Rosenfeld DL, Preston MP, Salvaggi Fadden K.

Serial renal sonographic evaluation of patients with Lesch-Nyhan syndrome. Pediatr Radiol 1994; 24: 509-512.

Schultz-Lampel D, Lampel A, Lazica M, Thiiroff JW.

Extrakorporale Stosswellenlithotripsie im Kindesalter. Urologe A 1997; 36: 200-208.

Shroff S, Watson GM.

Experience with ureteroscopy in children. Br J Urol 1995; 75: 395-400.

Stapleton FB.

What is the appropriate evaluation and therapy for children with hypercalciuria and hematuria? Semin Nephrol 1998; 18: 359-360.

Van Horn AC, Hollander JB, Kass EJ.

First and second generation lithotripsy in children: results, comparison and followup. JUrol1995; 153:1969-1971.

OBSTRUCTIVE PATHOLOGY OF RENAL DUPLICATION: URETEROCELE AND ECTOPIC URETER

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 at birth by physical examination, radiography and, occasionally, cystoscopy. In other cases, for example in adults, these anomalies are revealed by clinical symptoms: UTI, 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 dolichomegaureter. In the caecoureterocele, the upper pole of the renal duplication is always dysplastic and non-functional.

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, 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 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 small, 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:

1. At birth, a prolapsed and sometimes strangulated ureterocele may be observed in front of the urethral
orifice. In a neonate boy, it might cause acute urinary retention, simulating urethral valves.

2. The early symptom of pyelonephritis in either sex may lead to the diagnosis.

3. 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 excretory urography and/or nuclear renography in the region of interest. Urography might visualize the morphological status of the upper pole and lower moieties and of the contralateral kidney. A VCUG is mandatory in identifying an ipsilateral or contralateral reflux and to assess the degree of intraurethral prolapse of the ureterocele.

When the differential diagnosis between ureterocele and ectopic megaureter is difficult, urethrocystoscopy might reveal the pathology.

Ectopic ureter

Most of the ectopic megaureters are diagnosed primarily by ultrasound. In some cases, clinical symptoms can lead to diagnosis:

1. In neonates: pyuria and acute pyelonephritis.

2. In older girls: dribbling incontinence with concurrent normal micturition is characteristic. In such cases,
the ectopic orifice may be found in the meatal region. Significant fluor vaginalis may be the equivalent of
incontinence in little girls.

3. In pre-adolescent males: epididymitis is the usual clinical presentation and a palpable seminal vesicle
may be found on digital rectal examination.

Ultrasonography, excretory urography, nuclear studies, VCUG and cystoscopy are the diagnostic tools to assess the 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 case of loss of uncoloured urine, an ectopic ureter must be present. It is rarely necessary to perform a CT scan to find a small upper pole moiety invisible on IVU or by sonography.

TREATMENT

Ureterocele

The management is controversial between endoscopic decompression, partial nephro-ureterectomy 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 and pathology of the contralateral ureter.

Early diagnosis

1. In a clinically asymptomatic child with an ureterocele and non- or hypofunctional upper pole, without
significant obstruction of the lower pole and without bladder outlet obstruction, a prophylactic antibiotic
treatment is given for 3 months until surgery is performed.

2. In the presence of obstruction of the lower pole ureter or of the contralateral ureter, or urethral
obstruction, an immediate endoscopic incision or punction is recommended in combination with
prophylactic antibiotic treatment. After 3 months a re-evaluation is performed.

Re-evaluation: If decompression is effective and there is no reflux (approximately 25%), medical treatment is stopped and follow-up is based on urine cultures and ultrasound. If decompression is not effective or significant reflux is present or obstruction of the ipsi- or contralateral ureters and/or bladder neck obstruction, secondary surgery is necessary varying from partial nephrectomy to complete unilateral reconstruction (depending on upper pole function).

Late diagnosis

1. Non-functional upper pole, no further pathology: heminephro-ureterectomy is the method of choice.

2. Presence of significant reflux or obstruction: excision of the ureterocele and re-implantation of the
ureter/ureters, heminephro-ureterectomy according to the function of the upper pole.

Bladder outlet obstruction caused by ureterocele: endoscopic incision might be an optional therapy, with awareness of secondary surgery in the majority of the patients.

Ectopic ureter

In the majority of cases, the upper pole is dysplatic and requires heminephro-ureterectomy. For the exceptional case in which the upper pole has function worth preserving, ureteral re-implantation into the bladder or uereteropyelostomy in combination with partial ureterectomy are therapeutic options.

9.5 REFERENCES Ureterocele