A 28 month old spayed female Swiss Mountain Dog was presented to the Cornell University Small Animal Medicine service with history of urinary incontinence beginning at 15 months of age, a month after her ovariohysterectomy. Her owners reported that the dog was difficult to housebreak and had frequently urinated in the house as a puppy but was housebroken and continent for at least three months prior to her ovariohysterectomy. Two months prior to presentation she was diagnosed with and successfully treated for a urinary tract infection. Her referring veterinarian had presumptively diagnosed her with urinary sphincter mechanism incompetence and treated her with phenylpropanolamine (Proin®) and diethylstilbestrol with only intermittent relief. She was referred to Cornell for further diagnostic evaluation of her incontinence. On physical examination her vital parameters were within normal limits and no neurologic or other abnormalities were detected. A complete blood count, serum chemistry, urinalysis, and urine culture and sensitivity were performed with no significant abnormalities detected. A haired, freely movable, dermal mass was found on her left dorsal neck, aspirated and diagnosed as a mast cell tumor which was surgically managed by the Cornell University Small Animal Surgery service.
The history and the results of the initial diagnostics, and neurologic examination suggested that the cause of the incontinence was either anatomical (ectopic ureter(s), vaginal strictures, urovaginal fistula, or urethrorectal fistula) or functional (urinary sphincter mechanism incompetence). In order to rule out some anatomicl causes of incontinence a full abdominal ultrasound, digital vaginal examination, and cystography were performed.