Bladder problems
Ectopic Ureter in dogs

Ectopic means the abnormal location of a structure, in this case the ureter, the long narrow duct that conveys urine from the kidney to the urinary bladder.  It occurs most commonly in the bitch, but both male ad female dogs and cats may be affected.  The defect is most commonly reported in 3 -6 months old dogs of which females are 8 times more frequently affected than males.  It is the commonest cause of urinary incontinence in juvenile dogs.  There is a familial occurrence in the Siberian Husky, but it also frequently occurs in the French Toy Poodle, Labrador, Scottish Terriers and Newfoundland.

Ectopic ureter results from the abnormal differentiation of the metanephric duct system.  The metanepehric ducts are the slender tubular portions of the embryonic metanephric diverticulum that later forms the ureters.  The ureters normally terminate in the vesico-ureteral area of the bladder to form the trigone area of the urinary bladder.  An ectopic ureter may open in the uterine body, bladder neck, urethra, the vagina in the female, or in the ductus deferens of the male animal.  Ectopic ureters may occur uni- or bilaterally.  It occurs bilaterally in approximately 25% of cases.  Other abnormalities that are frequently associated with ectopic ureter include:  hydroutereter (distension of the ureter with urine due to blockage); hydronephrosis (swelling of the kidney(s) when urinary flow is obstructed in any part of the urinary tract); renal hypoplasia (incomplete development or underdevelopment of the kidney(s); bladder hypoplasia; and urethral sphincter incompetence (incomplete closure of the urethral sphincter resulting in leakage of urine).

Urinary incontinence since birth is the most frequent clinical sign, especially in the bitch.  Sometimes the incontinence may however only be noticed for the first time at weaning.  In male dogs, urinary incontinence is usually first noticed when they are 10 to 12 months of age.  Dribbling of urine is constant and as a result the hair surrounding the vulva remains wet, discoloured and has a bad odour.  Affected bitches often urinate normally despite the constant dribbling of urine.  Affected animals are usually otherwise healthy, although cystitis (inflammation of the urinary bladder) or pyelonephritis (inflammation of the kidney and upper urinary tract) can easily develop if urinary tract infection is present.

Contrast radiography.

• Excitement in young animals.
• Neurogenic disorders (disorders originating in the nerves or nervous tissue)
• Cystitis and/or urethritis (inflammation of the urethra)
• Bladdeer sphincter incompetence in the bitch
• Partial urethral obstruction due to urinary calculi (mineral deposits)
• Hormonal imbalances following ovario-hysterectomy (sterilization)
• Neoplasia of the bladder neck
• Other congenital abnormalities

Surgical correction.

The prognosis is guarded if the ectopic ureter terminates in the vagina or the urterus.  Regardless of the surgical technique used, the prognosis is even poorer when the ectopic ureter terminates in the urethra, because the condition is associated with a higher degree of post-operative incontinence.

Veterinary articles supplied by Dr S Strydom and published with kind permission of DIA Publishing - publishers of KUSA Dogs in Africa Magazine

Dr Sunelle Strydom qualified as a veterinarian in 2004 at the Faculty of Veterinary Science, University of Pretoria.  She has a passion for writing and the sharing of knowledge to promote animal health and welfare.  She has written several articles for KUSA Dogs in Africa as well as for Vra vir Faffa on the Landbouweekblad website at www.landbou.com