Cath Lab Digest

Overactive bladder (OAB) is a symptom complex that comprises urinary urgency, with or without urge urinary incontinence (UUI), and often involves increased urinary frequency and nocturia.¹ Behavioral interventions and recent pharmacological advancements have offered symptom relief in many patients. Botulinum toxin (BTX) has provided an additional alternative in the treatment of refractory OAB.

Patient History and Diagnosis

Ms. M is a 62-year-old woman with severe complaints of urinary frequency, urgency, and rare urgency urinary incontinence. Her initial evaluation (history, physical examination [pelvic and neurologic], urinalysis, and post-void residual) was within normal limits. She also completed a voiding diary. She was started on behavioral and oral antimuscarinic therapy. She experienced no significant improvement in symptoms and subsequently underwent a complete lower urinary tract evaluation, including a cystoscopy and a pressure flow urodynamic study (PFUDS). She was found to have detrusor overactivity with urgency and urgency incontinence; the rest of the evaluation was unremarkable. Neurologic consultation ruled out a neurogenic cause for her symptoms.

Ms. M’s working diagnosis was idiopathic detrusor overactivity with urgency and urgency incontinence.

Treatment

Ms. M tried five different antimuscarinic medications and continued bladder training, biofeedback-assisted pelvic floor muscle training, and behavioral modifications including dietary changes with no significant improvement in her symptoms. Further discussion then was directed toward surgical intervention. She underwent a trial of sacral nerve stimulation with no improvement. When this failed, Ms. M was given the options of intradetrusor injections of botulinum-A toxin (BTX-A) or bladder augmentation. After a lengthy discussion, she decided to undergo BTX injection.

Ms. M tolerated the procedure well. She underwent the procedure as an outpatient with monitored anesthesia care in the operating room. After cystoscopy revealed a normal-appearing bladder mucosa, 300 units of BTX-A was injected into 30 different sites throughout the detrusor muscle of the bladder. She had excellent results. Her urinary frequency dramatically decreased and she had a complete resolution of her urinary urgency and urinary incontinence. Her last visit was 4 months post procedure and she continues to have a durable response. She plans to contact her physician when the efficacy of the treatment is significantly decreased and she wishes to repeat another injection course.

Discussion

This case study highlights the use of BTX, the most potent naturally occurring toxin known to man, in the treatment of refractory OAB. The potential lethal effects of BTX, most of which consist of some neuromuscular dysfunction, have been harnessed. The effects of BTX have been used for a number of medicinal purposes, including reducing wrinkles, migraine headaches, and excessive sweating. The use of BTX in urology and, more specifically, the lower urinary tract, is increasing. It is a treatment option under active study for use in neurogenic and non-neurogenic OAB, detrusor sphincter dyssynergia, interstitial cystitis, urinary retention, and prostate disorders.

BTX serotypes. The seven distinct serotypes of BTX are designated A, B, C1, E, F, and G; BTX-A (Botox [Allergan, Inc., Irvine, Calif] and Dysport [Ipsen, Inc., Europe]) and BTX-B (Myobloc (Solstice Neurosciences, Inc., Malvern, Pa) are available commercially. Each serotype of botulinum toxin works by inhibiting the release of neurotransmitters, most notably acetylcholine, from the presynaptic neuromuscular junction.² The result is inhibition of muscular contractions and paralysis.