Urinary incontinence is the involuntary leakage of urine. Although it becomes more common as people get older, incontinence is not normal at any age. Many types of therapy are available for urinary incontinence. A brief review of the normal process of urination in adults will help in understanding both the causes and treatment of urinary incontinence.
NORMAL URINATION — Urine is produced by the kidneys and passes into a muscular sac called the urinary bladder. The urethra is the tube that leads from the bladder to the outside of the body
A ring of muscles, called the urinary sphincter, surrounds the urethra. As the bladder fills with urine, complex nerve signals ensure that the sphincter muscles are contracted and the bladder muscle stays relaxed. This allows the bladder to fill with urine and prevents urine from leaking out.
When the bladder is nearing full, nerve signals are sent to the brain, letting the person know that the bladder is getting full. Additional nerve signals must be sent to begin urination. Some of these signals cause the bladder muscles to contract, which pushes urine into the urethra. At the same time, other signals cause the sphincter muscles to relax, which allows the urine to pass out of the body. Most individuals empty their bladder every three to five hours during the day and zero to one times during the night.
Simply put, four things can go wrong with this process:
The bladder contracts when the person is not ready to urinate, called urge incontinence. This is the most common reason people have incontinence.
The sphincter does not close properly or does not stay closed when there is increased pressure (as with a cough or sneeze), allowing urine to leak. This is called stress incontinence, and is a common reason for incontinence in women, especially women who have had children.
The bladder is too weak to empty completely, causing leakage when the bladder is overly full. This is called overflow incontinence, and is uncommon.
The urethra is obstructed, preventing urine from draining completely, which can also lead to overflow incontinence. This is common in men with an enlarged prostate.
Urine leakage also can occur when persons are unable to make it to the toilet on time when medical conditions, medications, and/or difficulty with thinking and immobility interfere with normal bladder and sphincter function and getting to a bathroom.
RISK FACTORS
The frequency of urinary incontinence increases with age, and it affects more women than men. About 10 to 30 percent of women and 1.5 to 5 percent of men up to age 64 have urinary incontinence. In those age 65 and older, 15 to 30 percent of individuals have incontinence. At least 50 percent of persons older than 65 who live in long-term care facilities (eg, nursing homes) have incontinence [1].
Urinary incontinence also has been associated with a number of conditions, including obesity (in women), high impact physical activities, heart failure, lung problems, smoking, chronic cough, depression, constipation, pregnancy, vaginal delivery, and problems with mobility.
TYPES OF URINARY INCONTINENCE
Urge incontinence
Urge incontinence occurs when the bladder contracts suddenly, so that a normal "urge" becomes more forceful "urgency", the strong, uncomfortable need to urinate. A person with urge incontinence will generally have an abrupt, overwhelming urge to urinate, followed by urine leakage that can range from a few drops to soaking. The urgency and leakage may occur in response to a stimulus, such as unlocking the door when returning home, going out in the cold, turning on the faucet, or washing hands.
There are many names that have been used for urge incontinence and the associated symptoms of urgency and frequency, including overactive bladder, detrusor instability or overactivity, and irritable or spastic bladder.
Some patients with overactive bladder have symptoms of urinary urgency and frequency during the daytime only, while other patients also have to urinate frequently during the night (called nocturia). Frequency is the complaint of needing to urinate more often than other people (normal is considered to be 8 times in 24 hours).
Factors that can lead to urge incontinence include age-related changes in the anatomy of the urinary tract and the physiology of urination, nervous system problems related to conditions such as stroke, or bladder irritation caused by inflammation.
Stress incontinence
Stress incontinence occurs when the urinary sphincter does not stay closed during an increase in pressure in the abdomen, leading to urine leakage. As an example, the increased pressure in the abdomen with coughing, sneezing, laughing, or running can cause episodes of stress incontinence in susceptible patients. Stress incontinence is the most common cause of urinary incontinence in younger women, the second most common cause in older women, and may occur in older men after certain types of prostate surgery.
Stress incontinence in women is most commonly caused by weakness in the muscles and other tissues that support the urethra. Less commonly, stress incontinence is caused by complete failure of the sphincter to close, a condition known as intrinsic sphincter deficiency (ISD). This can occur due to scarring from surgery or radiation therapy used for cancer treatment.
Mixed incontinence
Mixed incontinence is the combination of both urge and stress incontinence, and is most common in younger to middle aged women.
Incontinence associated with medical factors
Urinary incontinence can occur due to treatable factors and medical conditions (show table 1A-1B). As examples, medical conditions such as urinary tract infection or poorly-controlled diabetes may temporarily cause urinary leakage. Certain medications, excess fluid intake, fluid retention, and arthritis or other problems that cause difficulty in getting to the toilet are potentially treatable causes of incontinence.
Overflow incontinence
Overflow incontinence refers to leakage that occurs when the bladder fails to empty properly, either because of obstruction of the urethra or weak bladder muscle contractions. When the person tries to urinate, abnormally large amounts of urine remain in the bladder. There may be a weak stream, dribbling, and frequent urination. An element of stress incontinence may occur at the same time.
Overflow incontinence is relatively uncommon, but can occur in some older men in whom either benign or cancerous enlargement of the prostate (a gland that surrounds the urethra) causes marked narrowing of the urethra. It is uncommon in women.
DIAGNOSIS —
One of the most important first steps in the diagnosis and treatment of urinary incontinence is for the patient to openly and honestly discuss their problem with a healthcare provider. Studies have shown that up to one-half of persons with incontinence do not discuss their problem with a healthcare professional. However, disclosing the problem to a clinician can lead to an accurate diagnosis and effective treatment.
A number of tools are available to help determine the cause of urinary incontinence.
History and physical examination — The history and physical examination are among the most important steps in the investigation and treatment of urinary incontinence. Patients should discuss the type of leakage (associated with urgency, increases in abdominal pressure, or without warning), when their leakage began, if it has worsened or improved over time, and if they have tried any self-management techniques or prescribed treatments. Patients should also mention if they have a problem with leakage of stool (fecal incontinence). A full physical examination includes a review of mental status (alert versus confused), nerve and heart function, genital or pelvic exam, and a rectal examination, all of which can provide clues about the cause(s) of incontinence.
Bladder diary — Patients may be asked to keep a bladder diary to measure the timing and amount of urine voided, frequency and amount of leakage, and any associated factors, such as coughing or sneezing. This provides useful information about the cause(s) and potential treatment of incontinence.
Office tests — Simple tests may be done during an office visit to determine the type of leakage a patient has, which can help to guide treatment decisions. The provider may ask the patient to cough vigorously to determine if leakage occurs (usually as a result of stress incontinence). They may measure the amount of urine left in the bladder after normal urination to determine how well the bladder empties; this is called the post void residual, and should be less than 50 cc (approximately 2 ounces). This can be done by inserting a catheter into the bladder after the patient voids, or by using a type of ultrasound (called a bladder scanner).
Laboratory tests — The clinician will request a urine test (urinalysis) to look for evidence of infection or blood in the urine. Blood tests may be ordered to measure the kidney function.
Urodynamic testing — Urodynamic testing examines the bladder, urethra, and urethral sphincter as the bladder is filled with water, when the bladder is full, and when the person coughs or bears down. Testing includes measurement of the bladder capacity (how much the bladder can hold), the pressures in the bladder and urethra, and how fast urine flows during urination. Urodynamic testing is not needed for all persons with incontinence, but may be recommended in certain situations, such as to confirm stress incontinence if surgery is planned.
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