Ectopic ureter

From Dog
Excretory urogram of a young Newfoundland dog with urinary incontinence and recurrent cystitis due to bilateral ectopic ureters with marked secondary hydroureter[1]

Ectopic ureter (urethral ectopia) is a relatively common congenital ureteral disease of dogs characterized by a unilateral or bilateral misdirection of the ureter to the vagina or penile urethra.

This condition occurs in both male and female dogs, and may be unilateral or bilateral[2]. Concurrent ureteral atresia, renal agenesis and renal dysplasia also occur in association with ectopic ureters in dogs[3].

Some ectopic ureters attach abruptly to the urethra (extramural) while others tunnel within the connective tissue of the bladder trigone (intramural) before opening distally within the caudal urethra. The latter ureters are more difficult to treat due to secondary ureteral stenosis.

Affected dogs invariably present with chronic incontinence at a young age, although adult-onset incontinence has been observed with this condition[4].

In many dogs, a concurrent cystitis due to Escherichia coli is present due to retrograde infections from the urethra as a result of a poor urethral sphincter mechanism.

In severe cases, ascending infections, hydroureter and hydronephrosis may lead to chronic renal disease[5].

Diagnosis is usually confirmed by digital fluoroscopic excretory urography or computed tomography[6]. Excretory urography and ultrasonography are not as reliable for accurate diagnosis but have been used to establish a tentative diagnosis[7].

Visual confirmation can be achieved via cystoscopy[8] or exploratory laparotomy.

Although this is not a life-threatening condition, chronic renal disease is a common sequela and surgical correction is recommended.

A number of methods have been employed including neoureterostomy with resection restricted to the intravesical part of the ureter for intramural ectopic ureter or transurethral cystoscopic-guided laser ablation[9]. In cases where ureteral patency cannot be achieved with intramural ectopic ureters, a ureteronephrectomy may be considered as a salvage procedure[10].

For extramural ectopic ureters, a ureteroneocystostomy is often indicated[11], or use of a synthetic urethral sphincter[12].

Dogs with ectopic ureters that were incontinent postsurgically tended to remain unresolved, although phenylpropanolamine administration (1.75 mg/kg orally every 12 hours) may alleviate loss of urethral sphincter tone[13].

References

  1. Heuter KJ (2005) Excretory urography. Clin Tech Small Anim Pract 20(1):39-45
  2. Ho LK et al (2011) Clinical outcomes of surgically managed ectopic ureters in 33 dogs. J Am Anim Hosp Assoc 47(3):196-202
  3. Taney KG et al (2003) Bilateral ectopic ureters in a male dog with unilateral renal agenesis. J Am Vet Med Assoc 223(6):817-820
  4. Thomas PC & Yool DA (2010) Delayed-onset urinary incontinence in five female dogs with ectopic ureters. J Small Anim Pract 51(4):224-226
  5. Steffey MA & Brockman DJ (2004) Congenital ectopic ureters in a continent male dog and cat. J Am Vet Med Assoc 224(10):1607-1610
  6. Samii VF et al (2004) Digital fluoroscopic excretory urography, digital fluoroscopic urethrography, helical computed tomography, and cystoscopy in 24 dogs with suspected ureteral ectopia. J Vet Intern Med 18(3):271-281
  7. Oglesby PA & Carter A (2003) Ultrasonographic diagnosis of unilateral ectopic ureter in a Labrador dog. J S Afr Vet Assoc 74(3):84-86
  8. Holak P et al (2007) Applicability of endoscopic examination as a diagnostic approach in urinary tract ailments in dogs. Pol J Vet Sci 10(4):233-238
  9. Berent AC et al (2008) Use of cystoscopic-guided laser ablation for treatment of intramural ureteral ectopia in male dogs: four cases (2006-2007). J Am Vet Med Assoc 232(7):1026-1034
  10. Yoon HY et al (2010) Bilateral ureteral ectopia with renal dysplasia and urolithiasis in a dog. J Am Anim Hosp Assoc 46(3):209-214
  11. Reichler IM et al (2012) Ectopic ureters in dogs: clinical features, surgical techniques and outcome. Vet Surg 41(4):515-522
  12. Reeves L et al (2012) Outcome after Placement of an Artificial Urethral Sphincter in 27 Dogs. Vet Surg Nov 19
  13. Smith AL et al (2010) Cystoscopic diagnosis and treatment of ectopic ureters in female dogs: 16 cases (2005-2008). J Am Vet Med Assoc 237(2):191-195