Overactive Bladder

OVERACTIVE BLADDER 

OAB is a symptom complex not a disease.  It should be treated only as a means of improving quality of life.  If treatment does not improve quality of life then no treatment is an acceptable option. Patients may be seeking an evaluation of their symptoms in order to rule out a life-threatening condition.  Once the appropriate evaluation is complete they may not be interested in treatment for mild or moderate OAB symptoms. 

First Line Treatments: 

First line treatments for OAB are behavioral therapies that should be offered to all patients alone or in combination with other modalities as they can be highly effective in improving OAB symptoms have limited or no side effects. Behavioral therapies include; fluid management, bladder training, bladder control strategies, urgency suppression and pelvic floor muscle training and all can be supplemented with biofeedback techniques.

Fluid management includes modification (typically reduction) of fluid intake with respect to volume and/or altering the timing of fluid consumption. Elimination of caffeine and can also result in significant improvement in OAB symptoms. Bladder training is the process of holding off on urination for progressively greater periods of time.  Bladder training alone or in combination with pelvic floor muscle training may help patients control OAB symptoms; however the evidence for efficacy of this approach is limited, with only two randomized controlled trials showing improvement in urgency urinary incontinence. Alternative bladder control strategies include timed voiding, and the use of a voiding diary to determine the mean daytime interval between voids. Patients are instructed to set a new voiding interval shorter than average with the intent to void more frequently to prevent the bladder from reaching the filling state associated with urgency symptoms. As bladder control is improved, the interval may be gradually increased in order to improve bladder carrying capacity.

Biofeedback refers to the use of electronic monitoring of a normally automatic bodily function in order to train a patient to acquire voluntary control of the function. In the context of pelvic floor disorders biofeedback typically refers to placement of external or internal voltage sensors to assess pelvic floor muscular activity; visual or verbal feedback is provided to the patient by a graphic representation and may be useful to guide treatment planning. Biofeedback is often combined with pelvic floor physical therapy, a range of musculoskeletal treatments designed to help manage pelvic floor dysfunction. In treatment of pelvic floor disorders the term pelvic floor muscle training (PFMT) is usually provided by physical therapists. It involves training the pelvic floor muscles to reach their optimum function, and can include massage or stretching of the muscles; this may directly improve pelvic floor muscle tone and pelvic alignment. PFMT can be employed in patient with concurrent pelvic pain of musculoskeletal etiology. Electrical stimulation of the pelvic floor muscles (transvaginal or transanal) has been utilized in pelvic floor muscle dysfunction and has shown benefit for management of OAB.

Second Line Treatments: 

Pharmacological therapies are considered second line but can be used concurrently with behavioral therapies. Oral pharmacotherapies include anti-muscarinics (also called anticholinergics) and the beta-3 agonist mirabegron. Side effects of anti-cholinergics can include dry mouth, constipation, urinary retention and mental status changes. They should not be used in patients with narrow-angle glaucoma or those taking medications with anti-cholinergic properties, such as medications for Parkinson's Disease. Mirabegron needs to be used with caution in patients with high blood pressure. 

Third Line Treatments: 

Third line treatments for OAB include neuromodulation, onabotulinumtoxin (Botox), chronic indwelling catheter, or (rarely)surgical therapy (e.g. augmentation cystoplasty, urinary diversion).

Neuromodulation is based on implantation of permanent electrodes into the sacral nerve roots (sacral nerve stimulation) or placement of temporary percutaneous electrodes in the tibial nerve (percutaneous tibial nerve stimulation). The evidence is strongest for use of neuromodulation in patients with idiopathic (non-neurogenic) OAB refractory to medical management.

Peripheral Tibial Nerve Stimulation (PTNS): The posterior tibial nerve contains fibers from spinal roots L4 through S3 and therefore parallels and cross-talks with sacral fibers of the pelvic floor and bladder. PTNS uses a fine needle alongside the posterior tibial nerve to create feedback. The exact mechanism of action is not known. PTNS has been shown in short term studies to be efficacious for frequency and urgency urinary incontinence. It has been compared to medications with mixed results. There is evidence to suggest that a 12 week course of PTNS may have more lasting effects than the same trial of anticholinergic, however patients must have the ability to return to the office for treatment visits (typically twice weekly) followed by maintenance visits.

