Irritable Bowel Syndrome



  • Irritable bowel syndrome (IBS) is a common functional GI tract disorder where defecation is disordered and associated with abdominal discomfort.
  • IBS is characterized by abdominal pain, bloating, diarrhea, or constipation
  • Symptoms of IBS do not result from inflammatory, infectious, metabolic, or anatomic causes. However, there can be overlap with other conditions.
  • Symptoms typically exacerbated by stress or particular foods (i.e., spices, fatty foods, caffeine, certain carbohydrates, etc.).


  • 10–15% of the general population is affected to some degree by IBS.
    • Prevalence estimates vary based on whether the study is community-based or practice-based.
    • Higher estimates in the community reflect the fact that many people do not seek medical care for their IBS symptoms.
    • Prevalence is also based on whether Manning, Rome II, or Rome III criteria are used.
  • More common in females
  • IBS occurs in children.
    • 6% of middle school students
    • 14% of high school students

Risk Factors

  • Prior history of bacterial enteritis
  • History of abuse or trauma


  • IBS considered a disorder of GI function relating to motility, sensation, and/or perception
  • Best model is a biopsychosocial construct with dysregulation of the gut-brain homeostasis affected bidirectionally by both peripheral and central factors.
  • The pathogenesis of IBS is believed to be multifactorial and include the following:
    • Abnormal gut motility
    • Genetics
    • Bacterial overgrowth
    • Visceral hypersensitivity
    • Behavioral response
    • Microscopic inflammation
    • Dysregulation of brain-gut axis
    • Malabsorption

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