Repeated botulinum-A toxin injections in the treatment of myelodysplastic children and patients with spinal cord injuries with neurogenic bladder dysfunction

Authors from Germany describe the use of botulinum toxin in the treatment of myelodysplastic children and found it to be safe and effective. They found that repeat treatments are as effective as the first one, with no evidence of tachyphylaxis, antibody formation or detrusor fibrosis. To examine the effects of repeated detrusor injections of botulinum-A toxin (BTX) for possible changes in bladder function, muscular structure of the detrusor, increase in BTX tolerance (tachyphylaxis) and side-effects, as BTX is a new treatment alternative for patients with a neurogenic bladder condition that is difficult to treat and refractory to anticholinergic medication. Between 2000 and 2005, 19 patients with myelodysplasia (MDP) and 25 spinal cord-injured (SCI) patients were treated with repeated suburothelial BTX injections (Dysport (R), Ipsen-Pharma, Ettlingen, Germany) or injections into the intramural detrusor. The follow-up was >= 3 years (range 3-5, median 4.5). Detrusor compliance, bladder capacity, and detrusor pressure at maximum filling improved significantly (P < 0.001) compared to baseline after each BTX injection. There was prolonged efficacy of each BTX administration and all repeated injections in the paediatric and adult patients with neurogenic bladder dysfunction over a median follow-up of 4.5 years. There was no evidence for drug tolerance or changes in the morphological appearance of the bladder. Safety was good: no complications were associated with the injection procedure itself. Early in the treatment programme, three patients who received a dose of 1000 units Dysport showed systemic side-effects and generalized muscle weakness. These resolved without intervention and did not recur after reducing the adult dose to 750 units (paediatric dose 20 units/kg, not > 400 units), which seems to be the optimum for good efficacy with an adequate safety margin. BTX injection is a safe and effective treatment for neurogenic detrusor hyperreflexia. Repeat treatments are as effective as the first: there was no indication of a lack of efficacy due to tachyphylaxis, antibody formation, or fibrosis of the detrusor muscle in this sample.