Bed-wetting, also called enuresis, is the unintentional discharge of urine during sleep. Although most children between the ages of three and five begin to stay dry at night, the age at which children are physically and emotionally ready to maintain complete bladder control varies.
Most children wet the bed occasionally, and definitions of the age and frequency at which bed-wetting becomes a medical problem vary somewhat. The word enuresis is derived from a Greek word meaning "to make water." Enuresis is defined as the repeated voiding of urine into the bed or clothes at least twice a week for at least three consecutive months in a child who is at least five years of age. It can be nocturnal
Enuresis is divided into two classes. A child with primary enuresis has never been consistently dry through the night. A child with secondary enuresis begins to wet after a prolonged dry period. Some children have both nocturnal and diurnal enuresis.
The prevalence of bedwetting gradually declines throughout childhood. Of children aged five years, 23 percent have nocturnal enuresis. During elementary school years, the problem remains common, with 20 percent of seven-year-old children and 4 percent of ten-year-old children still experiencing nighttime bedwetting. Nocturnal enuresis is more common in males. It occurs in boys aged seven and ten years at 9 percent and 7 percent, respectively, compared to 6 percent and 3 percent, respectively, in girls.
Causes and symptoms
The causes of bed-wetting are not entirely known. It tends to run in families. Most children with primary enuresis have a close relative—a parent, aunt, or uncle—who also had the disorder. Over 70 percent of children with two parents who wet the bed will also wet the bed. Twin studies have shown that both of a pair of identical twins experience enuresis more often than both of a pair of fraternal twins.
Sometimes bed-wetting can be caused by a serious medical problem like diabetes, sickle-cell anemia, or epilepsy. Snoring and episodes of interrupted breathing during sleep (sleep apnea) occasionally contribute to bed-wetting problems. Enlarged adenoids can cause these conditions. Other physiological problems, such as urinary tract infection, severe constipation, or spinal cord injury, can cause bed-wetting.
Children who wet the bed frequently may have a smaller than normal functional bladder capacity. Functional bladder capacity is the amount of urine a person can hold in the bladder before feeling a strong urge to urinate. When functional capacity is small, the bladder will not hold all the urine produced during the night. Tests have shown that bladder size in these children is normal. Nevertheless, they experience frequent strong urges to urinate. Such children urinate often during the daytime and may wet several times at night. Although a small functional bladder capacity may be caused by a developmental delay, it may also be that the child's habit of voiding frequently slows bladder development.
Parents often report that their bed-wetting child is an extremely sound sleeper and difficult to wake. However, several research studies found that bed-wetting children have normal sleep patterns and that bed-wetting can occur in any stage of sleep.
In the early 2000s medical research has found that many children who wet the bed may have a deficiency of an important hormone known as antidiuretic hormone (ADH). ADH helps to concentrate urine during sleep hours, meaning that the urine contains less water and, therefore, takes up less space. This decreased volume of water usually prevents the child's bladder from overfilling during the night, unless the child drinks a lot just before going to bed. Testing of many bed-wetting children has shown that these children do not have the usual increase in ADH during sleep. Children who wet the bed, therefore, often produce more urine during the hours of sleep than their bladders can hold. If they do not wake up, the bladder releases the excess urine and the child wets the bed.
Research demonstrates that in most cases bedwetting does not indicate that the child has a physical or psychological problem. Children who wet the bed usually have normal-sized bladders and have sleep patterns that are no different from those of non-bedwetting children. Sometimes emotional stress, such as the birth of a sibling, a death in the family, or separation from the family, may be associated with the onset of bed-wetting in a previously toilet-trained child. Daytime wetting, however, may indicate that the problem has a physical cause.
While most children have no long-term problems as a result of bed-wetting, some children may develop psychological problems. Low self-esteem may occur when these children, who already feel embarrassed, are further humiliated by angry or frustrated parents who punish them or who are overly aggressive about toilet training. The problem can by aggravated when playmates tease or when social activities such as sleep-away camp are avoided for fear of teasing.
When to call the doctor
Parents should contact their child's doctor if the child has started wetting the bed after a sustained period of time staying dry. Parents should also notify the physician if their child over the age of five begins to have urinary incontinence during the day, as this may be caused by a physical disorder.
If a child continues to wet the bed after the age of six, parents may feel the need to seek evaluation and diagnosis by the family doctor or a children's specialist (pediatrician). Typically, before the doctor can make a diagnosis, a thorough medical history is obtained. Then the child receives a physical examination, appropriate laboratory tests, including a urine test, and if necessary, radiologic studies (such as x rays).
