Overactive Bladder (OAB)

Urinary urgency and frequent urination are symptoms of overactive bladder.

• Overactive bladder is a syndrome (set of symptoms) that is thought to be due to sudden contractions of the muscle in the wall of the bladder.
• Overactive bladder can also result in urinary incontinence, otherwise termed urgency urinary incontinence (wet OAB).
• Overactive bladder is not a normal part of aging, but the risk of developing OAB increases with age.
• OAB affects both men and women and can significantly impact the quality of life.
• Many treatments are available for overactive bladder, including pelvic-muscle strengthening, behavioral therapies, medications, neuromodulation, and surgery.

Overactive bladder (OAB) is a condition that is characterized by sudden, involuntary contraction of the muscle in the wall of the urinary bladder. This results in a sudden, compelling need to urinate that is difficult to suppress (urinary urgency), even though the bladder may only contain a small amount of urine. The key symptom is sudden urge to void (urgency) with or without urgency urinary incontinence, often associated with urinary frequency (voiding 8 or more times per day) and nocturia (awakening one or more times at night to void). Irritating fluids, such as caffeinated beverages (coffee, tea), spicy foods, and alcohol can worsen the symptoms. It is common for those affected to compensate for OAB by toilet mapping, fluid restriction, and timed voiding. There is no pain, burning, or blood in the urine with OAB.

Overactive bladder coupled with urinary leakage (inability to suppress the urge to void) is also referred to as urgency urinary incontinence. Another common type of urinary incontinence is called stress incontinence, which is caused by weakness in the pelvic floor muscles that surround and support the bladder and urethra. The symptom of stress incontinence is leakage when coughing, straining, jumping, or with other physical activity that increase the pressure in the abdomen (Valsalva). Treatment for stress incontinence is very different than urge incontinence. In some individuals, there can be a combination of urge and stress incontinence (mixed incontinence). Often, the most bothersome condition is treated first in individuals with mixed urinary incontinence. In general, urinary incontinence is more common in women compared to men.

The overall prevalence of overactive bladder is 13.9%, affecting men and women with equal frequency. Although it can happen at any age, overactive bladder is especially common in older adults. Overactive bladder should not be considered a normal part of aging. The prevalence under the age of 50 is < 10%. After age 60, the prevalence increases to 20%-30%. It is estimated that 60% of patients have dry OAB (no leakage) while 40% have wet OAB.

Overactive bladder is typically caused by early, uncontrolled contraction (spasms) of the bladder muscle (detrusor muscle), resulting in an urge to urinate. Overactive bladder is primarily a problem of the nerves and muscles of the bladder that allow for early contraction during the normal relaxation phase of bladder filling. The bladder's contraction in response to filling with urine is one the steps in the normal process of urination. The contraction and relaxation of the detrusor muscle is regulated by the nervous system. Approximately 300 cc of urine in the bladder can signal the nervous to trigger muscles of the bladder to coordinate urination. Voluntary control of the sphincter muscles at the opening of the bladder can hold the urine in the bladder for longer. Up to 600 cc of urine can be contained in a normal adult bladder. For those with OAB, the bladder capacity is typically low (< 200cc).

Overactive bladder typically results from inappropriate contraction of the detrusor muscle regardless of the amount of urine. The most common form of OAB is idiopathic, where the exact cause is not known. However, OAB can result from problems of the nervous system.

The common abnormalities of the nervous system that cause overactive bladder are

• spinal cord injury,
• back problems (disc hernia, degenerative disc disease),
• strokes,
• Parkinson's disease,
• dementia,
• multiple sclerosis, and
• diabetic neuropathy.

Other causes of OAB symptoms include urinary tract infection, bladder stones, urethral strictures, benign prostatic enlargement (BPH), or bladder tumors.

Frequently, no apparent cause of overactive bladder can be determined (idiopathic overactive bladder).

Some of the common risk factors for overactive bladder include the following:

• Advanced age
• Injury to the nervous system
  • Stroke
  • Spinal cord injury
  • Dementia
  • Parkinson's disease
  • Multiple sclerosis
• Diabetes mellitus
• Prostate enlargement
• Prostate surgery
• Multiple pregnancies
• Previous pelvic surgery
• Previous radiotherapy of the pelvis
• Postmenopausal women have an increased risk of OAB.
• Race may affect risk of developing OAB: African-American and Hispanic men and women have a higher risk of developing OAB.
• Obesity also appears to increase the risk of OAB.
• OAB is also associated with depression, anxiety, and other symptoms.

