Botulinum toxin A for the treatment of neurogenic detrusor overactivity in multiple sclerosis patients

Neurogenic detrusor overactivity (NDO) is common in patients who suffer from multiple sclerosis (MS). When the usual pharmacological treatment fails, botulinum toxin type A (BTX-A) injections can be proposed. The safety and efficacy of this treatment are already well known, but only a few studies focus on its use in patients with MS.

Seventy-one patients with MS underwent their first BTX-A injection for refractory NDO. They had clinical and urodynamic cystometry assessment before and three months after injection. The patients were divided in three groups according to treatment efficacy: full success (total urinary continence, no overactive detrusor), improvement, or total failure (urge incontinence and overactive detrusor).

77% of the patients had clinical improvement or full success of the treatment with a reduction of their urgency and incontinence. Significant urodynamic improvement after treatment was shown on different parameters: volume at first involuntary bladder contraction (p = 0.0000001), maximum cystometric capacity (p = 0.0035), maximum detrusor pressure (p = 0.0000001). 46% of the patients were in the "full success" group. 31% of the patients had a partial improvement. 23% of the patients had no efficacy of the treatment. Duration of MS was a predictive factor of treatment failure (p = 0.015).

Despite that a full success was obtained in 46% of the cases, BTX-A injection therapy failed to treat refractory NDO in 23% of patients suffering from MS. Duration of the disease was a predictive factor for an inefficient treatment. The injection therapy should be considered as soon as oral anti cholinergic drugs fail to reduce NDO.