A study by Wake Forest Baptist Medical Center reveals that the cause for bedwetting is often constipation, and not always bladder problems. If left undiagnosed, bedwetting can be an unnecessarily long, expensive and difficult challenge to cure. The study is published online in the journal Urology.

The association between excess stool in the rectum (the lower 5-6 inches of the intestine) and bedwetting was first reported in 1986. The study involved 30 children aged between 5 to 15 years, old who sought treatment for bedwetting. The researchers found that although the majority had normal bowel habits, all 30 children has excess stool in their rectums. After laxative therapy, 83% (25 children) were cured of bedwetting within 3 months.

Lead researcher Steve J. Hodges, M.D., assistant professor of urology at Wake Forest Baptist, explained:

“Having too much stool in the rectum reduces bladder capacity. Our study showed that a large percentage of these children were cured of nighttime wetting after laxative therapy.

Parents try all sorts of things to treat bedwetting – from alarms to restricting liquids. In many children, the reason they don’t work is that constipation is the problem.”

According to Hodges, although the association was first reported in 1986, the finding did not result in a significant change in clinical practice, maybe because the definition of constipation is not standardized or uniformly understood by all physicians and lay people.

Hodges, explained:

“The definition for constipation is confusing and children and their parents often aren’t aware the child is constipated. In our study, X-rays revealed that all the children had excess stool in their rectums that could interfere with normal bladder function. However, only three of the children described bowel habits consistent with constipation.”

Current guidelines of the International Children’s Continence Society advise asking children and their patents if the consistency of the child’s stool is hard, and if their bowel movements occur irregularly (less often than every other day).

Hodges, said:

“These questions focus on functional constipation and cannot help identify children with rectums that are enlarged and interfering with bladder capacity. The kind of constipation associated with bedwetting occurs when children put off going to the bathroom. This causes stool to back up and their bowels to never be fully emptied. We believe that treating this condition can cure bedwetting.”

Study participants were first treated with polyethylene glycol (Miralax®) to clean out their bowel. Miralax works by causing the stool to retain water, thus softening it. Stimulate laxatives or enemas were used in children whose rectums remained enlarged after initial bowel clean out.

Hodges warned that any medical treatment for bedwetting should be supervised by a physician.

In order to identify children with excess stool in their rectums, the researched used abdominal X-rays. A special diagnostic method that involves measuring rectal size on the X-ray was developed by Hodges and radiologists at Wake Forest Baptist. Hodges explained that rectal ultrasound is another method that can be used for diagnosis.

Hodges, explained:

“The importance of diagnosing this condition cannot be overstated. When it is missed, children may be subjected to unnecessary surgery and the side effects of medications. We challenge physicians considering medications or surgery as a treatment for bedwetting to obtain an X-ray or ultrasound first.”

The researchers warned that some cases in their study may have improved on their own over time. They explain, in order to test the treatments success more accurately and identify true response from cases that would resolve over time, constipated children should be randomly assigned to receive either laxative therapy or an inactive therapy.

Hodges’ co-author on the study is Evelyn Y. Anthony, MD, a radiologist at Wake Forest Baptist.

Written by Grace Rattue