The symptoms of an overactive bladder include frequent urination (urinating eight or more times per day), urgency of urination (sudden, compelling desire to void that is difficult to defer) with or without urgency urinary incontinence, and nocturia (awakening one or more times at night to urinate). Overactive bladder may cause significant social, psychological, occupational, domestic, physical, sexual, and financial problems. Again, these symptoms should not be considered a normal part of aging.

The diagnosis of overactive bladder is based on the presence of symptoms, while excluding other conditions that may cause similar symptoms. This is based on history, physical examination, and a urine test. Waking up to urinate one or more times at night, urinary frequency (urinating at least eight times daily), urinary urgency, and urinary incontinence are all important clues in evaluating someone suspected of having overactive bladder.

In addition to a general physical examination, a pelvic exam in women (to assess for dryness, atrophy, inflammation, infection, stress incontinence, pelvic organ prolapse [seeing a bulge in the vagina particularly with increasing abdominal pressure by straining]) and a prostate examination in men (to assess for size, tenderness, texture, and/or masses) are helpful in excluding other contributing conditions.

Urine analysis (UA) to assess for infection, blood cells in the urine, and high levels of glucose (sugar) in the urine is recommended. Occasionally, urine cytology (to look for cancer cells in the bladder) is sometimes advised in individuals undergoing evaluation of urinary incontinence and overactive bladder, particularly individuals with blood cells in the urine (hematuria). Bladder ultrasound measurement of the amount of urine left in the bladder after urination (called post-void residual) may also provide additional information about the cause of urinary incontinence (obstruction to urine flow or weak bladder muscle) but is not needed in all individuals with OAB symptoms.

The treatment for overactive bladder can vary with each individual. Guidelines suggest starting with less invasive therapies first. The recommended first line of therapy is behavioral, dietary, and lifestyle therapies. In some individuals, the addition of biofeedback is helpful. Biofeedback may be done in the office or by a physical therapist. In those individuals who do not respond adequately to behavioral, dietary, or lifestyle therapies, the addition of medications (pharmacologic therapy) is recommended as a second-line treatment. Third-line therapies consist of less-invasive surgical options (injection of botulinum toxin into the bladder wall) and electrical stimulation therapies, including sacral neuromodulation (Interstim) and peripheral nerve stimulation (PTNS). More extensive surgical therapies are available but are rarely needed for treatment of OAB that is not the result of a nervous system condition.

Here are commonly recommended treatments.

First-Line Treatments

Dietary and Lifestyle

• Weight loss in obese individuals may decrease incontinence episodes.
• Reducing fluid intake to a recommended daily amount may be helpful in decreasing OAB symptoms.
• Decreasing/eliminating caffeine intake may be helpful in some individuals.

Behavioral

Pelvic muscle rehabilitation to improve pelvic muscle tone and prevent leakage

• Kegel exercises: Regular, daily exercising of pelvic muscles can improve, and even prevent, urinary incontinence. This is particularly helpful for younger women. These exercises should be performed 30-80 times daily for at least eight weeks. These exercises are thought to strengthen the muscles of the pelvis and urethra, which can support the opening to the bladder to prevent incontinence. Their success depends on practicing the proper technique and the recommended frequency. These exercises may be helpful for women with both stress and urgency urinary incontinence.
• Biofeedback: Used in conjunction with Kegel exercises, biofeedback helps people gain awareness and control of their pelvic muscles. Biofeedback is often performed by a physical therapist but may also be performed in the office of a urologist or urogynecologist. Biofeedback can help identify the pelvic floor muscles to ensure proper contractions of these muscles.
• Vaginal weight training: Small weights are held within the vagina by tightening the vaginal muscles. These exercises should be performed for 15 minutes, twice daily, for four to six weeks.
• Pelvic-floor electrical stimulation: Mild electrical pulses stimulate muscle contractions. This should be done in conjunction with Kegel exercises.

Behavioral therapies to help people regain control of their bladder

• Bladder training teaches people to resist the urge to void by conscious suppression of the need to urinate as well as using pelvic floor muscle contractions to suppress the urge to void and gradually expand the intervals between voiding.
• Toileting assistance uses routine or scheduled toileting, habit-training schedules, and prompted voiding to empty the bladder regularly to prevent leaking.

