What is botulinum toxin and how does it treat urinary incontinence?
Botulinum toxin treatments are best known as a type of cosmetic injection. For aesthetic indications like the treatment of dynamic facial wrinkles, toxins like Botox treat these wrinkles in order to counteract the effects of aging. However, that is not all that botulinum toxins can do. Botox is a highly versatile injectable, and this is due in part to its ability to relax treated muscles and prevent them from contracting. This mechanism of action makes Botox very useful in the treatment of movement and neuromuscular disorders; certain pain-associated disorders, such as chronic migraines; and certain bladder dysfunctions.
When treating an overactive bladder or detrusor overactivity associated with a neurologic condition, Botox is injected into the detrusor, the muscle in the bladder wall, to prevent hyperactivity.
Which patients are not good candidates for Botox treatment?
Patients that have an existing medical condition that may impede on neuromuscular function-such as myasthenia gravis, Eaton-Lambert syndrome, or amyotrophic lateral sclerosis-should not receive Botox treatment. Additionally, female patients who are expecting or nursing should be excluded from treatment. Finally, patients who currently have a urinary tract infection (UTI) or are not able to empty their bladder on their own (and are not routinely catheterizing) should not receive Botox injections for their bladder dysfunction.
Administration of Botox: professionals
For these purposes, Botox is administered to the detrusor muscle via cystoscopy. Botox is supplied in the form of a white lyophilized powder that will have to be reconstituted prior to use. To reconstitute Botox, the following steps are recommended:
• The diluent of choice is sterile, preservative-free 0.9% sodium chloride Injection, USP.
• Determine the appropriate dose. For an overactive bladder, the recommended dilution is 100 units/10ml; for detrusor overactivity associated with a neurologic condition, the recommended dilution is 200 units/30 ml. Draw up the suitable amount of diluent in an appropriately-sized syringe, and slowly dispense the diluent into the vial by injection. Gently mix by rotating the vial.
• Store the reconstituted solution in a refrigerator (2-8°C). Administer the solution within 24 hours after reconstitution.
The following are considerations and precautions of treating bladder dysfunction with Botox injections:
• Prior to treatment, start the patient on a course of prophylactic antibiotics that excludes aminoglycosides three days before treatment and extends this course to one to three days post-treatment. This is to minimize the risk of contracting a urinary tract infection.
• If the patient is receiving anti-platelet therapy, they should stop taking the medication at least three days before the injection procedure. These patients should be managed with caution to prevent excessive bleeding.
• Choice of anesthesia comprises either the intravesical instillation of diluted local anaesthetic with or without sedation, or general anaesthesia. If a local anesthetic instillation is used, the bladder should be drained and irrigated with saline before injection.
• Prior to the cystoscopy procedure, instil the bladder with saline with an amount sufficient for visualization but not enough to cause overdistension.
• Prime the needle with 1ml of reconstituted Botox before the start of injections to remove any air.
To administer Botox for the treatment of an overactive bladder, do the following:
• Inject reconstituted Botox solution into the detrusor muscle in 20 injections of 0.5ml each for a total volume of 10ml. Injection should be achieved via a rigid or flexible cystoscope. Be sure to avoid the trigone when injecting.
• The needle should be injected about 2mm into the detrusor.
• Once the procedure is complete, the patient should be observed for 30 minutes and should be released only once they have demonstrated their ability to adequately discharge urine.
To administer Botox for the treatment of detrusor overactivity associated with a neurologic condition, do the following:
• Inject reconstituted Botox solution into the detrusor muscle while avoiding the trigone. The injection regimen entails a total of 30 injections of 1ml each for a total volume of 30ml. Injection should be achieved via a rigid or flexible cystoscope.
• The needle should be inserted approximately 2mm into the detrusor.
• Upon completion of the procedure, drain the bladder of the saline used for visualization. The patient should be then observed for half an hour.
What are the complications that can potentially develop as a result of Botox treatment?
After treatment, Botox will start to take effect after about two weeks, and patients should plan for repeat treatments about every six months but no sooner than three months from the preceding treatment. The side effects associated with Botox treatment for overactive bladder are mild and minimal. They can include dysuria (pain during urination), urinary tract infection, and temporary urinary retention (inability to empty the bladder spontaneously).
Botox has a wide variety of therapeutic indications, including the management of symptoms of certain types of bladder dysfunction. If you think you could benefit from Botox for incontinence, talk to your doctor about treatment options.