The bladder is a hollow organ in the abdomen that holds urine. When the bladder is full, it contracts, and urine is expelled from the body through the urethra. Overactive bladder starts with a muscle contraction in the bladder wall. The result is a need to urinate (urinary urgency), which is also called urge incontinence or irritable bladder.
While overactive bladder is most common in older adults, the condition is not a normal result of aging. While one in 11 people in the United States suffer from overactive bladder, it mainly affects people 65 and older, although women can be affected earlier, often in their mid-forties.
Causes and Risk Factors for Overactive Bladder
Overactive bladder is caused by a malfunction of the detrusor muscle, which in turn can be cased by:
- Nerve damage caused by abdominal trauma, pelvic trauma or surgery
- Bladder stones
- Drug side effects
- Neurological diseases, such as multiple sclerosis, Parkinson's disease, stroke or spinal cord lesions
- Bladder cancer
- Prostate cancer
- Urinary tract infection
- Normal pressure hydrocephalus
Symptoms of Overactive Bladder
Symptoms of overactive bladder include:
- Frequent urination
- Urgency (need to urinate)
- Leaking or involuntary, and/or complete bladder voiding (urge incontinence)
- Need to urinate frequently (eight or more times in 24 hours)
- Nocturia or waking up two or more times at night to urinate
There are two kinds of overactive bladder. One without urge incontinence, which is called overactive bladder, dry, and affects two thirds of sufferers; and overactive bladder, wet, which includes the symptoms with urge incontinence (leaking or involuntary bladder voiding).
Diagnosing Overactive Bladder
A preliminary assessment for suspected overactive bladder can include a screening questionnaire, a request that the patient maintain a voiding diary for a prescribed number of days, a detailed medical history, and a comprehensive physical examination. Often a urinalysis, which detects the presence of bacteria in urine and indicates infection, will be ordered to determine if the condition is caused by an infection. A urinalysis also can determine if there is blood or too much protein in the urine, which may indicate kidney or cardiac disease, and can also detect the presence of puss in urine, which is also a sign of infection.
The physical examination for overactive bladder includes checking the neurological status of a patient for any sensory issues, as well as a cough stress test to measure urine loss, whether as an immediate or a delayed reaction. The exam will usually include a check of the abdomen, rectum, genitals and pelvis.
Specialized Tests for Overactive Bladder
Specialized diagnostics for overactive bladder are called urodynamic tests. They assess bladder function, measure the amount of urine after voiding, the degree of incontinence (how completely the bladder empties), and bladder irritability. Measurements are performed by inserting a thin tube through the urethra into the bladder or by performing an ultrasound to acquire an image of the bladder.
Other specialized tests include:
- Uroflowmetry is a diagnostic test that uses a device that measures the volume and speed of urination.
- Cystometry uses a device called a cystometer to measure the pressure of the bladder and its capacity. It also evaluates the function of the detrusor muscle to determine the degree of muscle contraction, the pressure of any leakage, and the pressure required to fully empty the bladder.
- Electromyography is used to assess the coordination of nerve impulses in the bladder muscles and in the urinary sphincter. Sensors are placed on the abdominal region or catheters are inserted into the urethra or rectum to measure the nerve impulses.
- Video Urodynamics uses imaging and ultrasound to create images of the bladder, both filled and after voiding.
- Cystoscopy is a test in which a thin tube with a camera at one end is used to see the interior of the urethra and the bladder.
Treating Overactive Bladder
In addition to medication, behavioral interventions for an overactive bladder may help reduce episodes and strengthen bladder muscles. Bladder training, which includes the delay of voiding from 10 minutes to two hours, can be done to strengthen bladder muscles. Pelvic floor muscle exercises, also called Kegel exercises, can improve function of the pelvic floor muscles and urinary sphincter to hold urine and suppress involuntary movement of the bladder. Vaginal weight training is a process by which small weights are held within the vagina through the tightening of the vaginal muscles. These exercises are recommended twice daily for approximately 15 minutes for four to six weeks. Biofeedback in combination with Kegel exercises can also help the patient build build awareness and control of pelvic muscles.
Other possible treatments include adjusting fluid intakes and reducing irritants, such as limiting caffeine and alcohol. Patients can also try increasing fiber intake or taking supplements for constipation, which can reduce the symptoms of overactive bladder.
In some cases, absorbent pads can be worn to protect undergarments and prevent embarrassment.
Medication for Overactive Bladder
The use of antisasmodics, also called anticholinergics can reduce bladder urge episodes. These include:
- Tolterodine (Detrol)
- Oxybutynin (Ditropan)
- Oxybutynin skin patch (Oxytrol)
- Trospium (Sanctura)
- Solifenacin (Vesicare)
Surgery for Overactive Bladder
For severe cases of overactive bladder, a sacral nerve stimulator may be recommended. This is a pacemaker-type device placed under the skin of the abdomin and connected to a wire near the sacral nerves (near the tailbone). The sacral nerves are the primary link between the spinal cord and bladder tissue. Modulating these nerve impulses has been shown to be an effective treatment for overactive bladder.
In some cases, augmentation cystoplasty may be recommended. This is a reconstructive procedure that uses parts of the bowel to replace parts of the bladder. It can improve bladder capacity, although the use of a catheter for voiding may still be necessary.