted. If an ectopic ureter is found, surgical reconstruction should be planned depending on the degree of renal function and the presence of vesicoureteral reflux. References 1. Schlussel RN, Retik AB. Anomalies of the ureter. In: Walsh PC, Retik AB, Vaughan ED, Wein AJ, eds. Campbell’s Urology. 7th ed. Philadelphia: W.B. Saunders; 1998;2:1814-1858. Ahmed S, Barker A. Single system ectopic ureters: a review of 12 cases. J Pediatr Surg. 1992;27:491–496. 3. Shapiro E. The ectopic ureter. AUA Update Series. Houston, TX: AUA Office of Education; 1990;9:242–247. 4. Meyer R. Development of the ureter in the human embryo: a mechanistic consideration. Anat Rec. 1942;96:355. 5. Mackie GG, Stephens FD. Duplex kidneys: a correlation of renal dysplasia with position of the ureteral orifice. J Urol. 1975;114:274–280. 6. Mandell J, Bauer SB, Colodny AH, et al. Ureteral ectopia in infants and children. J Urol. 1981;126:219–222. 7. Borer JG, Bauer SB, Peters CA, et al. A single system ectopic ureter draining an ectopic dysplastic kidney: delayed diagnosis in the young female with continuous urinary incontinence. Br J Urol. 1998;81:474–478. 8. Ejaz T, Malone PS. Male duplex urinary incontinence. J Urol. 1995;153:470–471. 9. Williams DI, Royle M. Ectopic ureter in the male child. Br J Urol. 1969;41:421–427. 10. Malek RS, Kelalis PP, Strickler GB, et al. Observations on ureteral ectopy in children. J Urol. 1972;107:308–313. 11. Carrico C, Lebowitz RL. Incontinence due to an infrasphincteric ectopic ureter: why the delay in diagnosis and what the radiologist can do about it. Pediatr Radiol. 1998;28:942–949. 12. Braverman RM, Lebowitz RL. Occult ectopic ureter in girls with urinary incontinence: diagnosis by using CT. AJR Am J Roentgenol. 1991;156:365–366. 13. Hussman DA, Allen TD. Resolution of vesicoureteral reflux in completely duplicated systems: fact or fiction? J Urol. 1991;145:1022–1023. 2.