Ectopic Ureter

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Ectopic Ureter

Ectopic Ureter is a congenital anomaly of the urinary system. The ureteral orifice(s) is inappropriately positioned caudal to the bladder trigone (i.e., trigone, urethra, vagina, vestibule, uterus, or prostate), resulting in urinary incontinence.

  • A common cause of urinary incontinence in juvenile female dogs. Also seen in adult dogs.
  • Anomalous differentiation of the mesonephric and metanephric ducts resulting in inappropriate ureteral termination.
  • Dogs—> 95% tunnel intramurally, traversing the urethra in the submucosa.
  • Male dogs—most commonly associated with severe hydronephrosis and hydroureter due to ureteral opening stenosis.
  • Commonly associated with multiple anomalies of the urinary tract: > 75% have concurrent USMI, > 90% have PPMR, chronic UTIs (∼ 80%), hydroureter (35–50%), hydronephrosis (25–50%), short urethral/intrapelvic bladders (∼ 20%).

SIGNALMENT

  • Dog and cat.
  • Juvenile incontinent dogs (commonly).
  • Infrequently reported in cats and male dogs; 20:1 ratio of female:male dogs.
  • Dog breeds may be predisposed: retrievers, Siberian huskies, Newfoundlands, poodles, terriers.

 

SIGNS

  • Constant or intermittent incontinence since birth.
  • Normal voiding in some.
  • Chronic UTIs.
  • May be asymptomatic (male dogs) and can have moderate to severe hydroureter/hydronephrosis.

 

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS

  • USMI—urethral pressure profilometry.
  • Inappropriate urination—urge incontinence, “overactive bladder,” behavioral (conscious urination).
  • UTI—pollakiuria and urge incontinence.
  • Vaginal pooling—leakage after urination when patient stands up from recumbent position.
  • Congenital hydroureter/hydronephrosis—male dogs with EU often continent.
  • Short urethra/intrapelvic bladder syndrome.

 

CBC/BIOCHEMISTRY/URINALYSIS

Urine specific gravity and serum creatinine or urea nitrogen concentration often normal. Abnormal with concurrent anomalies (e.g., renal dysplasia, pyelonephritis).

 

OTHER LABORATORY TESTS

Urine bacterial culture and sensitivity—via cystocentesis.

 

IMAGING

  • Cystoscopy (96% sensitivity): diagnostic method of choice.
  • Helical computed tomography (91% sensitivity): more accurate than standard radiography.
  • Urinary tract ultrasonography (60–91% sensitivity) can provide accurate diagnosis and anatomical information of the upper urinary tract.
  • Excretory urography (50–75% sensitivity) with positive contrast cystogram or a pneumocystogram, followed by a vaginourethrogram (female) or urethrogram (male); may diagnose associated hydroureter/hydronephrosis, ureterocele, and/or absent or abnormal kidneys.
  • Retrograde urethrography (47% sensitivity).

 

DIAGNOSTIC PROCEDURES

  • Cystourethrovaginoscopy—definitive diagnosis of EU, short urethral syndrome, location of ectopic orifice in the genitourinary tract; identifies multiple fenestrations, troughs.
  • UPP—may detect concurrent USMI, but intramural ectopic ureter may confound results and therefore should not guide treatment of concurrent EU.

 

TREATMENT

  • Cystoscopic-guided laser ablation (CLA): performed for intramural EU only; simultaneous diagnosis and treatment; opens ureteral tract in a minimally invasive manner; addresses concurrent vaginal defects (∼ 95%).
  • Surgical: neoureterostomy (with or without distal tract dissection/reconstruction), reimplantation, or ureteronephrectomy; complication rates range between 14% and 25% including ureteral strictures, leakage, and infection.
  • Never consider ureteronephrectomy if ipsilateral renal function remains.
  • Warn owners that incontinence may continue in ∼ 45–70% of patients after surgery. Many patients become continent with the addition of medications, bulking agent augmentation, and/or placement of an artificial urethral sphincter.

 

MEDICATIONS

DRUG(S)

  • Use if incontinence persists after surgery.
  • Phenylpropanolamine: an α-blocker (1–1.5 mg/kg PO q8h) will improve continence after surgery/laser therapy in 10–20% of dogs, improving continence levels to 50–60%.
  • Diethylstilbestrol: initially 0.1–0.3 mg/kg q24h for 7 days, then once weekly; 0.1–1 mg PO for 3–5 days, then 1 mg per week thereafter. Gradually titrate to the lowest effective dose. DES is potentially toxic to the bone marrow and can cause blood dyscrasias. Estriol tablets: 2 mg once daily and then titrated to lowest effective dose. Combination of estrogen and PPA therapy may be more effective.
  • Testosterone propionate (2.2 mg/kg IM q2–3 days) or methyltestosterone (0.5 mg/kg/day) is administered to male dogs initially to see if replacement therapy will be effective. For longer action, testosterone cypionate (2.2 mg/kg IM q30 days) can be used.
  • Not advised in immature animals.
  • Estriol: can be used for estrogen-responsive urinary incontinence. The dose is 2 mg once daily per dog (regardless of body weight) for 14 days, followed by the lowest effective daily dose tapered every 7 days.

 

OTHER

After surgery/laser ablation (1) transurethral submucosal bulking agent injections: can improve continence to ∼60–65%; (2) placement of an artificial urethral sphincter (called a hydraulic occluder) can improve continence to ∼80–90%.

 

FOLLOW-UP

EXPECTED COURSE AND PROGNOSIS

  • Dogs—with surgery (25–50%) or laser ablation (40–55%) alone, continence rates range from 25% to 55%, which improves to 60% with medications, 65% with bulking-agent injection, and ∼80–90% with the placement of a hydraulic occluder.
  • Care should be taken in evaluation of hydroureter/hydronephrosis after surgery as ureteral strictures have been reported, which can result in permanent loss of the ipsilateral kidney.

 

MISCELLANEOUS

ASSOCIATED CONDITIONS

Hydronephrosis, hydroureter, ureterocele, pelvic bladder, persistent paramesonephric remnant, vaginal septum, renal dysplasia, renal agenesis, USMI, short urethra/intrapelvic bladder.

 

Visit your veterinarian as early recognition, diagnosis, and treatment are essential.

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