Sacral Neuromodulation (SNS): Sacral neuromodulation involves placement of a temporary stimulating lead alongside the S3 nerve root. Feedback alters signaling although the mechanism is incompletely understood. After external testing confirms at least 50% improvement of urgency, frequency, or urge incontinence, a permanent generator may be placed surgically.

The AUA Guideline on overactive bladder summarizes the 13 studies in the literature on efficacy and adverse events of SNS in patients with severe OAB (baseline incontinence episodes 5-11.6 times per day, frequency 13 times per day, and/or > 4 pads per day). Greater than 50% improvement was observed at five years in 68% of patients with urgency incontinence and in 56% of those with frequency-urgency in those who initially had success with the external testing and went on to generator implantation. These numbers are corroborated in other studies. Adverse events include pain at the stimulator or lead site, lead migration, infection, electric shock, and need for surgical revision (greater than 30 % in the majority of studies). Despite this, 90% of patients report being satisfied with the treatment. Due to the presence of the implanted lead and generator, patients need to be informed that special attention will be required at airport security and magnetic resonance imaging carries substantial risk. Patients should be counseled that the device requires periodic replacement and must have the cognitive ability to optimize the device with the remote control.

Botulinum toxin: Botulinum toxin is injected cystoscopically at multiple sites into the submucosa or the bladder. The evidence for efficacy of botulinum toxin in idiopathic (non-neurogenic) OAB has emerged in support of its use and is summarized by Santos-Silva et al, usually as third line therapy, and is best studied for onabotulinum toxin A (onabotA). Two large regulatory phase 3 randomized controlled trials have now been concluded by Nitti and Chapple which showed three to four-fold greater reductions from baseline in the mean daily frequency of urinary incontinence episodes with onabotA 100 U versus placebo and a significant improvement of the number of incontinence episodes in a 3-day bladder diary. The UTI rate after onabotA was 15.5 to 20.4% and rate of initiating self catheterization was 6.1 to 6.9% versus 0 to 0.7% in the onabotA versus placebo arms respectively. Patients receiving onabotA must be willing to return to the office for a follow up PVR and must be counseled on the risk of needing clean intermittent catheterization for a period of time after the procedure. One study comparing antimuscarinics to 100u onabotA showed similar mean reduction in episodes of incontinence but side effect profiles differed. There is room for investigation into other protein complexes, the effect of various onabotA dilution concentrations during reconstitution, as well as trigone sparing versus trigone inclusive injections, with one study showing benefit of trigone inclusion for refractory symptoms without inducing de novo reflux. In motivated patients with complex OAB and concurrent incomplete emptying, either preexisting or due to onabotA, the addition of clean intermittent catheterization in combination with onabotA can lead to significant symptom control. Risks of botulinum toxin include urinary retention and UTI.

Indwelling Catheters: Indwelling catheters are viewed as an undesirable alternative for the management of OAB. When the emptying pattern is safe, spontaneous void into absorbent garments is considered superior due to the incidence of upper tract damage, vesicoureteral reflux, urolithiasis, urinary tract infection, and possibly malignant transformation of the urothelium with indwelling catheters. Suprapubic catheter has a lower incidence of urethral stricture and injury than urethral catheters.

Augmentation Cystoplasty and Diversion: Although it is tempting to employ augmentation cystoplasty in the treatment of idiopathic OAB, the results are not as good as for neurogenic detrusor overactivity. Long-term symptomatic success was reported in as few as 53-58% of idiopathic patients, versus 92% in neuropathic patients. Ileal conduit urinary diversion would be reserved for only the most extreme of situations, with a complication rate of 36% over time, and consideration must be given to concurrent cystectomy. Bladder replacement with a continent reservoir is another extremely rare choice.

Most providers treating overactive bladder offer a combination of the treatment options above. There is some evidence that combination therapy is more effective than monotherapy.