[Injection of botulinum toxin (BTX-A) in children with bladder dysfunction due to detrusor overactivity].

INTRODUCTION: bladder dysfunction causes urinary incontinence and kidney damage in children. When treatment with anticholinergics and intermittent bladder catheterization fails, the alternative therapy is bladder augmentation.

PATIENTS AND METHODS: between 2005 and 2009, a prospective study was carried out with Botox(®) injected into the detrusor of children suffering from high-pressure bladder despite anticholinergic treatment. We assessed their urodynamic, clinical and radiological evolution prior to and at 4 weeks, 6 months and 1 year after the injection (10 u/kg of weight up to 300 u). Reinjection was indicated in the event of clinical or urodynamic worsening. We employed the Wilcoxom test to statistically analyze the urodynamic parameters.

RESULTS: 12 patients were treated, 11 with neurogenic bladder (91.7%) and 1 with posterior urethral valves (8.4%). The mean age was 12.6 (4.3-17.8) years and follow-up took place after 40.8 (16.9-45-7) months. Bladder capacity, detrusor accommodation and pressure improved after 4 weeks in all the patients except in 2 (16.7%). This improvement decreased after 6 months, although successive injections produced similar changes. One patient (8.3%) received 1 dose, six (50%) two doses and five (41.7%) received three. Clinical and urodynamic improvement in 8 patients (66.7%) prevented bladder augmentation.

CONCLUSIONS: repeated botulinum toxin injection in the detrusor is a therapeutic instrument for high pressure and low accommodation bladders in children. It could replace bladder augmentation in some cases, however further studies with long-term follow-up care are required to appropriately evaluate its safety and effectiveness.