General Discussion

The term constipation has different meanings to different people. Constipation may be defined as a delay or difficulty in defecation, present for 2 or more weeks, sufficient to cause significant distress to the patient. It must be considered that there is a wide variability in normal defecation frequency in young children. As children age, the daily number of stools decreases from a mean of 2.2 in infants younger than 1 year to a mean of 1.4 in 1- to 3-year-old children. Encopresis, the involuntary leakage of feces into the undergarments, may be an indication of constipation.

Constipation frequently begins with feeding transitions, such as the change from breast milk to formula, or from strained foods to table foods. The transition to a daycare setting or an all-day school may also be a contributing factor to constipation. The passage of a hard or large stool may cause a painful anal fissure, which may create a fear of painful defecation. This may result in a cycle of avoiding bowel movements and progress to stool retention. As the child avoids defecating, the rectum eventually stretches to accommodate the retained fecal mass, and the propulsive power of the rectum is diminished.

In children younger than one year of age, the possibility of Hirschsprung disease must be considered. Approximately 40% of children with functional constipation develop symptoms during the first year of life. Functional constipation is the diagnosis in more than 95% of cases of constipation in children older than 1 year. The passage of infrequent, large-caliber stools is highly suggestive of functional constipation. The Rome III criteria for functional constipation are outlined below. Note that the criteria are different depending whether the child is older or younger than 4 years of age (Table 11-1).

Table 11-1 Rome III Criteria for Functional Constipation

For infants up to 4 years of age, at least 2 of the following criteria must be present for 1 month: 1. Two or fewer defecations per week 2. At least 1 episode per week of incontinence after the acquisition of toileting skills 3. History of excessive stool retention 4. History of painful or hard bowel movements 5. Presence of a large fecal mass in the rectum 6. History of large-diameter stools that may obstruct the toilet

For a child with a developmental age of at least 4 years, 2 or more of the following criteria must be present at least once per week for at least 2 months with insufficient criteria for the diagnosis of irritable bowel syndrome (IBS):

Although the differential diagnosis of constipation is extensive, the diagnosis frequently can be made on the basis of a history and physical examination. A 1-week symptom and diet history may be helpful in determining the cause of childhood constipation. Red flag signs and symptoms include the following:

In the absence of red flag symptoms, no testing or subspecialist consultation is needed before treatment is initiated.

Medications Associated with Constipation

Causes of Constipation

Key Historical Features

Key Physical Findings

Suggested Work-up

Fecal occult blood testing	Recommended in all infants with constipation and in children of any age who have abdominal pain, failure to thrive, intermittent diarrhea, or a family history of colon cancer or colon polyps
Plain-film radiography of the abdomen	May be helpful to assess the presence of a fecal mass in a child who is not cooperative with abdominal or rectal examination

Additional Work-up

Thyroid function tests	If thyroid dysfunction is suspected
Serum electrolytes, calcium,and magnesium	If a metabolic disorder is suspected
Lead level	If lead toxicity is suspected
Barium enema	To evaluate for anatomic abnormalities, Hirschsprung disease or colonic strictures
Anorectal manometry	To evaluate the rectoanal inhibitory reflex and to evaluate for Hirschsprung disease
Suction rectal biopsy	To establish a tissue diagnosis of Hirschsprung disease
Magnetic resonance imaging (MRI) of the lumbosacral spine	If a spinal problem such as tethered cord, sacral agenesis, or tumor is suspected
Endomesial and tissue transglufaminase antibodies	If celiac disease is suspected on the basis of symptoms developing after wheat is introduced into the diet
Transit study	May be considered in a child with infrequent bowel movements and no signs of constipation to evaluate transit time