Background
Ureterocele and ectopic ureter are the two main anomalies associated with a complete renal duplication. At present, antenatal ultrasonography detects both conditions in the majority of cases and diagnosis is confirmed after birth by further examination. Later on in life, these anomalies are revealed by clinical symptoms: urinary tract infection (UTI), pain, disturbances of micturition and urinary incontinence.
Ureterocele
Ureterocele is a cystic dilatation developed on the intravesical part of the ureter corresponding to the upper pole of a renal duplication. It is more frequent in females than in males, the overall prevalence being 1 in 4,000 births.
Ectopic Ureter
Ectopic ureter is less frequent than ureterocele (1 in 40,000 births), but is again more common in females (male to female ratio, 1:5). Eighty percent of ectopic ureters are associated with a complete renal duplication.
In females, the ureteral orifice may be located:
- In the urethra, from bladder neck to meatus (35%)
- In the vaginal vestibule (30%)
- In the vagina (25%)
- In the uterus and Fallopian tube (rarely)
In males, the ureteral orifice may be located:
- In the posterior urethra above the verumontanum and never below the external sphincter (60%)
- In the seminal tract (vas deferens, ejaculatory ducts, seminal vesicles) (40%)
Classification
Ureteroceles are usually obstructive for the upper pole moiety, but the degree of obstruction and functional impairment is variable according to the type of ureterocele and upper pole dysplasia. In the orthotopic form, there is often no, or only mild, obstruction and frequently the function of the moiety is normal or slightly impaired; the corresponding ureter may be dilated. In the ectopic form, the upper pole is altered, frequently dysplastic and hypofunctional or non-functional. The corresponding ureter is a megaureter. In the caecoureterocele (see definition below), the upper pole of the renal duplication is always dysplastic and nonfunctional.
Ectopic Ureterocele
Ectopic ureterocele is the most common form of ureterocele (>80%) and occurs bilaterally in about 40% of cases. It is voluminous, dissociating the trigone and slipping into the urethra, and can rarely prolapse through the urethral meatus. The ureterocele orifice is tight, rarely large, and located near the bladder neck, either in the bladder itself or in the urethra below the bladder neck. The ureter corresponding to the lower pole moiety is raised by the ureterocele and is frequently refluxing or compressed by the ureterocele, leading to an obstructive megaureter. A contralateral renal duplication is associated in 50% of cases. Occasionally, very large ureteroceles are responsible for reflux or obstruction of the contralateral upper tract.
Orthotopic Ureterocele
Orthotopic ureterocele accounts for 15% of cases. It is exclusively observed in females, and is small and located strictly intravesically. Orthotopic ureteroceles are mostly combined with a single kidney system.
Caecoureterocele
Caecoureterocele is very rare, occurring in less than 5% of cases. It is associated with an ectopic ureter and located in the urethra below the bladder neck.
Diagnosis
Ureterocele
Prenatal ultrasound reveals easily voluminous obstructive ureteroceles. In cases of a very small upper pole or a slightly obstructive ureterocele, prenatal diagnosis will be difficult. If prenatal diagnosis has been impossible, the following clinical symptoms - beside incidental findings - can reveal the congenital anomaly at birth or later:
- At birth, a prolapsed and sometimes strangulated ureterocele may be observed in front of the urethral orifice. In a newborn boy, it might cause acute urinary retention, simulating urethral valves.
- The early symptom of pyelonephritis in either sex may lead to the diagnosis.
- Later symptoms can include dysuria, recurrent cystitis and urgency.
In cases of prenatal diagnosis at birth, ultrasonography confirms the ureteral dilatation ending at the upper pole of a renal duplication. It also demonstrates the presence of an ureterocele in the bladder, with a dilated ureter behind the bladder.
At this point, it is important to assess the function of the upper pole using nuclear renography in the region of interest. Magnetic resonance urography may visualize the morphological status of the upper pole and lower moieties and of the contralateral kidney. A voiding cystourethrography (VCUG) is mandatory in identifying an ipsilateral or contralateral reflux and to assess the degree of intraurethral prolapse of the ureterocele.
Urethrocystoscopy may reveal the pathology in cases where it is difficult to make the differential diagnosis between ureterocele and ectopic megaureter.
Ectopic Ureter
Most of the ectopic megaureters are diagnosed primarily by ultrasound. In some cases, clinical symptoms can lead to diagnosis:
- In neonates: dribbling of urine, pyuria and acute pyelonephritis
- An ectopic orifice may be found in the meatal region. Significant vaginal discharge may be the equivalent of incontinence in little girls
- In pre-adolescent males: epididymitis is the usual clinical presentation and a palpable seminal vesicle may be found on digital rectal examination
Ultrasonography, nuclear studies, voiding cystourethrogram (VCUG), magnetic resonance (MR) urography and cystoscopy are the diagnostic tools to assess function, to detect reflux and to rule out ipsilateral compression of the lower pole and urethral obstruction. In the clarification of incontinence in girls, a methylene blue filling of the bladder can be helpful: in the case of loss of uncoloured urine, an ectopic ureter must be present.
Treatment
Ureterocele
The management is controversial with the choice between endoscopic decompression, partial nephroureterectomy or complete primary reconstruction. The choice of a therapeutic modality depends on the following criteria: clinical status of the patient (e.g., urosepsis), age of the patient, renal function of the upper pole, presence or absence of reflux, obstruction of the ipsilateral ureter, pathology of the contralateral ureter, and parents' and surgeon's preferences.
Early Diagnosis
- In a clinically asymptomatic child with an ureterocele and non- or hypo-functional upper pole, without significant obstruction of the lower pole and without bladder outlet obstruction, prophylactic antibiotic treatment is given until follow-up procedures are instigated
- In the presence of severe obstruction and infection, an immediate endoscopic incision or puncture is recommended
Re-evaluation
If decompression is effective and there is no reflux (approximately 25% of cases), the patient is followed-up conservatively. Secondary surgery is necessary if decompression is not effective, significant reflux is present or there is obstruction of the ipsi- or contra-lateral ureters and/or bladder neck obstruction. Surgery may vary from partial nephrectomy to complete unilateral reconstruction.
Ectopic Ureter
In the majority of cases, the upper pole is dysplastic and heminephro-ureterectomy should be considered. Ureteral reconstruction is a therapeutic option in cases in which the upper pole has function worth preserving.