There are several medications recommended for the treatment of overactive bladder. Using these medications in conjunction with behavioral therapies has shown to increase the success rate for the treatment of overactive bladder.

The main goals of OAB treatment are to

1. reduce urinary urgency and frequency,
2. increase voided volume (bladder capacity), and
3. decrease urge incontinence (reduce leakage episodes).

Typically, the medications for overactive bladder start to work within one to two weeks, and optimal relief of OAB symptoms is usually achieved by six weeks. The most common medications (anticholinergics), bladder relaxants, target to decrease the overactivity of the detrusor muscle. Anticholinergics should be used under the direction of the physician prescribing them. They may have some common side effects, including dry mouth, constipation, facial flushing, blurry vision, and confusion (in the elderly). There are multiple anticholinergic therapies approved for the treatment of overactive bladder. They all are similar in their ability to treat the symptoms of overactive bladder but differ in the frequency and type of side effects as well as method of use. Some are once daily, some are topical treatments applied to the skin, and some come in different doses, allowing one to increase the dose if needed. Lastly, several of these medications are now available in generic forms.

Anticholinergic class

• Oxybutynin (Ditropan) prevents urge incontinence by relaxing the detrusor muscle. This is typically taken two to three times a day (Ditropan XL is extended release, taken once a day). This medication was the first-generation therapy available, and its main side effects include dry mouth (60%) and constipation. Ditropan patch (Oxytrol) is also available with fewer side effects, but it releases a smaller dose than the oral form. The patch is placed on the skin once to twice weekly, and it may cause some local skin irritation.
• Tolterodine (Detrol, Detrol LA) is indicated for the treatment of an overactive bladder with symptoms of urinary frequency, urgency, or urge incontinence. This medication affects the salivary glands less than oxybutynin, thus, it is better tolerated with fewer side effects (dry mouth). Detrol is usually prescribed twice a day, whereas the long-acting type (Detrol LA) is taken only once a day.
• Trospium chloride (Sanctura) is available in both a once a day and twice a day therapy. Trospium is less likely to get into the brain and is broken down differently than other medications, which may be beneficial in some individuals.
• Solifenacin (Vesicare) is a relatively newer medication in this group. It is generally similar to tolterodine, but it has a longer half-life and needs to be taken once a day.
• Darifenacin (Enablex) is also a newer anticholinergic medicine for treating overactive bladder with fewer side effects, such as confusion. Therefore, it may be more helpful in the elderly with underlying dementia. This medication is also typically taken once a day.
• Fesoterodine fumarate (Toviaz) is indicated for the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and frequency. The medication is taken once daily. Common side effects include constipation and dry mouth.

Contraindications: The use of anticholinergics in individuals with narrow-angle glaucoma is not recommended without approval from an eye specialist. The side effects of anticholinergic medications for OAB may be increased with the use of other medications, thus it is important to always review current medications with the prescribing physician prior to starting an anticholinergic.

B3-Agonist class

• Mirabegron (Myrbetriq) is a new type of medication, a beta 3-adrenoceptor agonist, to treat overactive bladder that is not an anticholinergic and can be used alone or more recently is being tested in combination with anticholinergic medications. Unlike anticholinergic medications that work to prevent the bladder muscle from contracting, the beta-3 adrenoceptor agonists work on the bladder to help it to relax. As these medications have a very different mechanism of action, they have different side effects. The side effects include increased blood pressure, incomplete bladder emptying, sinus irritation, constipation, and dry mouth (< 2%-3%). Currently, mirabegron is the only drug of this type that is FDA approved, however, other similar agents are being studied.
  • It is recommended that blood pressure checks be performed when starting mirabegron.

Botox injection class

Injection of botulinum toxin into the bladder is considered a third-line therapy for the treatment of overactive bladder and is used in individuals who have tried and failed and/or cannot tolerate the side effects of medical therapy and/or has contraindications to the use of medications to treat overactive bladder.