If the child is healthy and no physical problem is found, which is the case 90 percent of the time, the doctor may not advise treatment but rather may provide the parents and the child with reassurance, information, and advice.
Occasionally a doctor will determine that the problem is serious enough to require treatment. Standard treatments for bed-wetting include bladder training exercises, motivational therapy, drug therapy, psychotherapy, and diet therapy.
Bladder training exercises are based on the theory that those who wet the bed have small functional bladder capacity. Children are told to drink a large quantity of water and to try to prolong the periods between voiding. These exercises are designed to increase bladder capacity but are only successful in resolving bed-wetting in a small number of patients.
In motivational therapy, parents attempt to encourage the child to combat bed-wetting, but the child must want to achieve success. Positive reinforcement, such as praise or rewards for staying dry, can help improve self-image and resolve the condition. Punishment for wet nights hamper the child's self-esteem and compound the problem.
The following motivational techniques are commonly used:
- Behavior modification: This method of therapy is aimed at helping children take responsibility for their nighttime bladder control by teaching new behaviors. For example, children are taught to use the bathroom before bedtime and to avoid drinking fluids after dinner. While behavior modification generally produces good results, it is long-term treatment.
- Alarms: This form of therapy uses a sensor placed in the child's pajamas or in a bed pad. This sensor triggers an alarm that wakes the child at the first sign of wetness. If the child is awakened, he or she can then go to the bathroom and finish urinating. The intention is to condition a response to awaken when the bladder is full. Bed-wetting alarms require the motivation of both parents and children. They were considered the most effective form of treatment available as of 2004.
A number of drugs are also used to treat bedwetting. These medications are usually fast acting; children often respond to them within the first week of treatment. Among the drugs commonly used are a nasal spray of desmopressin acetate (DDAVP), a substance similar to the hormone that helps regulate urine production; and imipramine hydrochloride, a drug that helps to increase bladder capacity. Studies show that imipramine is effective for as many as 50 percent of patients. However, children often wet the bed again after the drug is discontinued, and it has some side effects. Some bed-wetting with an underlying physical cause can be treated by surgical procedures. These causes include enlarged adenoids that cause sleep apnea, physical defects in the urinary system, or a spinal tumor.
Psychotherapy is indicated when the child exhibits signs of severe emotional distress in response to events such as a death in the family, the birth of a new child, a change in schools, or divorce. Psychotherapy is also indicated if a child shows signs of persistently low self-esteem or depression.
In rare cases, allergies or intolerances to certain foods—such as dairy products, citrus products, or chocolate—can cause bed-wetting. When children have food sensitivities, bed-wetting may be helped by discovering the substances that trigger the allergic response and eliminating these substances from the child's diet.
Occasional bed-wetting is not a disease, and it does not have a cure. If the child has no underlying physical or psychological problem that is causing the bed-wetting, in most cases he or she will outgrow the condition without treatment. About 15 percent of bedwetters become dry each year after age six. If bedwetting is frequent, accompanied by daytime wetting, or falls into the American Psychiatric Association's diagnostic definition of enuresis, a doctor should be consulted. If treatment is indicated, it usually successfully resolves the problem. Marked improvement is seen in about 75 percent of cases treated with wetness alarms.
Although preventing a child from wetting the bed is not always possible, parents can take steps to help the child keep the bed dry at night. These steps include:
- encouraging and praising the child for staying dry instead of punishing when the child wets
- reminding the child to urinate before going to bed, if he or she feels the need
- limiting liquid intake at least two hours before bedtime
Bed-wetting often leads to behavioral problems because of the embarrassment and guilt the child may feel. Parents should not attempt to make their child feel guilty about wetting the bed. They should let the child know that bedwetting is not their fault. Punishment is an inappropriate response to enuresis and will not resolve the problem.
Nocturnal enuresis—Involuntary discharge of urine during the night.
Void—To empty the bladder.
Mercer, Renee. Seven Steps to Nighttime Dryness: A Practical Guide for Parents of Children with Bedwetting. New York: Brookville Media: 2003.
"Summary of the Practice Parameter for the Assessment and Treatment of Children and Adolescents with Enuresis." Journal of the American Academy of Child and Adolescent Psychiatry 43 (January 2004): 1, 123–125.
National Kidney Foundation. 30 East 33rd St., New York, NY 10016. Web site: <http://kidney.org>.
"Enuresis (Bed-wetting)." FamilyDoctor.org, October 2003. Available online at <http://familydoctor.org/366.xml> (accessed January 11, 2005).
Deanna M. Swartout-Corbeil, RN Genevieve Slomski, Ph.D.