Luciano, Kristy L. MS, PA-C
Constipation is common in children, with prevalence of about 23% in children attending primary care clinics in the US, and a worldwide prevalence of 0.7% to 29.6%.1,2 PAs who work in family practice, pediatrics, and EDs frequently encounter children who are constipated and should be aware of organic disorders that may cause constipation, how to accurately diagnose functional constipation, and current recommendations for treatment. This article reviews the diagnosis and treatment of functional constipation for children over the age of 1 year. Treatment consists of three stages: family education, disimpaction, and maintenance therapy.
Functional constipation is constipation without evidence of an organic cause.3 The Rome III criteria (Table 1) determine functional constipation by the presenting signs and symptoms, which are commonly accepted as the standard for diagnosing constipation.4 Functional constipation often begins during toilet training with an acute episode of painful passage of stool. Children begin to associate the passage of stool with pain and actively hold in stool by tightening the external anal sphincter when they sense the need to defecate. The stool then moves back into the recto-sigmoid colon. Withholding leads to a dry fecal mass in the rectum or distal colon. Passage of this large, dry stool causes further pain, which in turn leads to additional withholding behavior. The rectum enlarges to accommodate the retained fecal mass and over time the urge to defecate decreases. Fecal incontinence occurs when liquid stool leaks around the retained stool.5 Parents or caretakers may mistake fecal incontinence for diarrhea.
Children with constipation may present with abdominal pain, urinary symptoms, crying, decreased frequency of bowel movements, and stool retention.6 Children who are withholding stool may rock back and forth, stiffen their legs, or hide or squat in a corner. Parents often mistake this withholding behavior for straining. Parental concern over anorexia may be a presenting compliant in primary care clinics.
A thorough history is critical to the accurate diagnosis of constipation in children. Questions should include age of onset, whether the child had delayed passage of meconium as a neonate, stool size and consistency, urinary symptoms, withholding behaviors, vomiting, school toilet use, whether the child has a history of rectal prolapse, presence of fecal incontinence, and history of abuse or trauma.
Conduct a thorough physical examination, including an external examination of the perianal area. Examine the anorectal area for amount and consistency of stool and assess for the superficial anal reflex (anal wink), anal tone, and occult blood.5
Signs indicating an organic cause of constipation include a tuft of hair or dimpling over the sacral spine; decreased or absent lower extremity reflexes; and absence of an anal wink, which may indicate a spinal cord abnormality. Clinical suspicion for a diagnosis of Hirschsprung disease should be high in children who had delayed passage of meconium as neonates. Children with hypothyroidism may present with constipation, failure to thrive, or bradycardia. Fever, weight loss, bloody diarrhea, polyuria, polydipsia, and recurrent upper respiratory infections may indicate organic disease and require further workup. Table 2 lists conditions that should be included in the differential diagnosis for constipation in infants and children.
Laboratory and diagnostic testing usually are not indicated in constipated children unless an organic cause is suspected. However, a plain film radiograph of the abdomen may be helpful if constipation is suspected and the patient refuses anorectal examination, or in patients who are obese.3
The majority of children who present with constipation have functional constipation. These children typically present with a history of large, painful, infrequent stools and withholding behavior. Common physical examination findings include a rectal fecal mass.
Families and caregivers should understand the pathophysiology of constipation. A thorough knowledge of the cycle of pain, withholding, rectal distention, and fecal incontinence may help caregivers minimize shaming or punitive actions toward the child. Families should understand triggers such as avoiding public toilets, being too busy to use the toilet, and incomplete evacuation due to rushing. Behavioral interventions might include rewarding the child for defecation and for improved toilet habits such as sitting on the toilet for 5 to 10 minutes after breakfast and dinner to take advantage of the gastrocolic reflex. Children with fecal incontinence who are treated with laxatives and behavioral therapy, including dietary interventions, toilet training, and incentives, may have greater treatment success than children treated with laxatives alone.7
The first step in medical treatment of constipation is disimpaction of the retained fecal mass. Historically, this has been accomplished via rectal enema; however, oral medication can also be an effective disimpaction agent. A prospective randomized controlled trial by Bekkali and colleagues evaluated children ages 4 to 16 years with functional constipation and rectal impaction.8 Disimpaction was performed with rectal enemas or orally administered laxatives. The authors concluded that enemas and polyethylene glycol were equally effective in treating rectal impaction in children. Children who were treated with enemas complained of more abdominal pain but less fecal incontinence and watery stools than children treated with polyethylene glycol. Once disimpaction was achieved, the fecal incontinence with polyethylene glycol decreased.
