Irritable Bowel Syndrome

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DESCRIPTION

  • Irritable bowel syndrome (IBS) describes chronic but intermittent abdominal pain associated with changes in stool form (appearance) and/or frequency.
  • IBS subtypes are based on the predominant stool pattern
    • IBS with constipation
    • IBS with diarrhea
    • IBS with constipation and diarrhea (mixed)
    • IBS unspecified
  • Abdominal pain in IBS constipation does not remit with treatment for constipation.
  • IBS is the most common of the four pediatric functional abdominal pain disorders (more recently referred to as disorders of gut–brain interaction [DBGIs]) as defined by the pediatric Rome IV diagnostic criteria.

EPIDEMIOLOGY

  • IBS prevalence in children across the United States based on parental report using pediatric Rome III criteria is 2.8%. Worldwide prevalence is estimated to be approximately 13.8% (4.1–23%). Inconsistent methods among studies limit interpretation of this data.
  • Prevalence similar in children aged <12 years or ≥12 years
  • More common in girls
  • By parents’ report, quality of life is lower in children and adolescents with IBS than in patients with inflammatory bowel disease.

ETIOLOGY

  • The underlying etiology of IBS is multifactorial and is not fully elucidated. Potential contributors to onset and/or severity include genetic predisposition, preceding acute gastrointestinal illness, visceral hypersensitivity, psychosocial factors (e.g., child and/or parent somatization, anxiety, depression, hypervigilance), low-grade gut inflammation, and/or gut dysbiosis. Different factors lead to a variety of disease phenotypes.
  • IBS is likely the result of multiple mechanisms that differ among patients. It is considered a DGBI in which symptoms in an individual patient reflect the components of the bidirectional gut–brain axis affected and the degree to which they are involved.
  • Its pathogenesis currently is best understood via the biopsychosocial model: a multidimensional process with sensory, emotional, and cognitive contributions to symptoms that relates to peripheral amplification of visceral signals, reduced inhibition of spinal ascending pain signals, and potential amplification of pain via psychological distress.
  • Suggested underlying mechanisms include the following:
    • Genetics
    • Visceral hypersensitivity
    • Central hypersensitivity
    • Abnormal neuroimmune interactions
    • Abnormal gut immune response to food antigens
    • Gastrointestinal dysmotility
    • Gut dysbiosis
    • Psychological distress
    • Somatization

RISK FACTORS

  • Genetics (higher prevalence in monozygotic than dizygotic twins but low overall concordance)
  • Infectious enteritis/colitis
  • Inflammatory/immune-mediated disorders
  • Early life use of antibiotics
  • Early life pain or trauma (e.g., low birth weight)
  • Family stress
  • Parenting style
  • Anxiety
  • Depression
  • Somatization
  • Poor coping style
  • Dysmotility
  • Abnormalities in gut microbial population composition (dysbiosis)

GENERAL PREVENTION

No preventive measures are recognized.

COMMONLY ASSOCIATED CONDITIONS

  • Patients with IBS may, over time, have symptoms of other DGBIs (based on pediatric Rome IV criteria) such as functional dyspepsia and functional abdominal pain not otherwise specified.
  • Many children with IBS also experience extraintestinal pain symptoms such as headaches, chest pain, muscle soreness, back pain, and joint and/or extremity pain.

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