Congenital urethral sphincter mechanism incompetence: observational clinical findings and treatment outcomes-a small retrospective study in 19 bitches.

BACKGROUND: This study aimed to report observational clinical findings and treatment outcomes in a population of bitches affected with congenital urethral sphincter mechanism incompetence (CUSMI). Response rate to sympaticomimetic drugs has not yet been reported in the literature in dogs affected with CUSMI. Juvenile bitches showing clinical signs of urinary incontinence were included. A diagnosis of CUSMI was made based on history, clinical signs, confirmation of orthotopic ureters and urethral pressure profilometry. At first consultation, all bitches (neutered or not) received phenylpropanolamine 1.5 mg/kg orally Semel in Die for at least one month. Median short-term (32 days) and long-term (38.7 months) follow-up data were collected via physical recheck, telephone or email questionnaire with owners, to include continence scores. RESULTS: Nineteen bitches met the inclusion criteria. At the time of diagnosis, there was no significant difference of continence score between neutered and non-neutered bitches (P = 0.14). During the course of the study, 17 out of 19 bitches were neutered: nine were neutered before the first heat (before heat group) and eight after the first heat (after heat group). Two bitches were non neutered at long term follow-up. After phenylpropanolamine treatment, continence score was not significantly different between the two groups (P = 0.71) with a median continence score of 4 (2-5) for the before heat group and a median continence score of 4 (3-5) for the after heat group. 26% of bitches (5/19) were fully continent after phenylpropanolamine treatment at short term follow-up. Continence score after treatment (median = 4 [2-5]) was significantly higher than continence score at diagnosis (median = 2 [1-4]) (P < 0.001). In the after heat group, temporary improvement of continence scores was observed before or during estrus in three out of eight dogs. Worsening of continence score was reported after neutering in 5/17 dogs. At long-term follow-up, 6/19 dogs were fully continent, 5 of them receiving additional treatment. CONCLUSION: Based on the results of this retrospective study, CUSMI may show a low rate of initial complete response achieving full continence status after phenylpropanolamine treatment at 1.5 mg/kg SID orally when compared to treatment of acquired urethral sphincter mechanism incompetence patients. Observational clinical findings suggest that worsening of incontinence may possibly occur after neutering including dogs that experienced improvement before or during estrus.