Overactive Bladder (OAB)

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2. Urinary Incontinence in Men Slideshow Pictures
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Medical Author:

Siamak T. Nabili, MD, MPH

Siamak T. Nabili, MD, MPH

Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.

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Medical Editor:

Dennis Lee, MD

Dennis Lee, MD

Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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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.

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).