Nocturnal Enuresis (Bedwetting) - Causes, Symptoms and Treatment

Bedwetting, also known as nocturnal enuresis, is the accidental or involuntary release of urine during sleep. Bedwetting is a common problem among children, even after they have been toilet-trained.
Most children gradually stop wetting the bed on their own as they grow older. Usually, children stop wetting the bed between 3 and 5 years of age. Bedwetting is considered a problem if the child is over age 5 and continues to wet the bed two or more times a week for at least three months in a row.

Although bedwetting is not a serious condition, it can cause stress for the child and family. Children who wet the bed may feel ashamed or embarrassed. They might avoid taking part in activities, such as sleepovers or camping, because they are worried that they might wet the bed while they’re away from home.
There are two main types of bedwetting — primary and secondary nocturnal enuresis:

• Primary nocturnal enuresis is a condition in which the person has never remained dry throughout the night for 6 months in a row or longer.
• Secondary nocturnal enuresis is a condition in which the child has started wetting the bed again after not wetting the bed for 6 months or more. Secondary enuresis is more likely to be caused by a medical problem or psychological condition.

Diurnal enuresis is a condition in which a child cannot hold his or her urine at any time of the day or night. This is more common among younger children.

How common is bedwetting?

About 5 million children in the United States wet their beds. It happens more often among younger children. About 2-3% of people over 18 have primary nocturnal enuresis. Bedwetting occurs more often among boys.

What causes bedwetting?

Usually, there is no medical or psychological condition that causes bedwetting (a small percentage of children who wet the bed do have a medical condition). Bedwetting can be caused by many things, including:

• Family history: Children with a parent or parents who were bedwetters are more likely to wet the bed.
• Constipation: Pressure from extra stool inside the rectum may interfere with the nerve signals that the bladder sends to the brain. A full rectum can also reduce the amount of urine that the bladder can hold or prevent it from emptying completely during urination.
• Hormones: A hormone called vasopressin limits the volume of urine that the body produces during the night. Vasopressin works by causing water in urine to be reabsorbed by the bloodstream, so a smaller volume of urine enters the bladder. Children who do not produce enough vasopressin might be more likely to wet the bed.
• Small functional bladder capacity: Children with small functional bladder capacity have normal-sized bladders, but they sense that their bladders are full even when the bladder can still hold more urine. They tend to urinate more often during the day and might have a sudden urge to run to the bathroom to prevent an accident. They also are more likely to wet the bed during the night.
• Failure to awaken during the night - Sometimes children are unable to wake up in time to get to the bathroom. As the bladder fills with urine, it sends a signal to the brain, which sends a signal back to the bladder to relax so it can hold more urine. A full bladder continues to send signals to the brain so that the child will awaken. Bedwetting occurs when the child has not yet learned to respond to these internal signals.
• Psychological or emotional problems - Emotional stress caused by traumatic events or disruptions in a child’s normal routine can cause bedwetting. For example, moving to a new home, enrolling in a new school, or the death of a loved one may set off bedwetting episodes that become less frequent over time.
• Sexual abuse - Children who begin wetting the bed again after they have learned to stay dry may be victims of sexual abuse. Other signs of abuse include frequent urinary tract infections, vaginal pain, itching or an unusual discharge, or a sexually transmitted disease.
• Medical conditions - Disorders that are associated with bedwetting include urinary tract infections, diabetes, sickle cell disease, and sleep apnea. Neurological problems or kidney or bladder abnormalities may also be causes. If bedwetting recurs after your child has been dry for 6 months or more, a medical condition may be causing it.

How is bedwetting diagnosed?

In most cases, the child’s pediatrician will be able to determine whether or not there is a medical condition that is causing the bedwetting by taking a detailed medical history and performing a physical examination. The doctor may request a urine sample to rule out a urinary tract infection.
If your doctor suspects that the bedwetting is due to a medical disorder, he or she probably will order blood tests or a radiological exam.

How is bedwetting treated?

If there is no medical cause for bedwetting, your doctor can provide tips on managing the condition. Bedwetting can be treated by changing the child’s behavior or with various oral (taken by mouth) medications.
Behavioral techniques include:

• Limiting fluids before bedtime - Don’t give your child anything to drink at least two hours before bedtime. Make sure your child drinks plenty of fluids during the day.
• Going to the bathroom before bedtime - Make sure your child goes to the bathroom and empties his or her bladder completely before going to bed.
• Enuresis alarm - This is an electrical device that makes a loud noise or vibrates to awaken the child when he or she starts to wet the bed. It has a wetness sensor that sets off the alarm so that the child can wake up and finish urinating in the bathroom. Over time, the child learns to wake up when he or she feels the sensation of a full bladder, and eventually might be able to sleep through the night without having to urinate. This technique may take several months to produce results.
• Nighttime waking - Parents sometimes find it helpful to awaken their child a few hours after bedtime and take him or her to the bathroom. One problem with this method is that it trains the child to awaken at a certain time each night, without teaching him or her to recognize the internal signals associated with a full bladder.
• Bladder therapy - This approach is aimed at gradually increasing the bladder’s functional capacity by making the child wait to go to the bathroom. Increasing the length of time between bathroom visits helps enlarge the bladder to allow it to hold more urine.
• Counseling - Psychological counseling may be effective in cases where the child has had a traumatic event or is suffering from low self-esteem because of the bedwetting.

Medications

The following medications may be used alone or in combination with behavioral techniques to treat bedwetting:

• Desmopressin - This is the man-made version of the hormone vasopressin, which causes the kidneys to produce less urine. It is effective in about half of all cases, with better results in older children who have normal bladder capacity. The drug can lower sodium levels in children who take it, so parents should limit the amount of fluids their child drinks after dinner. This is the most common medication prescribed to help control bedwetting.
• Oxybutinin - This medication is used to treat overactive bladder by reducing bladder contractions. It is generally used along with desmopressin or the enuresis alarm method. It may be effective for children who wet the bed more than once each night and who also have daytime wetting.
• Imipramine - This drug is effective in 40% of cases, but it must be used with caution because of the risk of serious side effects.

References

• National Kidney and Urologic Diseases Information Clearinghouse. Urinary Incontinence in Children. kidney.niddk.nih.gov Accessed 7/25/2012
• UpToDate. Patient information: Bedwetting in children (Beyond the Basics). www.uptodate.com Accessed 7/25/2012
• National Kidney and Urologic Diseases Information Clearinghouse What I need to know about My Child’s Bedwetting. kidney.niddk.nih.gov Accessed 7/25/2012 

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