Broadly speaking, the medical term incontinence refers to any involuntary release of bodily fluids, but many people associate it strongly with the inability to control urine flow. There are actually several different forms: fecal, urinary, and in some cases, seminal. Physicians would be most likely to define a patient's condition as "fecal incontinence" or "urinary stress incontinence." Some may actually have a condition called "mixed incontinence," a combination of both fecal and urinary difficulties.
Urinary incontinence occurs when the sphincter muscles at the base of the bladder fail to hold back the flow of urine. In healthy people, these sphincter muscles remain rigid until the urge to urinate becomes too strong to ignore. The bladder receives and stores urine from the kidneys until it reaches a certain capacity, generally around 8 fluid ounces (236.5 ml). At this point, healthy people should feel the first signal to urinate. The bladder can continue to store urine until around 16 fluid ounces (473.1 ml), when urination becomes a necessity.
Under normal circumstances, this signal to urinate is followed by a compression of the bladder wall muscles and a relaxation of the sphincter muscles. The urine flows into the urethra and eventually out of the body. People suffering from urinary incontinence, however, may not be able to void (empty) all of their urine in one sitting, leaving some in the bladder itself. This may signal the sphincter muscles to relax involuntarily, causing a urinary leak.
This continuous cycle of voiding a partially-empty bladder is called urge incontinence. This condition is very common among women who are pregnant or have difficulty reaching the bathroom in time. Elderly people also tend to develop it as a result of the aging process or surgical procedures. Men without prostate glands may also experience a form of urge incontinence.
The other common form is called stress incontinence. Anyone who has experienced involuntary leaks of urine after laughing or coughing has experienced this condition. Pregnancy can also trigger a bout of it as the uterus and other organs press down on the bladder. Many sufferers wear protective garments to minimize the effects of accidents.
Incontinence is often just one symptom of a much larger medical condition. Urinary tract infections can cause temporary urge incontinence, as can the removal of catheters following surgery. Medical professionals can prescribe medication for overactive bladders that attempt to control the contractions of the bladder muscles. Bouts of incontinence, either fecal or urinary, should be reported to a healthcare provider as soon as possible, as they could be an indication of a much more serious disease.