Gut–Brain Axis

  • Definition: Bi-directional communication between the GI tract and central nervous system via neural, hormonal, and immune pathways.
  • Importance: Influences motility, sensitivity, and mood; targeted by diet, probiotics, and psychological therapies.

Irritable Bowel Syndrome (IBS)

  • Definition: Functional disorder with abdominal pain and altered bowel habits (IBS-C, IBS-D, mixed).
  • Management: Low-FODMAP diet, fiber adjustment, antispasmodics, neuromodulators, gut-directed CBT.

Functional Bowel Disorder

  • Definition: Broad category including IBS, functional diarrhea, functional constipation without structural cause.
  • Management: Symptom-directed therapy (laxatives, antidiarrheals), dietary changes, behavioral therapy.

Functional Dyspepsia

  • Definition: Epigastric discomfort without identifiable organic disease.
  • Symptoms: Early satiety, postprandial fullness, epigastric pain or burning.
  • Management: Small frequent meals, PPI or H2-blocker trial, prokinetics, low-dose antidepressants, stress management.