Urinary Incontinence in Children.

In the United States, at least 13 million people have problems holding urine until they can get to a toilet. This loss of urinary control is called "urinary incontinence" or just "incontinence." Although it affects many young people, it usually disappears naturally over time, which suggests that incontinence, for some people, may be a normal part of growing up. No matter when it happens or how often it happens, incontinence causes great distress. It may get in the way of a good night's sleep and is embarrassing when it happens during the day. That's why it is important to understand that occasional incontinence is a normal part of growing up and that treatment is available for most children who have difficulty controlling their bladders.

How Does the Urinary System Work?

Urination, or voiding, is a complex activity. The bladder is a balloonlike muscle that lies in the lowest part of the abdomen. The bladder stores urine, then releases it through the urethra, the canal that carries urine to the outside of the body. Controlling this activity involves nerves, muscles, the spinal cord, and the brain.

The bladder is made of two types of muscles: the detrusor, a muscular sac that stores urine and squeezes to empty, and the sphincter, a circular group of muscles at the bottom or neck of the bladder that automatically stay contracted to hold the urine in and automatically relax when the detrusor contracts to let the urine into the urethra. A third group of muscles below the bladder (pelvic floor muscles) can contract to keep urine back.

A baby's bladder fills to a set point, then automatically contracts and empties. As the child gets older, the nervous system develops. The child's brain begins to get messages from the filling bladder and begins to send messages to the bladder to keep it from automatically emptying until the child decides it is the time and place to void.

Failures in this control mechanism result in incontinence. Reasons for this failure range from the simple to the complex.

Incontinence happens less often after age 5: About 10 percent of 5-year-olds, 5 percent of 10-year-olds, and 1 percent of 1 g-year-olds experience episodes of incontinence. It is twice as common in boys as in girls.

What Causes Nighttime Incontinence?

After age 5, wetting at night--often called bedwetting or sleepwetting--is more common than daytime wetting in boys. Experts do not know what causes nighttime incontinence. Young people who experience nighttime wetting tend to be physically and emotionally normal. Most cases probably result from a mix of factors including slower physical development, an overproduction of urine at night, a lack of ability to recognize bladder filling when asleep, and, in some cases, anxiety. For many, there is a strong family history of bedwetting, suggesting an inherited factor.

Slower Physical Development

Between the ages of 5 and 10, incontinence may be the result of a small bladder capacity, long sleeping periods, and underdevelopment of the body's alarms that signal a full or emptying bladder. This form of incontinence will fade away as the bladder grows and the natural alarms become operational.

Excessive Output of Urine During Sleep

Normally, the body produces a hormone that can slow the making of urine. This hormone is called antidiuretic hormone, or ADH. The body normally produces more ADH at night so that the need to urinate is lower. If the body doesn't produce enough ADH at night, the making of urine may not be slowed down, leading to bladder overfilling. If a child does not sense the bladder filling and awaken to urinate, then wetting will occur.

Anxiety

Experts suggest that anxiety-causing events occurring in the lives of children ages 2 to 4 might lead to incontinence before the child achieves total bladder control. Anxiety experienced after age 4 might lead to wetting after the child has been dry for a period of 6 months or more. Such events include angry parents, unfamiliar social situations, and overwhelming family events such as the birth of a brother or sister.

Incontinence itself is an anxiety-causing event. Strong bladder contractions leading to leakage in the daytime can cause embarrassment and anxiety that lead to wetting at night.

Genetics

Certain inherited genes appear to contribute to incontinence. In 1995, Danish researchers announced they had found a site on human chromosome 13 that is responsible, at least in part, for nightime wetting. If both parents were bedwetters, a child has an 80 percent chance of being a bedwetter also. Experts believe that other, undetermined genes also may be involved in incontinence.

Structural Problems

Finally, a small number of cases of incontinence are caused by physical problems in the urinary system in children. Rarely, a blocked bladder or urethra may cause the bladder to overfill and leak. Nerve damage associated with the birth defect spina bifida can cause incontinence. In these cases, the incontinence can appear as a constant dribbling of urine.

What Causes Daytime Incontinence?

Daytime incontinence that is not associated with urinary infection or anatomic abnormalities is less common than nighttime incontinence and tends to disappear much earlier than the nighttime versions. One possible cause of daytime incontinence is an overactive bladder. Many children with daytime incontinence have abnormal voiding habits, the most common being infrequent voiding.

An Overactive Bladder

Muscles surrounding the urethra (the tube that takes urine away from the bladder) have the job of keeping the passage closed, preventing urine from passing out of the body. If the bladder contracts strongly and without warning, the muscles surrounding the urethra may not be able to keep urine from passing. This often happens as a consequence of urinary tract infection and is more common in girls.

