Overactive Bladder

Overactive bladder causes an abrupt and hard-to-control need to urinate.

What Is Overactive Bladder?

An overactive bladder is caused by a sudden, involuntary contraction of the muscle in the wall of the urinary bladder. Overactive bladder causes an abrupt and hard-to-control need to urinate, referred to as urinary urgency. Overactive bladder is also known as urge incontinence * and is a form of urinary incontinence (unintentional loss of urine). Overactive bladder is most common in older adults. It affects approximately 1 in 11 adults in the United States.

What Causes Overactive Bladder?

The bladder functions by filling with urine and then emptying. This process requires a complex interaction between the kidneys, nerve impulses, and muscular activity. When defective, various parts of this process can contribute to overactive bladder and urge incontinence.

Normal bladder function

The kidneys are responsible for filtering waste from the blood and producing urine. The urine then travels down a pair of tubes called the ureters from the kidneys to the bladder. The bladder fills with urine but holds the urine until it is time to void (release) it by going to the bathroom. During voiding, urine drains from the bladder through an opening (called the neck) and flows out of the body through a short tube called the urethra. In women, the urethral opening is located just above the opening to the vagina, whereas in men, it is at the tip of the penis.

Anatomy of the kidneys and urinary tract.

Anatomy of the kidneys and urinary tract.
Illustration by Frank Forney. © 2016 Cengage Learning®.
Abnormal bladder function

Often, overactive bladder symptoms occur because the muscles of the bladder involuntarily contract. The contraction of the bladder muscles creates urinary urgency. If the urinary sphincter remains constricted, it will prevent the bladder from leaking. However, if the urinary sphincter is overwhelmed by the bladder muscle contraction, involuntary urination occurs.

What Are the Symptoms of Overactive Bladder?

Symptoms associated with overactive bladder include frequent urination, usually at least eight times per day. Awakening to urinate at night usually occurs at least twice. There is a sense of urinary urgency, and an involuntary loss of urine immediately following the urgent need to urinate (urge incontinence). Some individuals may also have what is called mixed incontinence, when both urge incontinence and stress incontinence occur. Stress incontinence is an involuntary loss of urine in response to the pressure caused by physical stressors such as coughing or laughing, which increase the pressure within the abdomen and pelvis.

What Are the Risk Factors for Developing an Overactive Bladder?

Overactive bladder is not considered a normal part of aging. However, the risk of experiencing overactive bladder increases with age. Older adults are also more likely to get diseases that cause problems with bladder function, such as enlarged prostate and diabetes. Neurological disorders such as Parkinson's disease * , stroke * , and multiple sclerosis * have been associated with overactive bladder. Lifestyle decisions that may reduce risk of overactive bladder include getting regular exercise, eating a high-fiber diet, and limiting caffeine and alcohol. Individuals who have an overactive bladder and whose lives are severely disrupted are at increased risk for depression.

How Is Overactive Bladder Diagnosed?

In the initial stages of an overactive bladder diagnosis, other medical issues that may be causing symptoms need to be ruled out. Medical history and a physical exam focusing on the abdomen and genitals are necessary. A urine test may be performed in order to rule out urinary tract infection. Once other more common causes of urinary urgency have been ruled out, three specialized tests may be performed.

Urodynamic tests assess bladder function, including the ability to empty completely. This aspect of bladder function is assessed by measuring the urine left in the bladder after voiding is complete. Failure of the bladder to empty completely may cause symptoms similar to overactive bladder.

Cystometry is performed to measure the pressure inside the bladder and assess bladder function. In this test, two catheters * are used. The first enters the bladder and fills the bladder with water. The second catheter is attached to a pressure-measuring sensor and placed near the bladder in the vagina or rectum. Cystometry can identify involuntary muscle contractions, indicate the level of pressure that causes urge incontinence, and measure the pressure required for the bladder to empty.

Electromyography examines the muscles of the bladder to assess its ability to coordinate impulses in the muscles of the bladder with impulses in the urinary sphincter. If these muscles are not coordinated, the process of normal urination is affected. Cystoscopy can also be performed, which involves running a tiny lens through the urethra to check for abnormalities such as tumors in the bladder.

How Is Overactive Bladder Treated?

Surgery to treat overactive bladder is only used on severe cases that do not respond to other treatments. Surgery may be performed to improve the storage ability of the bladder and reduce pressure. One type of surgical intervention is stimulation of specific nerves involved in bladder function. Stimulation of the nerves of the bladder is analogous to stimulation of the heart by a pacemaker. A thin nerve-stimulation wire attached to a small battery may be inserted under the skin.

See also Aging • Diabetes • Incontinence • Multiple Sclerosis (MS) • Neurogenic Bladder • Nocturia • Parkinson's Disease • Prostate Problems: Overview • Stroke


Books and Articles

Charnow, Jody A. (ed.) “OAB, SUI Worse after Vaginal Birth.” Renal and Urology News, April 29, 2014. http://www.renalandurologynews.com/urinary-incontinence/oab-sui-worse-after-vaginal-birth/article/344485/ (accessed October 26, 2015).

Hashim, Hashim, and Paul Abrams. Overactive Bladder Syndrome and Urinary Incontinence. Oxford, UK: Oxford University Press, 2012.

Terrie, Yvette C. “How to Cope with an Overactive Bladder.” U.S. News & World Report, July 7, 2014. http://health.usnews.com/health-news/health-wellness/articles/2014/07/07/how-to-cope-with-an-overactive-bladder (accessed October 26, 2015).


MedlinePlus. “Overactive Bladder.” U.S. National Library of Medicine, National Institutes of Health. https://www.nlm.nih.gov/medlineplus/overactivebladder.html (accessed November 24, 2015).

U.S. Food and Drug Administration. “Need Relief from Overactive Bladder Symptoms?” http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm426099.htm (accessed October 26, 2015).


American Urological Association. 1000 Corporate Blvd., Linthicum, MD 21090. Toll-free: 866-746-4282. Website: https://www.auanet.org (accessed October 26, 2015).

National Association for Continence. 1415 Stuart Engals Blvd., Mt Pleasant, SC 29464. Telephone: 843-377-0900. Website: http://www.nafc.org (accessed November 24, 2015).

* incontinence (in-KON-ti-nens) is loss of control of urination or bowel movement.

* Parkinson's disease is a disorder of the nervous system that causes shaking, rigid muscles, slow movements, and poor balance.

* stroke is a brain-damaging event usually caused by interference with blood flow to the brain. A stroke may occur when a blood vessel supplying the brain becomes clogged or bursts, depriving brain tissue of oxygen. As a result, nerve cells in the affected area of the brain, and the specific body parts they control, do not properly function.

* multiple sclerosis (skluh-ROsis) (or MS) is an inflammatory disease of the nervous system that disrupts communication between the brain and other parts of the body. MS can result in paralysis, loss of vision, and other symptoms.

* catheters (KAH-thuh-ters) are small plastic tubes placed through a body opening into an organ (such as the bladder) or through the skin directly into a blood vessel. They are used to give fluids to or drain fluids from a person.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)