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• Congenital Renal and Genitourinary Anomalies
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Ureteral anomalies frequently occur with renal anomalies but may occur independently. Complications include

• Obstruction, infection, and calculus formation (due to urinary stasis)
• Urinary incontinence (due to abnormal termination of the ureter in the urethra, perineum, or vagina)

Diagnosis may be suggested by abnormalities on routine prenatal ultrasonography (eg, hydronephrosis) and occasionally by physical examination (eg, finding an external ectopic ureteral orifice). However, many anomalies are first suspected when children develop UTIs. Ureteral anomalies should be suspected in children with an episode of pyelonephritis or children with recurrent UTIs. Testing typically involves ultrasonography of the kidneys, ureters, and bladder before and after voiding, and then voiding cystourethrography.

Treatments are surgical.

Duplication anomalies: Partial or complete duplication of one or both ureters may occur with duplication of the ipsilateral renal pelvis. The ureter from the upper pole of the kidney opens at a more caudal location than the orifice of the lower pole ureter. Ectopia or stenosis of one or both orifices, vesicoureteral reflux into the lower ureter or both ureters, and ureterocele may occur. Surgery may be necessary if there is obstruction, vesicoureteral reflux, or urinary incontinence.

Ectopic orifices: Openings of single or duplicated ureters may be malpositioned on the lateral bladder wall, distally along the trigone, in the bladder neck, in the female urethra distal to the sphincter (leading to continuous incontinence despite a normal voiding pattern), in the genital system (prostate and seminal vesicle in the male, uterus or vagina in the female), or externally. Lateral ectopic orifices frequently lead to vesicoureteral reflux, whereas distal ectopic orifices more often cause obstruction and incontinence. Surgery is needed for obstruction and incontinence and sometimes for vesicoureteral reflux.

Retrocaval ureter: Anomalous development of the vena cava (pre-ureteric vena cava) allows the infrarenal vena cava to form anterior to the ureter (usually the right); a retrocaval ureter on the left occurs only with persistence of the left cardinal vein system or with complete situs inversus. Retrocaval ureter can cause ureteral obstruction. For significant ureteral obstruction, the ureter is surgically divided with uretero-ureteral anastomosis anterior to the vena cava or iliac vessel.

Stenosis: Narrowing may occur at any location in the ureter, most frequently at the ureteropelvic junction and less commonly at the ureterovesical junction (primary megaureter). Consequences include infection, hematuria, and obstruction. Stenoses often diminish as the child grows.

In primary megaureter, ureteral tapering and reimplantation may be needed when dilation increases or infection or obstruction occurs. In ureteropelvic junction obstruction, pyeloplasty (excision of the obstructed segment and reanastomosis) may be done by open, laparoscopic, or robotic techniques.

Ureterocele: Prolapse of the lower end of the ureter into the bladder with pinpoint obstruction may cause progressive ureterectasis, hydronephrosis, infection, occasional calculus formation, and impaired renal function. Treatment options include endoscopic transurethral incision and open repair.

When a ureterocele involves the upper pole of duplex ureters, treatment depends on function in that renal segment, because of the significant incidence of renal dysplasia. Removal of the affected renal segment and ureter may be preferable to obstruction repair if no segmental renal function is found or if significant renal dysplasia is suspected.

Vesicoureteral Reflux

Vesicoureteral reflux (VUR) is retrograde passage of urine from the bladder back into the ureter and collecting system.

Etiology

VUR is most often due to congenital anomalous development of the ureterovesical junction. Incomplete development of the intramural ureteral tunnel causes failure of the normal flap valve mechanism at the ureterovesical junction that permits reflux of bladder urine into the ureter and renal pelvis. Reflux can occur even when the tunnel is ordinarily sufficient if bladder outlet obstruction increases intravesical pressures.

Pathophysiology

Reflux of urine from the bladder into the ureter may damage the upper urinary tract by bacterial infection and occasionally by increased hydrostatic pressure. Bacteria in the lower urinary tract can easily be transmitted by reflux to the upper tract, leading to recurrent parenchymal infection with potential scarring and renal dysfunction. VUR is a common cause of UTI in children; about 30 to 40% of infants and toddlers with UTI have VUR.

Chronically elevated emptying pressures (> 40 cm H₂O) and increased bladder volume and pressure often cause progressive kidney damage, even without infection or reflux.

Symptoms and Signs

Symptoms and signs are typically those of UTI; these may include fever, abdominal or flank pain, dysuria or flank pain with voiding, frequency, and urgency.

Diagnosis

• Ultrasonography
• Voiding cystourethrography
• Sometimes radioisotope scan

Urinalysis and culture are done to detect infection; pyuria, hematuria, proteinuria, and bacteriuria may be present.

Children typically should have ultrasonography of the kidneys, ureters, and bladder before and after voiding, and then voiding cystourethrography. Renal ultrasonography evaluates kidneys for size, hydronephrosis, and scarring, and voiding cystourethrography is best to diagnose bladder outlet obstruction. A radioisotope cystogram may be used to monitor reflux. Renal cortical involvement with acute infection or scarring is precisely delineated with succimerSome Trade Names
CHEMET
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(dimercaptosuccinic acid) nuclear scans when indicated. Urodynamic studies may show elevated filling and voiding pressures in the bladder.

Reflux findings on voiding cystourethrogram are graded on a scale from I to V (see Table 1: Miscellaneous Infections in Infants and Children: Grades of Vesicoureteral Reflux*). Clinical severity can be classified based on reflux severity. However, the grades of reflux can be affected by bladder capacity.

• Mild: Grades I and II
• Moderate: Grade III
• Severe: Grades IV and V

Treatment

• Antibiotic prophylaxis
• Sometimes injection of a bulking agent or ureteral reimplantation

Mild to moderate VUR often resolves spontaneously over months to several years while daily antibacterial prophylaxis (eg, with trimethoprim/sulfamethoxazoleSome Trade Names
BACTRIM
SEPTRA
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, amoxicillinSome Trade Names
AMOXIL
TRIMOX
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, nitrofurantoinSome Trade Names
FURADANTIN
MACROBID
MACRODANTIN
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, a cephalosporin, or sulfisoxazoleSome Trade Names
GANTRISIN

) is maintained; it is very important to keep children free of infection.

Severe reflux accompanied by high-pressure storage of urine in the bladder or high intravesical pressures with voiding is treated by lowering bladder pressures with drugs (eg, oxybutyninSome Trade Names
DITROPAN
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), behavioral modification using perineal electromyography, or both.

Reflux with complications (eg, infection, impaired renal growth, renal scarring) is treated with endoscopic subtrigonal injection of a bulking agent (eg, dextranomer/hyaluronic acid) or ureteral reimplantation. Obstruction is also surgically repaired.

Monitoring: Reflux is monitored by voiding cystourethrography or radioisotope cystography every 1 or 2 yr depending on severity of the reflux.

Renal growth is monitored by annual ultrasonography until age 5, then every other year until spontaneous resolution or for 3 yr after surgical correction.

Last full review/revision January 2010 by Ronald Rabinowitz, MD

Content last modified January 2010