Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by abdominal pain and altered bowel habits without structural disease. It affects roughly 10% of adults worldwide.

Quick Facts

  • ICD-10: K58
  • Type: Functional GI disorder
  • Subtypes: IBS-D, IBS-C, IBS-M

Symptoms

  • Recurrent abdominal pain, often relieved by defecation
  • Diarrhea, constipation, or alternating between the two
  • Bloating and gas
  • Mucus in stool
  • Sensation of incomplete evacuation

By definition, IBS is diagnosed when alarm features (weight loss, bleeding, anemia, family history of colorectal cancer) have been ruled out.

Common Triggers

  • Certain foods (FODMAPs, caffeine, alcohol, spicy foods, fatty foods)
  • Stress
  • Hormonal changes (especially around menstruation)
  • Recent gastrointestinal infection (post-infectious IBS)

Treatment

  • Dietary modifications (low-FODMAP diet often very effective)
  • Soluble fiber supplements
  • Antispasmodics for cramping
  • Antidiarrheals (loperamide) or laxatives depending on subtype
  • Low-dose tricyclic antidepressants or SSRIs for pain modulation
  • Rifaximin for IBS-D
  • Cognitive behavioral therapy and gut-directed hypnotherapy
  • Probiotics (variable evidence)
  • Stress management

When to See a Doctor

See a doctor for new symptoms after age 50, blood in stool, unintended weight loss, nighttime symptoms that wake you, or family history of colorectal cancer — these require evaluation to rule out other diseases.

Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you are experiencing a medical emergency, call your local emergency number immediately.

References

  • American College of Gastroenterology. IBS Clinical Practice Guideline.