With an overactive bladder, you may:

• Feel a sudden urge to urinate that's difficult to control
• Experience urge incontinence — the involuntary loss of urine immediately following an urgent need to urinate
• Urinate frequently, usually eight or more times in 24 hours
• Awaken two or more times in the night to urinate (nocturia)

Although you may be able to get to the toilet in time when you sense an urge to urinate, unexpected frequent urination and nighttime urination can disrupt your life.

Normal bladder function

The kidneys produce urine, which drains into your bladder. When you urinate, urine passes from your bladder through an opening at the bottom and flows out a tube called the urethra (u-REE-thruh).

In women, the urethral opening is located just above the vagina. In men, the urethral opening is at the tip of the penis.

As your bladder fills, nerve signals sent to your brain eventually trigger the need to urinate. When you urinate, nerve signals coordinate the relaxation of the pelvic floor muscles and the muscles of the urethra (urinary sphincter muscles). The muscles of the bladder tighten (contract), pushing the urine out.

Involuntary bladder contractions

Overactive bladder occurs because the muscles of the bladder start to contract involuntarily even when the volume of urine in your bladder is low. This involuntary contraction creates the urgent need to urinate.

Several conditions may contribute to signs and symptoms of overactive bladder, including:

• Neurological disorders, such as stroke and multiple sclerosis
• Diabetes
• Medications that cause a rapid increase in urine production or require that you take them with lots of fluids
• Acute urinary tract infections that can cause symptoms similar to an overactive bladder
• Abnormalities in the bladder, such as tumors or bladder stones
• Factors that obstruct bladder outflow — enlarged prostate, constipation or previous operations to treat other forms of incontinence
• Excess consumption of caffeine or alcohol
• Declining cognitive function due to aging, which may make it more difficult for your bladder to understand the signals it receives from your brain
• Difficulty walking, which can lead to bladder urgency if you're unable to get to the bathroom quickly
• Incomplete bladder emptying, which may lead to symptoms of overactive bladder, as you have little urine storage space left

The specific cause of an overactive bladder may be unknown.

As you age, you're at increased risk of developing overactive bladder. You're also at higher risk of diseases and disorders, such as enlarged prostate and diabetes, which can contribute to other problems with bladder function.

Many people with cognitive decline — for instance, after a stroke or with Alzheimer's disease — develop an overactive bladder. Incontinence that results from situations like this can be managed with fluid schedules, timed and prompted voiding, absorbent garments, and bowel programs.

Some people with an overactive bladder also have bowel control problems; tell your doctor if this is a problem for you.

Any type of incontinence can affect your overall quality of life. If your overactive bladder symptoms cause a major disruption to your life, you might also have:

• Emotional distress or depression
• Anxiety
• Sleep disturbances and interrupted sleep cycles
• Issues with sexuality

Your doctor might recommend treatment of associated conditions, to see if effective treatment of an associated condition will help with your urinary symptoms.

Some women also may have a disorder called mixed incontinence, when both urge and stress incontinence occur. Stress incontinence is the loss of urine when you exert physical stress or pressure on your bladder, such as during activities that include running or jumping. Treatment of the stress incontinence is not likely to help the overactive bladder symptoms.

Older people may have a common combination of bladder storage problems and bladder-emptying issues. The bladder may cause a lot of urgency and even incontinence, but it doesn't empty well. A specialist may be able to help you with this combination of bladder problems.