Irritable Bowel Syndrome

Irritable Bowel Syndrome is a topic covered in the 5-Minute Clinical Consult.

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  • A gastrointestinal disorder characterized by
    • Chronic and/or recurrent abdominal pain or discomfort and alteration in bowel habits
  • May be characterized as diarrhea-predominant or constipation-predominant; may alternate between
  • Synonym(s): spastic colon; irritable colon


Irritable bowel syndrome (IBS) accounts for up to 50% of visits to gastroenterologists:

  • Second only to upper respiratory infection as cause of lost workdays

Pooled estimate of 11% IBS prevalence internationally; ranges from South Asia (7%) to South America (21%) (1)

  • Predominant age: 20 to 39 years
  • If age >50 years, consider other diagnoses.
  • Predominant sex: in the United States, female > male (2:1)
  • More common in low socioeconomic communities

Etiology and Pathophysiology

  • The etiology is unknown; associated with abnormalities of intestinal motility and enhanced sensitivity to visceral stimuli
  • The trigger may be luminal or environmental.
  • Evidence for the role of small intestinal bacterial overgrowth (SIBO) in IBS and association with antibiotic therapy is controversial; older age and female gender are predictors of SIBO in IBS patients.

Unknown but more common in families of IBS patients

Risk Factors

  • Other family members with similar GI disorder
  • History of childhood sexual abuse
  • Sexual/domestic abuse (primarily in women)
  • Depression
  • Gastrointestinal infection

Pediatric Considerations
No risk to mother or fetus

General Prevention

See “Diet.”

Commonly Associated Conditions

  • Chronic migraine
  • Fibromyalgia
  • Chronic fatigue syndrome
  • Sleep disorders
  • Psychiatric disorders: major depression, anxiety, somatoform disorders, and posttraumatic stress
  • Chronic pelvic pain
  • Temporomandibular joint dysfunction

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