Catherine Chao, MD
Inova Fairfax Hospital for Children
Chronic constipation represents a common and distressing complaint in childhood. Peak incidence occurs between 2 and 4 years of age, and accounts for at least 3% of pediatrician visits and 25% of pediatric gastroenterologist visits. Disorders include infant dyschezia, functional constipation and functional fecal retention. Encopresis – defined as involuntary bowel movements in inappropriate places at least once a month for three months in children 4 years or older – is a consequence of functional fecal retention.
Functional fecal retention
In this condition, the child avoids defecation by purposefully contracting the pelvic floor and moving stool upward out of the anal canal. When a child repeatedly responds to the defecatory urge by withholding, the colon stretches and fills with large amounts of stool. Passing a large stool then becomes a painful experience for the child, who naturally avoids going to the bathroom. Soiling (encopresis) occurs when loose stool arrives in the rectum and seeps into the child’s underwear. This can happen in children up to 16 years of age. The usual history is passing large-diameter stools less than two times per week. The child usually assumes a “retentive posturing.”
Management of functional fecal retention
Despite intensive therapy, 30-50% of patients with functional constipation continue to have severe symptoms even after five years of follow-up. Successful treatment requires a family that is well organized and patient enough to endure gradual improvements and relapses. Close follow-up by telephone and regular office visits are essential. The general approach includes family education, initial colon “cleanout” and maintenance therapy.
STEP 1: Education and demystification help the family understand the pathogenesis of constipation./p>
STEP 2: Initial colon cleanout is achieved with high doses and combinations of polyethylene glycol, magnesium citrate, senna and saline/mineral oil enemas. The regimen usually takes three days. There is insufficient evidence to strongly support one method over another. Enemas provide only partial cleanout since they work on the bottom part of the colon and cannot get at the stool farther up. They are also invasive, emotionally draining and difficult for families to administer. The choice of treatment is best determined after discussing the options with the family and child.
STEP 3: Maintenance therapy focuses on the prevention of stool accumulation recurrence and lasts several months. This treatment includes dietary intervention, behavioral modification and laxatives to assure that stools occur at normal intervals with good evacuation. Encourage a balanced diet with whole grains, fruits, vegetables and adequate liquid. Behavior modification emphasizes regular toilet habits. Unhurried time on the toilet after meals, a sticker calendar to record bowel habits and a reward system for motivation are recommended. It is often necessary to give laxatives/stool softeners to assure that painless bowel movements occur daily. Mineral oil, magnesium hydroxide, lactulose and polyethelene glycol are recommended. Because each seems to be equally efficacious, the choice is based on cost, the child’s preference, ease of administration and the practitioner’s experience. Sometimes the child will be able to withhold stool despite high doses of lubricant laxatives and will require “rescue” therapy with a stimulant laxative, such as senna, to prevent recurrence of fecal impaction. Prolonged use of senna as maintenance therapy should be used only under the close guidance of a pediatric gastroenterologist.
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