Marilyn W. Edmunds, PhD, NP


May 03, 2001


What can you do for a child with encopresis (involuntary defecation) that is not responding to either the use of the laxative, MiraLax (polyethylene glycol), at high doses or the use of a bowel regimen?

Response from Marilyn W. Edmunds, PhD, NP

These kids can be so frustrating! Let's stop and examine the pathophysiology of chronic constipation and encopresis. Whether due to a bad toileting experience, constipation from another cause, or perhaps an anal fissure, children who end up encopretic begin by experiencing pain with defecation. As a result, when the child feels the sensation associated with defecation that should trigger relaxation of the external anal sphincter, he or she instead, consciously or unconsciously, contracts the sphincter and thus prevents stooling with the expected pain that accompanies it. Chronically doing this results in increased amounts of stool collecting in the rectum causing it, over a period of time, to gradually dilate. As dilation occurs, the rectum also becomes less capable of contraction, resulting in more stool retention. In addition, sensory capacity diminishes, so that stool retention is even easier. This process becomes a self-fulfilling prophecy: pain, which leads to retention, which leads to more pain when stool is eventually expelled, which leads to more retention coupled with an increased capacity to retain stool. Eventually, softer stools can "leak out" around this hard stool mass without the child being aware of the process.

Before beginning therapy for functional encopresis, it is important to rule out the very small percentage of children with organic causes of constipation such as Hirschsprung's disease, sacral nerve abnormalities, or other unusual conditions. In addition, in children who show no response to therapy, consider re-evaluating them for organic causes.

Remember that the key to successful therapy is pain control. Unless and until these children experience pain-free defecation, and for a long period of time, you won't be able to break this cycle.

As you've noted, MiraLax and other pharmacologic agents are important adjuncts in therapy. MiraLax is an osmotic agent that causes water to be retained with the stool. It's a good first-line therapy as are other osmotic agents such as lactulose and bulk-producing laxatives such as Maltsupex (malt soup extract). In addition, stool softeners such as mineral oil or Colace (docusate sodium) and bulking agents such as psyllium are important. These agents, coupled with a toileting regime that includes timed toilet sits and a reward system such as star charts, may be all that is necessary in children with less significant encopresis.

For children who present with a week or more since their last stool, you may need to begin with cleansing enemas for a period of several days, followed by stimulant laxative products such as milk of magnesia or Senokot (natural vegetable laxative) in order to prevent stool reaccumulation. Doses vary and need to be titrated for an individual child and continued for a period of 2-4 weeks.

Parents must be educated in ways to manage their children's medication themselves. They'll need to adjust medications in order to allow a stool at least every 1-2 days. Medications, along with behavioral interventions, should be continued for a period of 6-12 months until the rectal vault has resumed normal size and tone. After that, parents and children must be instructed in the importance of monitoring stooling and restarting therapy should the child go more than a couple of days without a stool. Dietary changes, such as insuring adequate fiber and fluid intake, should be lifelong.

Patience is the key! It takes a child a month to develop encopresis, and it will take months to resolve.


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