Chapter 76: Constipation

BACKGROUND

Constipation is a common pediatric disorder, with studies citing a prevalence up to 30% with a median of 9% of children;¹ however, in special patient populations such as children with cerebral palsy, prevalence is much higher.² It was the principal diagnosis in 52/10,000 hospital discharges for patients <18 years old with an all-study mean cost per discharge of $17,518 in 2010.³ Because normal stooling patterns vary greatly among individuals and by age, constipation is generally defined as infrequent or difficult passage of hard stool, frequently associated with pain and straining.^1,4-8 Average stooling frequencies at different ages have been defined (Table 76-1).

Constipation can occur at any age but is particularly common in toddlers and elementary school–age children. In most studies, no significant gender-specific prevalence difference has been reported.¹

The causes of constipation can be divided into anatomic, physiologic, and functional (Table 76-2). Anatomic causes of constipation include Hirschsprung disease, imperforate anus, and bowel obstruction. Physiologic causes include a number of processes that alter bowel motility, such as hypothyroidism and spinal cord defects. Functional constipation, which results from voluntary stool withholding, is the most common cause of constipation (90%–97% of cases) and is often a self-perpetuating condition that starts with an episode of pain on defecation, a battle over toilet training, or toilet phobia.^1,4,5,7,9,10 Functional constipation may progress to encopresis, which is either voluntary or involuntary fecal incontinence in a child at least 4 years of age. It can involve leakage of stool around more distal, firm fecal impaction and is thought to result from chronic constipation secondary to functional fecal retention.

Indications for hospitalization include failure of outpatient management to resolve excessive stool burden or inability to maintain adequate intake due to associated vomiting or abdominal pain.

CLINICAL PRESENTATION

Constipation does not always present with the obvious history of infrequent or hard stools. Children may have regular, even daily, bowel movements but incomplete evacuation leading to progressive stool retention. The ...