Infrequent Voiding

Infrequent voiding refers to a child's voluntarily holding urine for prolonged intervals. For example, a child may not want to use the toilets at school or may not want to interrupt enjoyable activities, so he or she ignores the body's signal of a full bladder. In these cases, the bladder can overfill and leak urine. Additionally, these children often develop urinary tract infections (UTIs), leading to an irritable or overactive bladder.

Other Causes

Some of the same factors that contribute to nighttime incontinence mayact together with infrequent voiding to produce daytime incontinence. These factors include

* A small bladder capacity

* Structural problems

* Anxiety-causing events

* Pressure from a hard bowel movement (constipation)

* Ingestion of bladder irritants such as caffeine and aspartame (an artificial sweetener).

Sometimes overly strenuous toilet training may make the child unable to relax the sphincter and the pelvic floor to completely empty the bladder. Retaining urine (incomplete emptying) sets the stage for urinary tract infections.

What Treats or Cures Cures Incontinence?

Growth and Development

Most urinary incontinence fades away naturally. Here are examples of what can happen over time:

* Bladder capacity increases.

* Natural body alarms become activated.

* An overactive bladder settles down.

* Production of ADH becomes normal.

* The child learns to respond to the body's signal that it is time to void.

* Stressful events or periods pass.

Many children overcome incontinence naturally (without treatment) as they grow older. The number of cases of incontinence goes down by 15 percent for each year after the age of 5.

Medications

Nighttime incontinence may be treated by increasing ADH levels. The hormone can be boosted by a synthetic version known as desmopressin, or DDAVP. Users, including children, spray a mist containing desmopressin into their nostrils, where the drug enters the bloodstream. Researchers are developing a pill version of this drug.

Another medication, called imipramine, is also used to treat sleepwetting. It acts on both the brain and the urinary bladder. Unfortunately, total dryness with either of the medications available is achieved in only about 20 percent of patients.

If a young person experiences incontinence resulting from an overactive bladder, a doctor might prescribe a medicine that helps to calm the bladder muscle. This medicine controls muscle spasms and belongs to a class of medications called anticholinergics.

Bladder Training and Related Strategies

Bladder training consists of exercises for strengthening and coordinating muscles of the bladder and urethra, and may help the control of urination. These techniques teach the child to anticipate the need to urinate and prevent urination when away from a toilet. Techniques that may help nighttime incontinence include

* Determining bladder capacity

* Stretching the bladder (delaying urinating)

* Drinking less fluid before sleeping

* Developing routines for waking up.

Unfortunately, none of the above has demonstrated proven success.

Techniques that may help daytime incontinence include

* Urinating on a schedule, such as every 2 hours (this is called timed voiding)

* Avoiding caffeine and the artificial sweetener aspartame

* Following suggestions for healthy urination, such as relaxing muscles and taking your time.

Moisture Alarms

At night, moisture alarms can wake a person when he or she begins to urinate. These devices include a water-sensitive pad worn in pajamas, a wire connecting to a battery driven control, and an alarm that sounds when moisture is first detected. For the alarm to be effective, the child must awaken or be awakened as soon as the alarm goes off. This may require having another person sleep in the same room to awaken the bedwetter.

Incontinence is also called enuresis.

* Primary enuresis refers to wetting in a person who has never been dry for at least 6 months.

* Secondary enuresis refers to wetting that begins after at least 6 months of dryness.

* Nocturnal enuresis refers to wetting that usually occurs during sleep (nighttime incontinence).

* Diurnal enuresis refers to wetting when awake (daytime incontinence).

Points to Remember

* Urinary incontinence in children is common.

* Nighttime wetting occurs more commonly in boys.

* Daytime wetting is more common in girls.

* After age 5, incontinence disappears naturally at a rate of 15 percent of cases per year.

* Treatments include waiting, dietary modification, moisture alarms, medications, and bladder training.

Additional Resources

American Foundation for Urologic Disease
300 West Pratt Street
Suite 401
Baltimore, MD 21201
(Responds to written requests for patient information)

National Association For Continence
P.O. Box 8310
Spartanburg, SC 29305
(800) BLADDER or [phone]

National Kidney Foundation
30 East 33rd Street
New York, NY 10016
[phone] or [phone]

The Simon Foundation for Continence
P.O. Box 835
Wilmette, IL 60091
(800) 23-SIMON

Society for Urologic Nurses and Associates
P.O. Box 56
East Holly Avenue
Pitman, NJ 08071
[phone]

National Kidney and Urologic Diseases Information Clearinghouse

3 Information Way
Bethesda, MD 20892-3580
E-mail: [e-mail]

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NIH Publication No. 97-4095 March 1997

e-text posted: 12 February 1998