Original Articles: Gastroenterology
What Is Known
- Children present to pediatric gastroenterologists with functional constipation throughout childhood.
What Is New
- Children with later onset are referred to a specialist sooner than younger children.
- Children with later onset are more likely to have behavioral/developmental comorbidity.
- On an average, 2.7 years pass between the onset of functional constipation and a referral to a specialist.
Functional constipation is a common problem in pediatric gastroenterology clinics, in 1 study accounting for 21% of new patient visits (1). Functional constipation is diagnosed by symptom-based Rome criteria. Children 6 months to 4 years of age must have 1 month of ≥2 of the following features: ≤2 defecations per week, excessive stool retention, painful or hard bowel movements, large diameter stools, and a large fecal mass in the rectum. In toilet-trained children, there are additional criteria: ≥1 episode/wk of incontinence after the acquisition of toileting skills and a history of large diameter stools, which may obstruct the toilet (2,3).
The goal of this study was to describe the age of onset of functional constipation. Secondary goals were to determine the symptom duration before referral to a specialist and the frequency of behavioral or developmental abnormalities in different age groups of children with functional constipation.
This study was a retrospective review of patients seen January 2012 through 2014, approved by the Louisiana State University Health Sciences Center Human Subjects Committee and the Children's Hospital administrative review committee. From all new patients in gastroenterology clinic, we screened those with an International Classification of Diseases, Ninth Revision diagnosis code of “constipation” (564.0). We reviewed charts for a history of <2 defecations per week, ≥1 episode of incontinence per week after the acquisition of toileting skills, a history of excessive stool retention, a history of painful or hard bowel movements, presence of a large fecal mass in the rectum, and a history of large-diameter stools that may obstruct the toilet. Subjects with ≥2 of these features fulfilled the criteria for functional constipation. We recorded sex, race, age at presentation, age at onset, and other medical or mental health diagnoses. Age of onset was the age reported by the patient or parent as recorded by the clinician in the chart. We excluded patients with hypothyroidism, a history of premature birth, cerebral palsy, seizure disorder, Hirschsprung disease, or a history of anal or colorectal surgery.
We reviewed each chart criteria for infant dyschezia. These criteria were derived from the Rome III criteria for diagnosis of infant dyschezia (2). We documented comorbid behavioral and developmental problems: Attention Deficit/Hyperactivity Disorder, behavioral disorder not otherwise specified, autism spectrum disorder, and developmental delay not otherwise specified.
Because the initial analysis demonstrated that the age of onset was skewed to younger ages, we divided the subjects into 4 quartiles (Q1–Q4), with each quartile containing 25% of the study population from the youngest age of onset to the oldest. We compared these 4 groups for differences in symptom duration before presentation and frequency of medical or mental health diagnoses.
We used 1-way analysis of variance and Spearman rank correlation (rs) to determine differences in the duration of symptoms between groups. The χ2 tests were used to compare the percentage of subjects with behavioral or developmental problems among groups. A priori power analysis was conducted (power = 0.80, α = 0.05), yielding a minimum total sample size of 180 for the analysis of variance to detect a medium effect.
We identified 983 children with a constipation diagnosis code at their initial visit. We excluded 240 patients because of insufficient documentation for a functional constipation diagnosis (ie, the clinic record did not characterize the constipation in terms of the Rome III criteria for functional constipation). An additional 173 patients were excluded because they met 1 or no criteria for functional constipation. Thirty-one patients were excluded because of a history of colorectal/anal surgery or comorbid medical problems. One child met the criteria for infant dyschezia. The remaining 538 patients were included.
Table 1 describes the demographic characteristics, age of presentation, age of onset, duration of symptoms, and behavioral or developmental comorbidities of our sample. Boys made up 48.5% of our sample. The racial distribution of subjects is similar to the New Orleans metro area demographic makeup of children <18 years (4), with whites accounting for about half and African Americans accounting for about one third of the patients. Age of onset and presentation were skewed to younger ages, meaning the sample did not fit a normal distribution. Because the sample was skewed, we used median rather than mean to describe the sample and divided the sample into quartiles containing equal numbers of children (Q1–Q4) for analysis. We used medians to describe the duration of symptoms and age of presentation within each quartile. The median age of onset was 2.3 years (mean 3.3 years), with the 25th percentile having onset occur at 0.8 years and the 75th percentile at 4.8 years. The youngest group or Q1 (n = 127) had a functional constipation symptom onset age from 1 to 9 months, Q2 (n = 141) had a functional constipation onset age from 9 months to 2 years 4 months, Q3 (n = 135) ranged from 2 years 4 months to 4 years 9 months, and Q4 (n = 135) contained ages >4 years 9 months. The ages of onset and presentation to a Gastroenterology specialist are shown in Figure 1.
