Stool impaction can be felt on abdominal examination in about 50% of patients at presentation. Firm packed stool in the rectum is highly predictive of fecal impaction. A rectal examination allows assessment of sphincter tone and size of the rectal vault. Evaluation of anal placement and existence of anal fissures also is helpful in considering etiology and severity. A neurologic examination, including lower extremity reflexes, anal wink, and cremasteric reflexes, may reveal underlying spinal cord abnormalities.
Abdominal x-ray is not required. It can be helpful to showto the family the degree of colonic distention and fecal impaction. In general further studies, such as barium enema andrectal biopsy, are indicated only if an organic cause for theconstipation is indicated by history or physical examination(see Chapter 129). Similarly although endocrinologic conditions such as hypothyroidism can cause chronic constipation,laboratory studies are not indicated without history or physicalexamination suggesting such a disorder.
The differential diagnosis for functional constipation and soiling includes organic causes of constipation (e.g., neurogenic, anatomic, endocrinologic, gastrointestinal, and pharmacologic). A child with chronic constipation and soiling who had delayed passage of meconium and has an empty rectum and tight sphincter may have Hirschsprung disease (see Chapter 129). Chronic constipation may be a presenting sign of spinal cord abnormalities, such as a spinal cord tumor or a tethered cord. Physical examination findings of altered lower extremity reflexes, absent anal wink, or a sacral hairy tuft or sacral sinus may be a clue to these anomalies. Hypothyroidism can present with chronic constipation and typically is accompanied by poor linear growth and bradycardia. Anal stenosis may lead to chronic constipation. The use of opiates, phenothiazine, antidepressants, and anticholinergics also may lead to chronic constipation. Developmental problems, including mental retardation and autism, may be associated with chronic constipation.
Treatment begins with education and demystification forthe child and family about chronic constipation and soiling,emphasizing the chronic nature of this condition and the goodprognosis with optimal management. Explaining the physiologic basis of constipation and soiling to the child and the family alleviates blame and enlists cooperation. Education may improve adherence to the long-term treatment plan (Table 14-1). One half to two thirds of children with functional constipation recover completely and no longer require medication.
Constipation affects 16% to 37% of children. 1% to 4% of children have functional constipation and soiling. Functional constipation with/without soiling begins early in life due to a combination of factors:
Withholding of stool to avoid discomfort
Use of medications that are constipating
When chronic impaction, physiologic changes at the rectum reduce a child’s bowel control.
Dilated rectal vault results in reduced sensation to standard fecal volume.
Rehabilitation of rectal musculature and strength requires several months.
Until then, dilated rectal musculature may be less able to expel stool effectively.
Paradoxical anal sphincter contraction may occur when the urge to defecate is felt; it can lead to incomplete emptying of stool at defecation attempt.
Many children do not recognize their soiling accidents owing to olfactory accommodation.
Low self-esteem or other behavioral concerns are common on presentation.
Improve for most with education and management for the constipation and soiling.
Effective management of functional constipation requires a substantial commitment of the child/family, usually for 6–24 mo.
Degree of child and family adherence is likely a predictor of the child’s success.
*The common features of the transition to the toddler diet (decreased fluid intake, continued high dairy intake, and finicky eating patterns) make this a high-risk time during development for constipation problems.