Congenital Ureteral Anomalies

•Complete ureteral duplication:

–This results from an accessory ureteral bud.

–Complete duplication occurs when two separate ureteric buds arise from a single Wolffian duct.

–According to the Weigert-Meyer rule, the future lower pole ureter separates from Wolffian duct earlier and thus migrates superiorly and laterally as the urogenital sinus grows.

–The result is complete duplication, with the upper ureter usually protruding into the bladder more medially and inferiorly than the lower ureter.

•Ectopic termination of a single system or of the ureter of a duplex system is the result of the high (cranial) origin of the ureteral bud from the mesonephric duct.

•Ectopic ureter:

–This results from delayed incorporation of the ureteral bud into the bladder.

–The resulting position of the ureteral orifice is more caudal and medial or in more severe cases it inserts into one of the Wolffian duct structures.

•The ureters are paired muscular tubes that run from the renal pelvis to the bladder.

•The ureters run through three natural areas of narrowing:

–The ureteropelvic junction

–The crossing of the iliac vessels

–The ureterovesical junction (UVJ)

•The UVJ may be divided into three sections:

–The terminal portion (juxta vesical ureter)

–The intramural portion

–The submucosal portion (under the bladder mucosa).

•The function of the ureter is to effectively transport the urinary bolus from the minor calyces to the urinary bladder at acceptably low pressures.

•The efficiency of this function depends on adequate coaptation of the ureteral wall to propel the urinary bolus.

•If the ureter fails to propagate the peristaltic wave, the static urine distends the upper urinary tract and reduces luminal coaptation.

•Other factors that may affect ureteral transport include urinary volume and bladder pressure.

6.2Clinical Features

•The clinical presentations of ureteral anomalies are variable and the majority are asymptomatic.

•There are no specific clinical signs associated with ureteral anomalies.

•The diagnosis is sometimes suspected on routine prenatal ultrasound.

•Some patients present with UTI, abdominal mass or hematuria.

•Children with primary mega ureters may also present with cyclic abdominal pain/flank pain, or, less commonly, acute pain crisis.

•Patients may present with a cystic mass at the urethral meatus representing a prolapsed ureterocele.

•In other patients, the diagnosis is incidental after imaging studies for unrelated symptomatology.

•Ureteral anomalies may be discovered during the evaluation of a patient with:

–Hypertension

–Proteinuria

–Renal insufficiency in rare cases of severe bilateral anomalies

•Approximately 50 % of females with ectopic ureters present with constant urinary incontinence or vaginal discharge.

•In males, incontinence is never due to an ectopic ureter because the ectopic ureter never inserts distal to the external urethral sphincter.

•Rarely, an ectopic ureteral insertion may present with recurrent epididymitis in pepubertal boys.

•Post pubertal males with ectopic ureters most commonly present with chronic prostatitis and painful intercourse and ejaculation.

6.3Investigations and Diagnosis

•Urinalysis and urine culture are important in children presenting with unexplained fever.

•The diagnosis of UTI should prompt further radiological evaluation to identify urological anomalies.