There were differences between groups in symptom duration, defined as (M), with Q4 (M = 1.8 ± 1.8 years) having a shorter duration of symptoms than Q3 (M = 2.7 ± 2.7 years, P = 0.039), Q2 (M = 3.0 ± 3.4 years, P = 0.001), and Q1 (M = 3.2 ± 3.1 years, P < 0.001). This effect was most evident in white children (P < 0.001) as they made up the bulk of the sample.
The oldest group had the highest frequency of mental health disorders of all the groups (χ2 = 19.487, P < 0.001 compared with all other groups). For Q4, 22% (n = 30) had a comorbid behavioral disorder diagnosis. In the younger groups, 7% (n = 9) in Q1, 4% (n = 5) in Q2, and 10% (n = 14) in Q3 had a mental health diagnosis.
There are long delays, measured in years, between the age of onset and referral to a gastroenterologist. In the time between onset and referral, functional constipation is often managed incorrectly (5). There is a need for programs for primary care clinicians to educate them on recognizing and treating functional constipation according to published guidelines (6).
Functional constipation is triggered by a painful, frightening, or otherwise negative defecation event, which changes the behavior of an infant, toddler, or school-aged child to avoid defecation (7–9). Functional constipation has been described in young children (younger than age 5) but is also reported in older children (10). Developmental delay and other mental health problems may be associated with prolonged duration of functional constipation and may contribute to late diagnosis (11,12).
In this study, we assessed the age of onset of functional constipation and the prevalence of comorbid behavioral or developmental problems in children with functional constipation. Our data show that the average age of onset of functional constipation is between 2 and 3 years, and that the majority of children have onset before school age. This data is consistent with prior studies on age of onset of functional constipation (13).
A subset of children appears to develop functional constipation at school age or later. There may be explanations for the late onset of functional constipation: development delays may decrease insight into a painful defecation experience and heighten anxiety and pain, so children with developmental delay or other mental health disorders may be more prone to form stool withholding habits than children with normal development (14); learning problems such as Attention Deficit/Hyperactivity Disorder may interfere with the ability of the child to follow through on steps to appropriate toileting behavior (15); the child may be a victim of child abuse, and encopresis is a victim's attempt to make himself/herself unattractive to the perpetrator (16); adolescents may have adult functional constipation, defined by large, painful stools and infrequent stools, and meet criteria for both disorders without withholding behaviors (17).
Our data showed that children with late onset functional constipation see a Gastroenterology specialist sooner than children with an earlier age of onset. We speculate that the earlier referral is because fecal incontinence in a school-age child is intolerable to parents and schools, and the parents seek care sooner. Children who develop functional constipation before toilet training do not suffer the social stigma that accompanies fecal incontinence, and so parents may be more comfortable caring for these children without expert advice. Our data show that, whereas the peak of onset of functional constipation is at age 2, the number of children presenting to a Gastroenterology specialist for functional constipation is similar from ages 1 through 7, indicating a delay in presentation in young children. Previous study has shown that more children 4 years and older present with functional constipation than children <4 years (1); in our sample 57% of children with functional constipation had presentation at age ≥4 years.
As a chart review, this study is subject to selection bias. We excluded 240 subjects because of insufficient clinical documentation of criteria for functional constipation; some of these children may have met the criteria and their inclusion may have altered our findings. Within our sample, only white children were statistically more likely to have a shorter duration of symptoms as age increased because of limited numbers of other ethnic groups; a larger sampling of other ethnicities may reveal similar trends in duration of symptoms. There is also concern that the number of children with behavioral or developmental problems reflects that younger children are less likely to carry a diagnosis of autism or Attention Deficit/Hyperactivity Disorder than an older child. The percentage of children with behavioral or developmental problems, however, exceeds the expected prevalence in the community, indicating a potential relation (18,19).
This study highlights the length of time children with constipation and their families suffer with symptoms before seeking care. Prolonged duration of symptoms may lead to decreased quality of life and exposure to potentially noxious medical testing and intervention (10). Encouraging clinicians and parents to think of constipation as a chronic problem with physical and mental health implications may improve outcomes and quality of life for affected children. Community outreach from gastroenterologists to primary caregivers focused on recognizing symptoms of functional constipation, reducing painful tests or therapies, and implementing North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines for the treatment of functional constipation would help decrease suffering and hasten resolution of symptoms in affected children.
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Keywords:© 2016 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology,
age of onset; age of presentation; developmental disorder; functional constipation