Incontinence can affect people of all ages, although the reasons for childhood and adult incontinence are different. The most common types of incontinence in adults are stress incontinence, associated with weakened muscle support and bladder control triggered by childbirth or old age, and urge (or urgency) incontinence, the condition in which patients need to urinate frequently. Mixed incontinence is both problems combined.
Urinary incontinence is a symptom of various conditions rather than a disease itself. There are three major types of urinary incontinence: (1) In [sphincter incontinence], the muscular sphincter which is the outlet of the bladder fails to keep the opening tightly closed. Leakage can occur either intermittently or continuously. [Stress incontinence] is the most common type of sphincter-related urine leakage and generally results from a loss of normal pelvic support of the sphincter area. Stress incontinence occurs during sneezing, coughing, physical exertion, or any activity that increases intra-abdominal pressure. It is most common in females - especially elderly women. Rarer is the condition of people with a nonfunctional bladder outlet - one that is never capable of functioning as a sphincter. Such individuals either leak urine continuously or with the slightest provocation, such as changing positions. This type of sphincter incontinence is generally due to damage to the structures that are part of the sphincter or the neural supply to the sphincter. (2) [Urge (urgency) incontinence] is the involuntary loss of urine (a small or large amount) following a sudden, strong desire to urinate (urgency). This disorder is often associated with neurologic disease such as stroke, senile dementia, Parkinson's disease and multiple sclerosis but may also be seen in individuals without such disease. Bladder-related incontinence may result from an uncontrollable urge to void to relieve pain that occurs as the bladder fills. (3) Finally, so-called [overflow urinary incontinence] refers to the leakage of urine from a full bladder. This commonly occurs in older men whose flow of urine from the bladder is blocked by an enlarged prostate.
There are many causes of urinary incontinence. Some of these causes are related to temporary conditions. Once they are treated, the incontinence usually goes away. Temporary causes include: urinary tract infection, constipation, certain medications, and increased dietary intake of caffeine, alcohol, artificial sweeteners and carbonated beverages.
Some other causes of incontinence are not temporary. Other causes include: weakness of the muscles that hold the bladder in place; weakness of the bladder and or the sphincter muscles; overactive or underactive bladder muscles; decreases in certain hormones, especially oestrogen; and neurological disorders (eg multiple sclerosis, Parkinson's disease).