The many possible causes of bedwetting

Lisa Shives, M.D., is the founder of Northshore Sleep Medicine in Evanston, Illinois. She blogs regularly on The Chart. Read more from her at Dr. Lisa Shives’ Sleep Better Blog.

Her parents were concerned that she had a serious medical or psychological problem, but the only thing that Lori cared about was being able to go to sleepovers without dying of embarrassment.

Lori was 9 years old and was still wetting the bed several times a week.

Bedwetting, known medically as sleep or nocturnal enuresis, is defined as involuntary voiding, or urination, during sleep that occurs at least twice a week after the age of 5. If the child has ever had a six-month period during which she was consistently dry, then she is said to have primary sleep enuresis.

If there was a six-month period of dryness, and yet bedwetting started again and lasted at least three months, then we call it secondary enuresis. The prevalence rates are higher in boys, but it is not uncommon in girls.

The traditional thinking has been that primary enuresis is more likely to be caused by a urologic disorder, but even in secondary enuresis, that is also always a consideration. Most important is the age of the child, how often the bedwetting is occurring, and whether there are signs and symptoms of other medical problems or psychosocial stressors.

For example, 10% of 6-year-olds still wet the bed at least twice a week and there is spontaneous cessation in about 15% of children per year. Therefore, I would have less concern about a child that age. One key question is whether the child has involuntary voiding while awake. If that is occurring often after the age of 5, then an organic, medical disorder is more likely. Also, in cases of primary enuresis, there is a strong hereditary factor.

One concern that many parents have is whether the bedwetting indicates a psychiatric or psychological problem. Psychosocial problems are not considered a common cause, although there is literature showing an increased rate of primary enuresis in children with attention-deficit/hyperactivity disorder and children living in disorganized families. Secondary enuresis occurs more commonly in children experiencing the stress of divorce or the trauma of physical or sexual abuse, or suffering from neglect.

Besides urinary tract infections and malformation of the genitourinary tract, there are several disorders that can cause or be associated with bedwetting.

The major disorders to consider are: 1) diabetes; 2) sickle cell disease; 3) malfunctioning of the hormone, vasopressin; 4) chronic constipation; 5) nocturnal seizures or other neurological disorders; 6) obstructive sleep apnea.

As a sleep physician, I am most concerned that parents and other physicians are aware of the connection to sleep apnea. There are many theories, and they are not mutually exclusive, as to why disordered breathing at night would cause involuntary voiding. Sleep apnea often causes confusional arousals and when stuck in a state between sleep and wake, urination may occur.

Repeated awakenings, even if they are so brief that the child does not remember, can disrupt the hormone vasopressin, also called antidiuretic hormone. When this hormone does not rise as it should, then the kidney keeps making urine during sleep and result can be bedwetting.

Another possibility is that sleep apnea in children is well known to be associated with stunted growth. Therefore, it could be that sleep apnea slows the neurologic development that is necessary for a child to sleep through the night without wetting the bed.

There is also an association between nocturia (frequent urination at night) and sleep apnea in older adults. The nocturia sometimes leads to bedwetting. I have so many older male patients who had been getting up to urinate five or six time a night and when we treat their sleep apnea and the trips to bathroom drop down to one or two, they are thrilled.

In Lucy’s case, she had “rough breathing” and sweating during the night and she had moderate-sized tonsils and so obstructive sleep apnea was suspected. Indeed, her sleep study showed significant disordered breathing at night with an elevation in her carbon dioxide for most of the night. Her parents and the ENT physician felt that a tonsillectomy/adenoidectomy was appropriate.

When I saw her two months after her operation, her sleep apnea had completely resolved and there had only been a couple of incidences of bedwetting as opposed to the nearly nightly occurrences before the sleep apnea was treated. Lucy is now happily attending sleepovers, free of worries of embarrassment, and is even going to go camping with her scout troop.

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