What is an overactive bladder?

An overactive bladder is a condition that results from sudden, involuntary contraction of the muscle in the wall of the urinary bladder. Overactive bladder causes a sudden and unstoppable need to urinate (urinary urgency), even though the bladder may only contain a small amount of urine.

Overactive bladder is also referred to as urge incontinence and is a form of urinary incontinence (unintentional loss of urine). Another common type of urinary incontinence is called stress incontinence, which is caused by anatomic weakness in the structures that prevent the bladder from leaking. In general, urinary incontinence is more common in women compared to men.

Although it can happen at any age, overactive bladder is especially common in older adults. Overactive bladder affects an estimated one in 11 adults in the United States. Overactive bladder, however, should not be considered a normal part of aging.

What are the causes of overactive bladder?

Overactive bladder is typically caused by spasms of the muscles of the bladder, resulting in an urge to urinate (hence, urge incontinence). Overactive bladder is primarily a problem of the nerves and muscles of the bladder. Detrusor is one of the major muscles of the bladder. Its contraction in response to filling of the bladder by 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.

Overactive bladder typically results from inappropriate contraction of the detrusor muscle regardless of the amount of urine.

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

• spinal cord injury



• strokes



• Parkinson's disease



• dementia



• multiple sclerosis



• diabetic neuropathy.

There are also some causes of overactive bladder and urge incontinence with a normal nervous system. For example, urinary tract infection, bladder stones, or bladder tumors can cause also cause overactivity of the detrusor muscle, leading to overactive bladder.

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

Are there any risk factors for overactive bladder?

Some of the common risk factors for overactive bladder include

• advanced age (20% of population above 70 years of age may report symptoms of overactive bladder)



• stroke



• spinal cord injury



• dementia



• Parkinson's disease



• diabetes mellitus



• prostate enlargement



• prostate surgery



• multiple pregnancies.

Race is not a risk factor for overactive bladder as it can affect people of all races.

What are symptoms of an overactive bladder?

The symptoms of an overactive bladder include frequent urination, urgency of urination, nocturia (urinating in the middle of the night), and urge incontinence. Overactive bladder may cause significant social, psychological, occupational, domestic, physical, and sexual problems. Again, these symptoms should not be considered a normal part of aging.

How is overactive bladder diagnosed?

Careful medical history and diligent review of symptoms related to overactive bladder are very important. Getting up to urinate at least three times in the middle of the night, increased 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) and a prostate examination in men (to assess for size, tenderness, texture, masses) are helpful in excluding other contributing conditions.

Urine analysis (UA) to assess for infections and occasionally urine cytology (to look for cancer cells in the bladder) are sometimes advised in individuals undergoing evaluation of urinary incontinence and overactive 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, weak bladder muscle).

What are treatments for an overactive bladder?

The treatment for overactive bladder depends on the capabilities of the patient. Generally, treatment can be behavioral retraining, pharmacological (medications), and surgical.

Here are commonly recommended treatments.

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.



• Biofeedback: Used in conjunction with Kegel exercises, biofeedback helps people gain awareness and control of their pelvic 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 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.

What is the role of medications in treating overactive bladder?

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 most common medications (anticholinergics) target to decrease the overactivity of the detrusor muscle. These medications (anticholinergics) should be used under the direction of the physician prescribing them. They may have some common side effects, including dry mouth, constipation, blurry vision, and confusion (in the elderly). Here is a list of the most commonly recommended medications for overactive bladder.

• 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). 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.



• 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.

Tricyclic antidepressants (imipramine [Tofranil] or doxepin [Sinequan, Adapin]) are sometimes used in treating overactive bladder, but their exact mechanism for this application is not clear.

Estrogen, either oral or vaginal, may be helpful in conjunction with other treatments for postmenopausal women with urinary incontinence.

Some of the other newer therapies for overactive bladder are still in trial stages and some are occasionally used in special cases. For example, botulinum toxin injection (Botox) into the detrusor muscle of the bladder may be helpful in some patients with urge incontinence who have responded to other more traditional treatments. There are still other medications for overactive bladder in the research stage that may specifically act on the bladder muscles.

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.

What are treatments for the chronically incontinent?

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: 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: Eliminate dietary caffeine (for those with urge incontinence) and encourage adequate fiber in the diet.



• Disposable absorbent garments: Use these to keep people dry.

What measures can be taken at home to prevent overactive bladder symptoms?

There are simple steps that can reduce symptoms of overactive bladder. For example, 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 fiber in diet 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.

What are some of the complications of overactive bladder?

Common complications that can result from overactive bladder include

• urinary tract infections (UTI),



• skin irritation,



• skin infection,



• bladder stones,



• falls in elderly.

What is the prognosis for overactive bladder?

The overall prognosis for overactive bladder is generally good. The estimated success rate of treatment with the combination of behavioral and medication is about 80%.

Overactive Bladder At A Glance

• Overactive bladder results from sudden, involuntary contraction of the muscle in the wall of the urinary bladder.
• Overactive bladder is a form of urinary incontinence.
• Overactive bladder is not a normal part of aging.
• Treatments available for overactive bladder include pelvic-muscle strengthening, behavioral therapies, and medications.

REFERENCE:

Woodhouse, J.B., P. Patki, K. Patil, J. Shah. "Botulinum Toxin and the Overactive Bladder." Br J Hosp Med 67.9 (2006): 460-464.

Last Editorial Review: 2/9/2010

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