Oxybutynin for diagnosis of infravesical obstruction in boys with urinary incontinence

To investigate whether good suppression of symptoms during anticholinergic therapy in boys with urinary urge incontinence is correlated with anatomic infravesical obstruction. In a prospective study, 65 boys with urge incontinence were treated temporarily with anticholinergics. The effect of therapy was assessed, and a full video-urodynamic evaluation was performed. When obstruction could not be excluded urodynamically, urethrocystoscopy was done to assess the level and severity of obstruction, followed by endoscopic treatment. The effect of oxybutynin on incontinence was compared with the presence or absence of obstruction. In 49 of 65 boys aged 4 to 14 years with daytime urge incontinence, infravesical obstruction was found. Of the 49 boys, 38 (76%) had a good response to anticholinergic therapy. Of the 16 boys without infravesical obstruction, 12 (75%) did not improve with anticholinergic therapy. When anticholinergic therapy was used as a diagnostic test for infravesical obstruction, we found a positive predictive value and negative predictive value of 90% (95% confidence interval 74% to 96%) and 52% (95% confidence interval 31% to 73%), respectively. The effect of anticholinergic therapy on urge incontinence can be used as a diagnostic test to differentiate between anatomic infravesical obstruction and other causes of incontinence in boys