Overactive Bladder

(OAB)

The Facts

A person who has been diagnosed with the medical condition known as overactive bladder, or OAB, has sudden urges to empty their bladder. In fact, most people with OAB visit the bathroom eight or more times a day. This medical condition is very common, affecting approximately 1 in 5 Canadians over the age of 35 years. When OAB is accompanied by an involuntary loss of moderate-to-large amounts of urine, the condition is called urge incontinence.

OAB is caused by sudden involuntary contractions of the detrusor muscle, which is in the wall of the bladder. Although OAB can occur at any age, it is more likely to occur as a person ages. However, it shouldn't be passed off as a normal part of growing older.

The Causes

**Overactive bladder (OAB) is caused by a hyperactive bladder wall, meaning the bladder wall contracts involuntarily and excessively. **It can also be caused by disorders of the central nervous system. Pregnancy may contribute to OAB because childbirth can make pelvic muscles stretch and weaken. This change can cause the bladder to sag out of its normal position, leading to leakage. Many medical conditions can also increase the risk for OAB. These include dementia, diabetes, multiple sclerosis, Parkinson's disease, spinal cord injury, urinary tract infection, and stroke. The risk for OAB can also be increased by excess intake of caffeine, alcohol, or fluid in general. Constipation and certain medications can also increase your risk for OAB. Medications which increase the risk for OAB include diuretics (water pills) and certain medications used to treat psychiatric conditions such as depression.

Symptoms And Complications

Although all people with OAB have sudden intense urges to empty their bladder and usually visit the bathroom at least eight times a day (urinary frequency), other symptoms of OAB may vary between people. Some people may have accidental loss of urine (urge incontinence), while others may need to get up many times during the night to urinate (nocturia). Emotional problems can occur when a person with OAB doesn't seek help and lets their condition affect their work and social life. OAB may affect your self-esteem, professional life, sleep, social activities, and sexual relations. If you think you might have OAB, it is very important to see your doctor as studies have shown that treatment may greatly improve your quality of life.

Making A Diagnosis

To make a diagnosis of OAB, the doctor needs to first take a full medical history and rule out other possible causes of your symptoms. Other conditions, such as urinary tract infections or UTIs, certain inflammations of the vagina, multiple sclerosis, bladder stones, and diabetes, may cause symptoms similar to OAB. The doctor needs to rule these out by ordering laboratory tests (e.g., urinalysis) to check for such things as increased blood sugar levels or signs of infection in the urine.

Your doctor may also do renal function tests to look at how well your kidneys are functioning. In some instances, your doctor or a specialist can do urodynamic testing where they can measure how well your detrusor muscle (the smooth muscle lining in the bladder) is working, check for post-void residual volume (i.e., how much urine is left in your bladder after you’ve urinated) and your bladder capacity (i.e., how much urine your bladder can hold at a given time).

If the doctor suspects you have OAB, you may be asked to keep a diary over at least a three-day period to determine how many times a day you empty your bladder. Your doctor will diagnose you with OAB when all other possible causes of your symptoms are ruled out and OAB is the most likely explanation.

Treatment And Prevention

Prevention

Prevention of OAB is based on making certain changes in your lifestyle. Eating a healthy high-fibre diet, which reduces risk for constipation, and limiting intake of caffeine and alcohol will reduce the risk of OAB. Limiting your fluid intake before bed will reduce your need to void during the night. If you find that certain medications (e.g., diuretics or water pills) have increased your urge to empty your bladder, you should discuss this with your doctor. Do not stop taking any medications without talking to your doctor.

Treatment

There are many effective treatments for OAB.

Non-medication treatment options include:

Kegel or pelvic floor retraining exercises – These exercises teach you how to strengthen the muscles of the pelvic floor. By contracting the muscles that support the bladder, you strengthen and tighten the bladder outlet. These exercises need to be done on a regular basis and as discussed with your health professional in order for them to be successful.

Bladder training or bladder drill – By gradually increasing the time between each visit to the bathroom you may be able to train your bladder so that the urge to urinate does not occur as often. Your doctor will provide education on this technique and how to schedule your bathroom visits. While you are doing this, your doctor may ask you to reduce your fluid intake. Always discuss any change of fluid intake with your doctor.

Absorbent products – Products such as pads or undergarments designed for bladder disorders may be worn to reduce odour and skin irritation.

Surgery – Those who don't experience relief from OAB with medications or other treatments may benefit from surgery. Surgery may be aimed at reducing the nerve stimulation that causes the involuntary contractions of the bladder, increasing the size of the bladder, or creating a different pathway for urine to be drained.

Medications for OAB include:*

Antimuscarinic (antispasmodic) medications – These medications reduce the number of involuntary bladder contractions by preventing spasm of the detrusor muscle that causes them, and increase bladder capacity. In general, these medications can reduce leakage of urine caused by OAB by 60% to 75%. Examples of antimuscarinic medications include:

darifenacin
fesoterodine
oxybutynin
solifenacin
tolterodine
trospium

The most common side effects of antimuscarinic medications are dry mouth, dry eyes, increased pressure inside the eye, and constipation. Be sure to tell your doctor about all of the medications you are taking and all of your medical conditions, as there are some people who should not take antimuscarinic medications. These side effects can be minimized by starting with a low dose of medication and gradually increasing the dose.

Beta3-agonist – This is another type of medication for the treatment of OAB. It helps relax the detrusor muscle (in the bladder wall) to prevent unwanted spasms that may cause symptoms of OAB. Currently there is only one drug in this category called "mirabegron". An uncommon side effect of mirabegron is an increase in blood pressure. Be sure to tell your doctor about all of the medications you are taking and all of your medical conditions, as there are some people who should not take this medication.

For those who cannot tolerate anti-muscarinic medications, botulinum toxin injection may help to decrease urge incontinence.

In some instances of post-menopausal urge incontinence, where the person is also experiencing vaginal dryness or discomfort, oral or vaginal estrogen has been used. However, there is currently no evidence to suggest using estrogen solely for urge incontinence. Talk to your doctor about your individual health needs, other medical conditions, and risk factors for using estrogen (i.e., a history of breast cancer, previous heart attack, or blood clots).