Bladder, Urethra and Ureters

Ectopic ureters

Rather than inserting into the bladder, ectopic ureters insert into other parts of the urinary tract. Most insert distal to the trigone and empty urine into the vaginal vault. Ectopic ureters in horses are unilateral in 75% of the cases and bilateral 25% of the time. Ectopic ureters have been diagnosed in camelids and are treated with unilateral nephrectomy.

Clinical signs typically include urine scalding from birth, particularly in fillies. Normal urination is possible if the animal has unilateral ectopia or if the bladder fills due to urethrovesicular reflex (backwards flow). Colts may not be incontinent since retrograde filling of bladder will often occur.

Diagnosis is confirmed by a combination of  contrast studies, ultrasound and endoscopy. Intravenous urography doesn’t usually work well due to dilution of the contrast media in horses (just can’t see it). Retrograde urethrocystography is performed by inserting a balloon tipped catheter into the bladder and infusing enough media to distend the bladder and hopefully fill up the ureters.  Injection of contrast directly into the renal pelvis, creating an excretory urogram, was successful in a case seen at the UMN.  Ultrasound may identify dilated ureters and/or a dilated renal pelvis. Using videoendoscopy, the ureters can be watched for urine flow. A papilla may be seen in the vagina that is the exit site of the ectopic ureter. Colored dyes may also be given orally that change urine color, making the ectopic site more readily identified. 

  • indigoermine 0.25 mg/kg
  • phenolsulfonphthalein 0.01 mg/kg
  • sodium fluorescein 11 mg/kg
  • neoprontosil 0.05 ml/kg

It is important to evaluate for hydroureter and hydronephrosis as either will affect treatment and/or prognosis.

Treatment of ectopic ureters is by either ureterovesical anastomosis (as performed in small animals) or nephrectomy. Nephrectomy is recommended for unilaterally ectopic ureters; obviously this doesn’t work well for bilateral cases. Early treatment decreases the risk of hydronephrosis and ascending infection.


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Large Animal Surgery - Supplemental Notes Copyright © by Erin Malone, DVM, PhD is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.