Intravesical botulinum-A toxin in children with refractory non-neurogenic overactive bladder.

Introduction: Overactive bladder (OAB) with urinary incontinence poses a potentially significant impact on daily activities and quality of life. OAB can be unresponsive to specific urotherapy and antispasmodic medication. Due to its successful outcomes in the treatment of neurogenic bladder, intravesical botulinum-A toxin (BTX-A) became a possible solution for children refractory to treatment.

Objective: To analyse the outcomes of intravesical BTX-A injections on bladder volume and incontinence in children with refractory OAB.

Study Design: The charts of children diagnosed with refractory non-neurogenic OAB who underwent BTX-A treatment in our centre since 2011 were retrospectively analysed. The functional bladder volume (FBV) is expressed as a percentage of the expected bladder capacity (EBC) for age. Dependent variables were compared using the Wilcoxon Signed Rank test. A multivariate logistic regression was used to identify predictors of the response on urinary incontinence.

Results: Fifty children (41 boys) with a median age of 9.9 years were included. In the short term, there was a significant increase in FBV after initial BTX-A treatment from a median of 52.9%-70% (p = 0.000). In the short (<6 months) and long term (6-12 months) 72% and 46% showed improvement of continence, respectively. Male gender and small baseline FBV predict a positive outcome on continence in the long term. The most prevalent complications were urinary tract infections occurring in five cases (10%).

Discussion: Although BTX-A injections serve as an effective therapy to increase bladder volume in non-neurogenic OAB children, the outcomes on urinary incontinence are highly variable. This may be a consequence of the multifactorial aspects of this condition. BTX-A will enable children to inhibit their bladder urgency. The effectiveness of post-BTX-A urotherapy training will therefore most probably be higher. We believe that BTX-A injections should be reserved for children refractory to both specific urotherapy and medication. An appropriate population seems to be children with severe OAB symptoms, confirmed detrusor overactivity in urodynamic study and reduced bladder volume.

Conclusion: In refractory OAB children, BTX-A injections are safe and effective in enlarging bladder volume and reducing OAB symptoms, particularly in the first six months after injection.