Definition of Urge incontinence:

Urge incontinence involves a strong, sudden need to urinate. Then the bladder contracts, leading to urine leakage.

Causes, incidence, and risk factors:

A person's ability to hold urine depends on normal function of the lower urinary tract, kidneys, and nervous system. The person must also have a physical and mental ability to recognize and respond to the urge to urinate.

The bladder's ability to fill and store urine requires a working sphincter muscle (which controls the flow of urine out of the body) and a stable bladder wall muscle (detrusor).

The process of urination involves two phases:

• Filling and storage
• Emptying

During the filling and storage phase, the bladder stretches so it can hold the increasing amount of urine. The bladder of an average person can hold 350 ml to 550 ml of urine. Generally, a person feels like they need to urinate when approximately 200 ml of urine fills up in the bladder.

The nervous system tells you that you need to urinate. It also allows the bladder to continue to fill.

The emptying phase requires the detrusor muscle to contract, forcing urine out of the bladder. The sphincter muscle must relax at the same time, so that urine can flow out of the body.

The bladder of an infant automatically contracts when a certain volume of urine is collected in the bladder. As the child grows older and learns to control urination, part of the brain (cerebral cortex) helps prevent bladder muscle contraction. This allows urination to be delayed until the person is ready to use the bathroom.

Undesired bladder muscle contractions may occur from nervous system (neurological) problems and bladder irritation.

URGE INCONTINENCE

Urge incontinence is leakage of urine due to bladder muscles that contract inappropriately. Often these contractions occur regardless of the amount of urine that is in the bladder.

Urge incontinence may result from:

• Bladder cancer
• Bladder inflammation
• Bladder outlet obstruction
• Bladder stones
• Infection
• Neurological diseases (such as multiple sclerosis)
• Neurological injuries (such as spinal cord injury or stroke)

In men, urge incontinence also may be due to:

• Bladder changes caused by benign prostatic hypertrophy (BPH)
• Bladder outlet obstruction from an enlarged prostate

In most cases of urge incontinence, no specific cause can be identified.

Although urge incontinence may occur in anyone at any age, it is more common in women and the elderly.