• OnabotulinumtoxinA (Botox) is a toxin that is injected directly into the bladder muscle with a cystoscope and may be repeated every four to six months. The effects of the toxin are to prevent the release of chemicals from the nerves that supply the bladder, preventing stimulation of the bladder muscle. As the chemical cannot spread very far when injected, to treat the bladder adequately, multiple injections of a small amount of the toxin are necessary for the treatment to be effective. In most individuals, this can be done in the office. The treatment does not cause permanent changes and thus will require periodic retreatments for the effect to be continued. Serious side effects are unusual but may include difficulty breathing, difficulty swallowing, difficulty talking, muscle weakness, and more commonly, urinary tract infection and urinary retention. Individuals undergoing injection of Botox into the bladder muscle must be willing to perform clean, intermittent catheterization to empty the bladder.
• The effect of Botox is not permanent, thus repeat injections are needed to maintain the improvement, typically once every six to 16 months.
• Estrogen, either oral or vaginal, may be helpful in conjunction with other treatments for postmenopausal women with urinary incontinence.

Another third-line therapy is neuromodulation.

Neuromodulation is a newer method of treating overactive bladder with electrical stimulation that results in reorganization of the spinal reflexes involved in bladder control. There are two types of neuromodulation available: percutaneous tibial nerve stimulation (PTNS) and sacral neuromodulation (Interstim). PTNS is performed in the office and is usually performed once a week for 12 weeks with periodic therapies thereafter to maintain a response. It involves placing a small needle into the area near the ankle and administering electrical stimulation. Sacral neuromodulation is usually performed in two stages. The first stage involves the placement of wires (leads) into areas in the sacrum and then using a small generator to test the response to stimulation. If there is a 50% or more improvement in symptoms the wires (leads) are internalized and an internal generator is placed, typically under the skin near the buttocks.

Surgery is rarely necessary in treating overactive bladder unless symptoms are debilitating and unresponsive to other treatments. Reconstructive bladder surgery (cystoplasty) is the most common surgical procedure. This surgery involves enlarging the size of the bladder by using part of the intestine.

There is limited information on the effects of acupuncture on OAB symptoms. However, small studies have demonstrated improvements in OAB symptoms.

Select herbal therapies have also demonstrated improvement in OAB symptoms in small studies.

Although many people will improve their continence through medications, pelvic-muscle exercises, and bladder training, some will never achieve complete dryness. Sometimes treatment failures are due to concurrent use of other necessary medications, such as diuretics (water pills that increase urination), that actually can cause incontinence. Others may have dementia or other physical impairments that keep them from being able to perform pelvic-muscle exercises or retrain their bladders. Many will be cared for in long-term care facilities or at home. The following recommendations can help keep the chronically incontinent drier and reduce their cost of care:

• Scheduled toileting (timed voiding): Take people to the toilet every two to four hours or according to their toilet habits.
• Prompted voiding: Check for dryness and encourage use of the toilet.
• Improved access to toilets: Use equipment such as canes, walkers, wheelchairs, and devices that raise the seating level of toilets to make toileting easier.
• Managing fluids and diet: Behavioral modifications can directly impact symptoms of OAB. These include eliminating dietary caffeine, alcohol, and spicy foods (for those with urge incontinence) and encourage adequate fiber in the diet.
• Disposable absorbent garments: Use these to keep people dry.
• Avoid indwelling catheters as much as possible, as these are associated with a risk of urinary tract infection, stones, and urethral and bladder irritation.

The exact cause of overactive bladder syndrome is not known, thus preventative strategies are not established. However, the following options can avoid exacerbating symptoms in some individuals.

Caffeine may exacerbate urinary urgency, and it is potentially an irritant to the bladder. Eliminating caffeine intake can diminish some of the symptoms of overactive bladder.

Some experts suggest that avoidance of certain foods, such as chocolate, spicy foods, alcohol, carbonated beverages, and nuts, can be beneficial in preventing symptoms of overactive bladder. Others encourage increasing the amount of dietary fiber for people with overactive bladder. Limiting fluid intake can also help to reduce urinary frequency.

Excess weight can put more pressure on the bladder, causing urinary incontinence. Therefore, weight loss can also help with urinary incontinence in general.

Common complications that can result from overactive bladder include

• urinary tract infections (UTIs),
• skin irritation,
• skin infection,
• bladder stones,
• falls/fractures in elderly,
• sleep disturbances,
• negative impact on quality of life, and
• depression.

The overall prognosis for overactive bladder is generally good. Through a combined approach of behavioral modifications and medications, the patient can help significantly improve bladder urgency, and the quality of life of those affected by overactive bladder can substantially improve.