Overactive Bladder - Treatment

Treatment of overactive bladder is primarily aimed at restoring lost control of the bladder's storage function. For all forms of overactive bladder, the main treatment method is medication. The standard drugs of choice are anticholinergics (m-anticholinergics). As a rule, medication is combined with behavioral therapy, biofeedback, or neuromodulation. The mechanism of action of anticholinergic drugs is to block postsynaptic (m2, m1) muscarinic cholinergic receptors of the detrusor. This reduces or prevents the effect of acetylcholine on the detrusor, reducing its hyperactivity and increasing bladder capacity.

Until recently, treatment of overactive bladder consisted of oxybutynin (driptan). The maximum dose of the drug is usually 5-10 mg 2-3 times a day. In recent years, new drugs have been proposed for the treatment of overactive bladder, such as trospium chloride (spazmex) 10-15 mg 2-3 times a day, tolterodine (detrusitol) 2 mg 2 times a day, and solifenacin (vesicar) 5-10 mg once a day. All anticholinergics have side effects associated with blocking the m-cholinergic receptors of other organs and tissues. Dry mouth, the main side effect of anticholinergics, is caused by blocking the muscarinic receptors of the salivary glands. Other systemic side effects of anticholinergic drugs that block muscarinic cholinergic receptors in various organs include blurred vision, decreased tone of smooth muscle organs (inhibition of intestinal peristalsis, constipation), tachycardia, in some cases central effects (drowsiness, dizziness), etc. It should be noted that trospium chloride is the only quaternary compound in this group and, unlike tertiary amines, it does not penetrate the blood-brain barrier and does not cause side effects from the central nervous system.

Trospium chloride, tolterodine and solifenacin are generally considered to have a better safety profile than oxybutynin. With long-term use of colinoltonics in patients with hyperreactive bladder (especially with nonirogenic detrusor overactivity), impaired contractile activity of the detrusor may develop with the development of chronic urinary retention, ureterohydronephrosis and chronic renal failure. It is especially dangerous to prescribe anticholinergic drugs to patients with hyperreactive bladder in combination with impaired contractile activity of the detrusor. For timely control of possible side effects, it is necessary to monitor residual urine.

Treatment of overactive bladder is also carried out with other drugs - myotropic antispasmodic relaxants, calcium channel blockers (nifedipine, verapamil), tricyclic antidepressants (imipramine). However, the results of treatment with drugs of these groups are in many ways inferior to muscarinic receptor blockers, and therefore they are usually used in combination with the latter.

In severe cases of non-irogenic detrusor overactivity, when anticholinergic drugs are ineffective, intradetrusor injection of botulinum neurotoxin type A and intravesical injection of drugs with neurotoxic activity, such as capsaicin, are used.

The mechanism of action of botulinum neurotoxin type A is presynaptic blockade of acetylcholine release, which leads to relaxation of the detrusor and an increase in bladder volume. 200-300 U of botulinum neurotoxin type A diluted in 10-20 ml of isotonic sodium chloride solution are injected into the detrusor at 20-30 points. In the vast majority of patients, repeated injections of the drug are necessary every 3-12 months to maintain the clinical effect.

Capsaicin causes extreme irritation of unmyelinated C-fibers located in the subepithelial layer of the bladder wall. The neurotoxic effect of capsaicin* is accompanied by a decrease in the increased contractile activity of the detrusor and an increase in the capacity of the bladder. The homovanillic acid derivative capsaicin* is obtained from red hot pepper. The effect of a single intravesical instillation of capsaicin lasts on average 3-4 months, after which repeated administration of the drug is required. Side effects are manifested in the occurrence of a burning sensation and acute reflex contractions of the bladder in the first minutes after administration.

Treatment of overactive bladder also requires the use of neuromodulation, i.e. the process of forming the lost mechanism of urination using direct or indirect stimulation with a weak electric current of the afferent fibers of the somatic part of the peripheral nervous system. The fibers are part of various nerve trunks, but are formed mainly from the third sacral nerve. Impact on them reduces the parasympathetic activity of the pelvic nerve and increases the sympathetic activity of the hypogastric nerve. This leads to inhibition of the increased contractile activity of the detrusor. The most effective are tibial and sacral electrical stimulation.

The technique of electrical stimulation of the tibial nerve consists of irritating it with a weak electric current. For this, a needle electrode is used, which is inserted to a depth of 3-4 cm through the skin to a point located 5 cm cranial from the medial malleolus. The passive electrode is placed in the ankle joint area. One treatment procedure lasts 30 minutes. 12 procedures are carried out, one per week. Patients with the disappearance or improvement of symptoms of overactive bladder are included in the so-called final protocol. This means that in the future, depending on the results of treatment, they are given one procedure for 2-3 weeks. This treatment of overactive bladder does not cause side effects.

The technique of sacral nerve electrical stimulation involves the sequential performance of an acute stimulation test, temporary stimulation, and installation of a permanent electrical stimulator. At the first stage, before implantation of the electrode for temporary stimulation, an acute stimulation test is performed. After infiltration anesthesia with 0.5% procaine (novocaine) solution, an exploratory puncture of the third sacral foramen is performed along the posterior surface of the sacrum. The exploratory needle is connected to the device for external electrical stimulation and an acute stimulation test is performed to determine the position of the needle tip. Irritation of nerve fibers at the S3 level with an electric current leads to contraction of the perineal muscles and plantar flexion of the big toe on the stimulation side, which is regarded as a positive test. After this, an electrode is inserted through the needle into the third sacral foramen. The electrode location is controlled radiologically in the anteroposterior and lateral projections. After implantation, the electrode is fixed to the skin and connected to a portable device for nerve stimulation. The effect is provided by monophasic, rectangular pulses with a width of 210 μs, a frequency of 25 Hz and a voltage of 0.5-5 V. Temporary stimulation is carried out for 3-5 days. The temporary stimulation test is considered positive if the symptoms during the stimulation period are reduced by more than 50% of the initial values and the symptoms recur after the stimulation is stopped. Positive results of the temporary stimulation test serve as an indication for subcutaneous implantation of a permanent stimulator for sacral neuromodulation. Implantation involves the installation of an electrode in the area of the third sacral nerve with a connection to a permanent stimulator placed under the skin in the gluteal region. Complications of sacral neuromodulation: electrode migration and infectious and inflammatory processes.

Surgical treatment of hyperreactive bladder is used extremely rarely and consists of replacing the bladder with a section of intestine (small or large) or myectomy with an increase in the volume of the bladder.

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