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The pathophysiology of irritable bowel syndrome involves several interconnected mechanisms.
Altered gastrointestinal motility varies by IBS subtype. In IBS with diarrhea, rapid colonic transit results in loose stools, while IBS with constipation features delayed transit, causing straining and hard stools. IBS with mixed alternates between diarrhea and constipation, leading to urgency, bloating, and a feeling of incomplete evacuation.
Dysregulation of the gut-brain axis, the two-way communication system linking the brain and digestive tract through neural, hormonal, and immune pathways, contributes to the disease.
Dysbiosis, or an imbalance in gut microbiota, develops when harmful bacteria outnumber beneficial ones, triggering immune pathways, increasing gas production, and disrupting bowel rhythms.
Visceral hypersensitivity in IBS causes exaggerated responses to normal gut stimuli due to abnormal sensory processing in the peripheral and central nervous systems.
Increased intestinal permeability allows bacteria and toxins to cross the gut barrier, triggering inflammation.
Definition
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by recurrent combinations of abdominal pain, bloating…
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