Vesicovaginal fistula in a dog with urinary incontinence.

Case Description: A 5-year-old spayed female Maltese mixed-breed dog was referred for evaluation because of severe urinary incontinence refractory to medical management.
Clinical Findings: Physical examination revealed constant dribbling of urine and urine scalding. Culture of a urine sample yielded methicillin-resistant Staphylococcus pseudintermedius and Proteus mirabilis . Abdominal ultrasonographic examination revealed absence of the left kidney, a small, nondistended urinary bladder, and diffuse hepatopathy. Urinary incontinence persisted despite appropriate antimicrobial treatment. Cystourethroscopy and vaginoscopy were subsequently performed and revealed a hypoplastic bladder and a vesicovaginal fistula with urinary leakage through the vaginal diverticulum; no left ureterovesicular junction was identified, consistent with suspected left renal aplasia.
Treatment and Outcome: Exploratory laparotomy was performed, and the cranial aspect of the vagina was circumferentially ligated immediately caudal to the fistula. The urinary incontinence resolved immediately after surgery, and lower urinary tract signs improved over the next 2 weeks. Moderate urinary incontinence recurred approximately 6 months later, and a urinary tract infection with Escherichia coli was subsequently identified and treated; clinical signs resolved ≤ 48 hours after treatment was initiated.
Clinical Relevance: To the author's knowledge, vesicovaginal fistulas in dogs have not been previously described and should be considered a differential diagnosis for persistent urinary incontinence and recurrent urinary tract infections in female dogs. Vaginoscopy in addition to cystourethroscopy was required to identify the abnormality in this patient. Because multiple concurrent anomalies can be present, both procedures should be performed in female dogs with these clinical signs, even if an abnormality is identified cystoscopically.