Symptom-Based Diagnosis in Pediatrics (CHOP Morning Report) 1st Ed.

CHAPTER 12. CONSTIPATION

HEIDI C. WERNER

DEFINITION OF THE COMPLAINT

Constipation, a common problem in childhood, accounts for 10%-25% of all referrals to pediatric gastroenterologists. Although constipation is usually characterized by the painful passage of hard stool, the term refers to both the consistency and frequency of stools. A precise definition of constipation is difficult since the normal stooling pattern differs among individuals and varies by age. The frequency of stools in most children decreases from a mean of four per day in the first week of life to two per day by 16 weeks of age, and one stool per day at 4 years of age.

All cases of constipation involve a failure to evacuate the lower colon completely with a bowel movement. Thus, a child who has two small stools per day may not have evacuated the colon, whereas the child who has two large stools weekly may not be constipated. The child who has experienced pain while defecating may aggressively contract the external sphincter to prevent expulsion of stool when the urge to defecate arises. This leads to the collection of increased amounts of stool in the rectum and during a period of weeks to months the rectum gradually dilates, becoming less capable of peristaltic activity.

COMPLAINT BY CAUSE AND FREQUENCY

While functional fecal retention is the most common cause of childhood constipation, several other causes must be considered in the differential diagnosis (Table 12-1).

TABLE 12-1. Differential diagnosis of constipation.

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CLARIFYING QUESTIONS

A diagnosis of constipation can readily be made by the history and physical examination. The following questions may provide clues to the diagnosis:

• What is the stool consistency, caliber, and volume?

—Small, pellet-like stools indicate incomplete evacuation. Intermittent, massive stools are characteristic of functional fecal retention.

• Did the child have a bowel movement in the first 24 hours of life?

—A normal bowel movement in the first 24 hours of life can help lower the suspicion of Hirschsprung disease.

• Were there any neonatal complications or surgery?

—Neonatal gastrointestinal complications such as necrotizing enterocolitis or prior surgery can lead to strictures or adhesions and predispose a child to constipation and small bowel obstruction.

• Is the child going through any transitions such as from breast- to bottle-feeding, diapers to toilet training, or home to childcare or school?

—Developmental and social transition periods are the most common time for the beginning of functional constipation. Asking about transitions such as a move into childcare can help identify a possible cause of constipation and also provide parents insight into the diagnosis.

• Is there a history of sexual abuse?

—The emotional trauma of sexual abuse can predispose a child to constipation.

• Is the child on any medication?

—Several medications can cause constipation (Table 12-1).

• Are there any other symptoms (e.g., fever, blood in stool)?

—Symptoms associated with constipation point to an organic cause.

• Has the family kept a journal of stooling patterns and diet?

—A 5-7 day journal of stooling patterns and diet can help both the clinician and family objectively assess the true extent of constipation. Diet history can also help identify a cause of constipation and also help as a starting point for therapy for functional constipation.