[Urinary incontinence in castrated bitches. 2. Diagnosis and treatment]

Urinary incontinence due to spaying is caused by a sphincter incompetence of the urethra. In practice the diagnosis is established by ruling out other causes of incontinence such as neurological disease, bacterial cystitis, urinary tract malformation, iatrogenic ureterovaginal fistula and neoplasia of the urinary tract. An accurate diagnosis of urethral sphincter incompetence is made by urethral pressure profilometry. A urethral closure pressure of 7.4 cm H2O allowed the differentiation of bitches with urinary incontinence, due to spaying, from healthy control dogs with a diagnostic accuracy of 91%. For therapy alpha-adrenergic drugs (Ephedrine or Phenylpropanolamine) are recommended, which result in continence in 74% and improvement in 24% of incontinent patients. In the absence of response estrogens may be used. If the medical therapy fails to achieve urinary continence, the endoscopic injection of collagen into the submucosa of the proximal urethra can be performed. This is a simple and minimally invasive procedure. It rarely leads to complications and may be repeated when necessary. The method is successful in 75% of cases.