Simultaneous cystometry and uroflowmetry for evaluation of micturition in two dogs.

A recently developed urodynamic testing procedure was used to evaluate disorders of micturition in 2 dogs. The procedure simultaneously recorded intravesical pressure and urine flow during micturition. In an 11-year-old spayed female Sheltie that could not urinate normally, a micturition study demonstrated functional outflow obstruction of the urinary bladder. Although the urethra was patent, the urethral resistance factor, as calculated from pressure and flow data, was extremely high during voiding efforts. A urethral transitional cell carcinoma along with secondary infection, inflammation, and fibrosis were found to be responsible for the dog's problem. Ability to urinate was restored following removal of the affected portion of the urethra. In a 6-year-old spayed female Doberman Pinscher with urinary incontinence during sleep, a micturition study demonstrated urethral incompetence. During infusion of 0.9% NaCl solution into the bladder, the fluid flowed through the urethra before the detrusor muscle contracted, and urethral resistance during voiding was low. The dog's incontinence was responsive to estrogen administration.