Familial and Lifetime Associations of Childhood Functional Abdominal Pain

Professor of Psychiatry, Chief of Child and Adolescent Psychiatry, Medical Director of Pediatric Behavioral Health Services, Columbus Children’s Hospital, Ohio State University

Introduction

Recurrent abdominal pain (RAP) is best understood as a symptom rather than a diagnosis. Pediatricians have historically recognized RAP as a syndrome characterized by at least 3 episodes of abdominal pain associated with functional impairment over a period of at least three months. RAP has a median prevalence of 8.4% (range 0.3%–19%), and accounts for 2%–4% of pediatric visits; 8% of adolescents in one study reported a medical visit for abdominal pain that year. Prevalence increases into adolescence, peaking between ages 4 and 6 years and early adolescence, with an equal gender ratio in early childhood and greater female symptom reporting in adolescence. RAP has been associated with lower socioeconomic status and single parent households.

The overwhelming majority of youth with RAP do not suffer from explanatory physical disease (eg, peptic ulcer, inflammatory bowel disease), with tissue pathology in <10%. Specific structural, infectious, inflammatory, or biochemical abnormalities are particularly unusual in the absence of “red flags” such as weight loss, gastrointestinal bleeding, fever, anemia, persistent vomiting, or frequent nighttime awakening from pain. Gastroenterologists have developed a descriptive nosology for functional gastrointestinal disorders by classifying gastrointestinal symptoms in the absence of explanatory structural or biochemical abnormalities. RAP in the absence of explanatory physical disease is thus broadly considered to be functional abdominal pain (FAP).

Symptom-based diagnostic criteria for pediatric functional gastrointestinal disorders were first published in 1999. The most common diagnoses applied to youth with FAP are irritable bowel syndrome (IBS) and functional dyspepsia (FD). Approximately 25% of youth with FAP cannot be classified using existing diagnostic criteria. Lack of a biomedical explanation led early workers to consider FAP “psychogenic,” with a biopsychosocial view being emphasized more recently.

Pediatric FAP is associated with impairment (eg, poor school attendance and performance), perceived health limitations, and psychosocial difficulties. Compared to unaffected peers, youth with FAP use more ambulatory health services and are at heightened risk to undergo potentially dangerous medical investigations and procedures, with one study reporting a history of appendectomy in 11% of young adults with a childhood history of FAP. Pediatric FAP is commonly temporally associated with nongastrointestinal somatic symptoms, most notably headache, including migraine, and youth with FAP may be especially sensitive to both visceral and peripheral physical sensations.

Anxiety and depressive symptoms have also been consistently associated with pediatric FAP in tertiary care, primary care, and community-based settings with few negative reports, and anxiety may correlate with abdominal pain severity, frequency, and duration. Anxiety disorders and depressive disorders have been reported in ~75% and 40% of youth with FAP, respectively.

Developmental Implications

Though FAP may persist for years, its longitudinal course has not been well studied. Adult IBS patients are more likely to retrospectively endorse childhood FAP than controls, and early, methodologically weak follow-up studies report FAP persistence into adulthood in one-third to one-half of affected children. More recent studies of clinical samples using standardized assessments and control groups suggest that childhood FAP predicts persistent abdominal pain, IBS, other somatic symptoms, and greater health service use in adulthood. Females with childhood FAP may be significantly more likely to develop IBS and emotional distress 5 years later. A small study comparing 28 young adults with a history of FAP to 28 age- and gender-matched controls with nongastrointestinal childhood illness found that 39% of the FAP group met criteria for IBS in adulthood compared to 21% of controls, but the difference was not statistically significant. Over one-third of FAP subjects met lifetime criteria for migraine, twice as many as controls (36% vs. 14%), with a trend toward statistical significance. Former FAP subjects also endorsed significantly more physical role impairment, perceived vulnerability to physical symptoms, and hypochondriacal preoccupations than did controls.

Familial Associations

With few exceptions, parents of youth with FAP in clinical and community samples report an excess of gastrointestinal pain than do parents of controls. One study reported that 46% of children with FAP had a first degree relative with a history of chronic abdominal pain in comparison to 8% of unaffected children. Parents of youth with FAP also report more non-gastrointestinal somatic symptoms such as headache and disorders such as migraine and functional somatic syndromes such as chronic fatigue. A more recent study that compared 59 mothers of youth with FAP identified by screening in primary care to 76 mothers of pain-free controls found that 29% of FAP mothers met lifetime diagnostic criteria using a standardized assessment for IBS, with <10% of control mothers suffering from IBS. FAP mothers were also significantly more likely to suffer from migraine (37% vs. 20%), chronic fatigue syndrome (9% vs. 1%), and somatoform disorders (18% vs. 1%) than control mothers, use more ambulatory medical services, and report more somatic symptoms and bodily pain than controls. These rates are higher than reported population prevalences of 3%–20% for IBS, 10%–12% for migraine (15%–25% for women), and 0.007–%2.8% for chronic fatigue syndrome. Despite the large differences between FAP mothers and controls on univariate analyses, maternal IBS and migraine were not significantly associated with pediatric FAP on multivariable regression that adjusted for demographic correlates and maternal anxiety and depression.

Conclusion

The preceding information challenges a narrow conceptualization of FAP as a gastrointestinal disorder only. FAP is associated across development with a variety of emotional (ie, anxiety and depression) and nongastrointestinal somatic symptoms and disorders (eg, headache, migraine, fatigue), and several studies suggest childhood FAP is a better predictor of adult anxiety and depression than of IBS. Similarly, family members of FAP youth experience higher rates of somatic and emotional distress and disorders than the relatives of unaffected peers, and FAP is more consistently associated with anxiety and depressive disorders in the relatives of youth with FAP than in those with IBS or other specific somatic disorders such as migraine. These findings are consistent with a family study of adult IBS patients that found that their first degree relatives were more likely to suffer from anxiety and depressive disorders, but no more likely to suffer from IBS than those of cholescystectomy patients.

Disclosure: Dr. Campo reports no affiliation with or financial interest in any organization that may pose a conflict of interest.