Why might intermittent catheterization be needed after botulinum toxin A treatment for detrusor overactivity?

• A. To increase bladder contraction.
• B. To treat infections.
• C. To reduce urine production.
• D. To manage potential post-treatment urinary retention due to reduced detrusor contractility.

Answer: (D)

Botulinum toxin A relaxes the detrusor muscle by blocking acetylcholine release, which reduces detrusor overactivity and helps storage of urine. But this same relaxation can blunt the bladder’s ability to contract enough to empty fully, leading to urinary retention or a high post-void residual. When the bladder can’t evacuate urine adequately after voiding attempts, intermittent catheterization is used to drain the bladder, prevent overdistension, and protect kidney function. This may be temporary, resolving as the toxin wears off or detrusor function recovers. It’s not about increasing contraction or reducing urine production; it’s about ensuring complete emptying when voiding is insufficient after treatment.