Dr. med. Dirk Manski

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Ureterocele: Symptoms, Diagnosis and Treatment

Definition

The ureterocele is a cystic dilatation of the distal, intravesical ureter [fig. ureterocele cross-section and ureterocele in cystoscopy]. In 80%, the ureterocele drains the upper pole of a duplex kidney [fig. ureterocele with duplex kidney]. A ureterocele causes a defect in the trigonum and predisposes the patient to vesicoureteral reflux into the ureter of the lower pole of a duplex kidney. EAU guideline: Paediatric Urology.


Cross section through a ureterocele: cystic dilatation of the distal intravesical ureter.
figure Cross section through a ureterocele
Ureterocele in cystoscopy: bulging of the bladder mucosa with a stenotic ostium.
figure ureterocele in cystoscopy

The following classifications exist:

Ureteroceles are associated with ureteral duplication (in 80%); the ureterocele drains the upper pole of the duplex kidney.
figure Ureteroceles are associated with ureteral duplication

Epidemiology of Ureterocele

Prevalence 1:5000, more often in females (4:1).

Etiology of Ureterocele

Different theories exist, but no theory can explain all forms of ureteroceles:

Chwalla membrane:

The Chwalla membrane separates the urogenital sinus from the ureteral bud. A delayed and incomplete reabsorption of Chwalla membrane is postulated, causing a stenotic ostium which also leads to the cystic dilatation of the intravesical ureter. The theory does not explain the different sizes and forms of the ureterocele.

Disturbed Fusion of Wolffian Duct with the Urogenital Sinus:

The theory aligns the ureterocele with the ureterectopia: the more lateral the ureter bud, the later and more disturbed the fusion into the urogenital sinus.

Acquired ureteroceles:

Ostium stenosis (caused by inflammation, ureteral stone, or trauma) leads to a cystic dilatation of the distal ureter.

Signs and Symptoms of Ureterocele

Urinary tract infection, urosepsis, nephrolithiasis, ureterocele stone [ureterocele stone], abdominal tumor or failure to thrive in infants, prolapse from the urethra, urinary retention, hematuria, and incontinence.

Ureterocele stone: KUB plain film (left) and KUB after 12 min (right): right distal ureteral stone (arrow) without signs of obstruction. With kind permission, Dr. R. Gumpinger, Kempten.
figure i.v. urography with a right distal ureteral stone

Diagnosis of Ureterocele

The diagnostic workup is only necessary for patients with symptoms, suspected vesicoureteral reflux, or obstruction.

Ultrasound imaging:

Ureteroceles present as thin-walled cysts in the bladder [fig. ureterocele in TRUS]. For imaging, a medium-filled bladder is preferable. A ureterocele might cause urinary obstruction of the contralateral kidney. Ureteral duplication is often present, and a stenotic ostium of the ureterocele may cause hydronephrosis of the upper pole system.

Transrectal ultrasound imaging of a ureterocele (*) in the filled bladder (HB). In addition, an enlarged seminal vesicle (SB) is seen. With kind permission, Dr. med. H. Kempter, Augsburg.
figure Transrectal ultrasound imaging of a ureterocele

Intravenous urography:

The IVP often shows a poor visualization of the upper renal portion due to poor function; however, the upper part can contrast in late KUB. Hints for a non-contrasting upper pole are reduced chalices and a greater distance between the kidney system and the spine. The lower pole ureter is serpentine (around the upper pole ureter). Sometimes the ureterocele can be visualized in the bladder [fig. ureterocele causes filling defect]. The cystic dilatation of an uncomplicated intravesical ureterocele is called a cobra head sign.

Intravenous urography (left): right-sided ureterocele creates a filling defect in the urinary bladder, the associated upper pole chalices are not contrasted. Retrograde pyelography after incision of the ureterocele (right): the upper pole chalices show moderate signs of chronic hydronephrosis. With kind permission, Dr. R. Gumpinger, Kempten.
figure ureterocele causes filling defect in urography

Bilateral cobra head sign in intravenous urography: cystic dilatation of the distal ureters. With kind permission, Prof. Dr. R. Harzmann, Augsburg.
figure Bilateral cobra head sign in intravenous urography

Contrasted ureterocele in intravenous urography. With kind permission, Prof. Dr. R. Harzmann, Augsburg.
figure Clearly contrasted ureterocele in intravenous urography

Voiding cystourethrography:

The filling defect by the ureterocele shows size and location. Imaging the ureterocele is best during early filling; the ureterocele may collapse in a full bladder and present as a bladder diverticulum. Filling the bladder to full capacity is necessary to demonstrate reflux into the lower pole ureter, which is seen in duplex kidneys in up to 50%.

Cystoscopy:

See fig. ureterocele in cystoscopy.

Retrograde pyelography:

Before invasive treatment, see fig. retrograde pyelography before ureterocele incision.

Renal scintigraphy:

Renal scintigraphy evaluates renal function or the significance of hydronephrosis. If a duplex system is present, the renal function of the upper and lower pole must be analyzed separately.

Treatment of Ureterocele

A ureterocele without symptoms does not require therapy. The aim is to treat ureterocele with accompanying problems (prevent vesicoureteral reflux and UTI, relieve obstruction) with a single intervention, if possible.

Transurethral Ureterocele Incision:

Transurethral incision of the ureterocele is a treatment option with low morbidity [fig.~\ref{ureterozelenschlitzung}]. It is often curative for obstructive intravesical ureterocele with a single system or with a double system without severe reflux in the lower pole ureter. Extravesical ureteroceles are less likely to be healed by incision, never the less ureterocele incision is often performed as the first treatment attempt. If obstruction or severe postoperative reflux is a problem, ureteropyelostomy or ureteral reimplantation is necessary.

Transurethral incision of an intravesical ureterocele to enable treatment of multiple stones.
figure Transurethral incision of an intravesical ureterocele

Ureteropyelostomy:

Treatment option for an obstructive ureterocele (relapse after transurethral incision) of a duplex kidney without relevant reflux in the lower pole ureter. The upper pole ureter is anastomosed to the lower pole ureter (end-to-side). Surgery is possible with a flank incision or laparoscopically. The ureterocele should decompress spontaneously and thus reduce the reflux in the lower pole ureter. If postoperative vesicoureteral reflux is problematic, ureterocele resection and ureterocystoneostomy of the lower pole ureter are necessary.

Heminephrectomy for duplex kidneys with ureterocele:

Heminephrectomy is indicated for ureterocele and double system with poor upper pole function and without relevant reflux in the lower pole ureter. Surgery is possible with a flank incision or laparoscopically. The ureterocele should decompress spontaneously and thus reduce the reflux in the lower part. If postoperative vesicoureteral reflux is problematic, ureterocele resection and ureterocystoneostomy of the lower pole ureter are necessary.

Simultaneous reconstruction of the upper and lower urinary tract:

Simultaneous upper and lower urinary tract reconstruction may be necessary for ectopic ureterocele with severe reflux or obstruction of the contralateral kidney. Heminephrectomy or ureteropyelostomy is done via a flank incision, excision of the ureterocele, and ureteral reimplantation is performed via a separate incision for surgical access to the urinary bladder.





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References

EAU guidelines: Paediatric Urology

Shokeir und Nijman 2002 SHOKEIR, A. A. ; NIJMAN, R. J.: Ureterocele: an ongoing challenge in infancy and childhood.
In: BJU Int
90 (2002), Nr. 8, S. 777–83



  Deutsche Version: Diagnose und Therapie der Ureterozele