Other oral medications such as senna (a stimulant laxative), lactulose, mineral oil, or high-dose magnesium hydroxide may be used alone or in combination to disimpact a rectal fecal mass.5
Guidelines from the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) state that disimpaction may be achieved via the rectal or oral route.5 An advantage of oral disimpaction with polyethylene glycol is the increased palatability of treatment for children and families, possibly leading to improved adherence. Rectal disimpaction works quickly; however, it is more invasive. The final choice of disimpaction agent will vary based on practitioner experience and parental inclination.
Once rectal disimpaction is achieved, the frequent passage of soft stool must be maintained. This usually requires medical therapy for many months or longer, due to high relapse rates.5 Medications used for maintenance therapy include mineral oil, magnesium hydroxide, lactulose, sorbitol, polyethylene glycol, or a combination of these agents. Stimulant laxatives typically are reserved as short-term or rescue medications in the initial treatment of constipation and are not recommended as maintenance therapy.
In addition to being an effective disimpaction agent, polyethylene glycol is effective for maintenance therapy in children and has proven to be equal or more effective than placebo or standard maintenance treatment such as lactulose.8–10 Using a single agent for the treatment of constipation is attractive to parents and may improve adherence. The final maintenance medication choice will depend on both parental and clinician experience and preferences.
Once the child has resumed regular bowel movements, maintenance therapy may be discontinued. However, relapse is common and clinicians should discuss with parents the possible need for laxatives to be reintroduced.
Children taking polyethylene glycol for maintenance therapy may benefit from increased fluid intake. Bae and colleagues evaluated the effect of increased fluid intake on children taking osmotic laxatives for constipation.10 Children on polyethylene glycol benefited from increased fluid intake, showing improved stool frequency and consistency. However, the children treated with lactulose had no benefit from increased fluid intake. This discrepancy may be explained by the chemical composition of polyethylene glycol, which can hold water via hydrogen bonding in addition to its osmotic effect. Therefore, polyethylene glycol may be able to hold more water as fluid intake is increased compared to lactulose, which has a lower saturation threshold.11 Although increased fluid intake may be beneficial in children taking polyethylene glycol, dietary changes should not be forced.
Clinicians frequently recommend that children with constipation consume more dietary fiber and drink less milk. Research on the effects of dietary fiber in constipated children is conflicting. NASPGHAN guidelines state that evidence is insufficient to support dietary fiber as maintenance medication for children with functional constipation.5 A diet consisting of whole grains, fruits, and vegetables may be helpful for children with constipation but should not be relied on exclusively for maintenance therapy.
Because constipation can be a symptom of cow's milk intolerance in children, a trial elimination of cow's milk may be considered in children with chronic constipation.12 Further research in this area is needed.
Safety is an important consideration when prescribing maintenance medication for children. Osmotic laxatives have traditionally been considered safe for use in children. Adverse reactions include abdominal discomfort, diarrhea, flatulence, bloating, and nausea.13 Serious adverse reactions are rare when osmotic laxatives are used in appropriate dosages and with adequate monitoring.13
The long-term prognosis of children with functional constipation is unclear. One study, conducted in the Netherlands, found that about 25% of children treated for functional constipation continued to be symptomatic as adults.14 Predictors of poor adult outcomes included older age at onset of constipation, low defecation frequency, and delay between onset of symptoms and evaluation in a pediatric gastroenterology clinic. Clinicians managing difficult-to-treat children with functional constipation should consider early referral to gastroenterology.14 In a small retrospective study, constipation in childhood appeared to be a predictor of irritable bowel syndrome in adulthood.15 Further research is needed to explore links between childhood and adult functional gastrointestinal disorders.
Clinicians who evaluate children with functional constipation should conduct a thorough history and physical examination, including an anorectal exam. Parents should be reassured that the constipation is not caused by an organic condition and can be managed effectively. Patient education should focus on parental understanding of the pathophysiology and triggers of functional constipation in young children. Disimpaction should be achieved via the oral or rectal route. Parents and patients may demonstrate increased compliance with oral disimpaction with polyethylene glycol; however, rectal disimpaction is quick and effective. Once disimpaction has been achieved, maintenance therapy should be initiated. Osmotic laxatives are an effective and safe choice for maintenance therapy of functional constipation in children.13 However, relapse is common and clinicians should discuss with parents the possible need for laxatives to be reintroduced if symptoms recur.5 Finally, providers should consider referral to a pediatric gastroenterologist for patients who do not respond to initial treatments, as delay between onset of symptoms and referral to a pediatric gastroenterologist may suggest a poor prognosis.14
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© 2013 American Academy of Physician Assistants.