Description

• Defined by DSM-5 and Rome IV diagnostic criteria as repetitive and inappropriate passage of feces
• Diagnostic criteria: chronological and developmental age of at least 4 years; repeated passage of stool in inappropriate places—floors, clothes; symptoms mostly involuntary but may be intentional; at least one event per month for 3 months; behavior can’t be explained by other medical conditions or use of substances (e.g., laxatives); excludes mechanisms involving constipation
• Categories:
  • With constipation and overflow incontinence (functional constipation or retentive encopresis)—more common
  • Without constipation (nonretentive fecal soiling or nonretentive fecal incontinence)
• Constipation is passing delayed or infrequent hard stools with pain and straining.

Epidemiology

Incidence
There is no clear difference in the incidence of functional constipation between women and men. Constipation in children accounts for 3% of primary care visits and 25% referrals to pediatric gastroenterology. Functional constipation is the cause of 95% of all constipation in children and adolescents with median age of onset ~2.3 years of age and often coinciding with transition to solid foods, toilet training, or start of school.

Prevalence
Occurs in 1–3% of children 4 years of age and 25% of children with functional constipation go on to have adult GI issues.

Etiology and Pathophysiology

• In 90% of cases, encopresis develops as a consequence of chronic constipation, with resulting overflow incontinence (retentive encopresis). The other 10% are caused by specific organic etiologies.
• Constipation causes pain with defecation which causes further stool withholding. Stool withholding increases colonic water absorption, making stools harder and more difficult to pass.
• Withholding behaviors such as hiding, rocking back and forth, or fidgeting when feeling the urge to defecate can be confused with signs of straining to defecate. Many children voluntarily withhold stool for fear of pain or a preoccupation with not interrupting social activities.
• Chronic constipation with irregular and incomplete evacuation results in progressive rectal distension and stretching of the internal/external anal sphincters.
• Chronic rectal distension causes habituation, leading to the loss of sensing the normal urge to defecate causing abdominal pain, nausea, and bloating. Eventually, soft or liquid stool leaks around the retained fecal mass.
• Psychological: stool withholding, fear, anxiety; difficulty with toilet training, including unusual anxiety or conflict with parent; resistance to using public toilet facilities, such as school bathrooms or outdoor toilets; associated with abuse; developmental delay
• Anatomic: rectal distension and desensitization, anal fissure or painful defecation; muscle hypotonia, slow intestinal motility; Hirschsprung disease, cystic fibrosis; spinal cord defects (e.g., spina bifida), congenital anorectal malformations; anal stenosis, anterior displacement of the anus, postoperative stricture of anus or rectum; pelvic mass, neurofibromatosis
• Dietary or metabolic: inadequate dietary fiber; excessive protein or milk intake; inadequate water intake; hypothyroidism; hypercalcemia; hypokalemia; diabetes insipidus; diabetes mellitus; Food allergy; gluten enteropathy
• Medication side effects

Genetics
None known; although incidence may be higher in children with family history of constipation

Risk Factors

Transition of foods: breast milk to formula or cow’s milk or start of solid foods; parental conflicts or divorce; new sibling; history of constipation; painful defecation; difficulty with bowel training, including social pressure related to early daycare placement; organic/anatomic causes; anxiety and depression; insufficient fluid or fiber intake; fear of using bathrooms/public restrooms; attention deficit; history of abuse; medications (particularly opiates, ADD/ADHD medications, antidepressants)

General Prevention

Family education: toilet training when ready; optimize fluid and fiber intake.

Commonly Associated Conditions

Constipation, developmental and behavioral diagnoses, urinary incontinence, cow’s milk protein allergy, autism and ADHD, psychosocial or neurological conditions—especially nonretentive fecal incontinence, UTI