Irritable Bowel Syndrome

IBS or spastic colon is the most frequent functional disorder of the GI tract. It is viewed as a biopsychosocial disorder characterized by altered GI motility, GI hypersensitivity, and psychosocial factors (anxiety, depression, stress).26,27 Other factors that may be involved include neurotransmitters such as serotonin, which may stimulate intestinal secretion and peristalsis and visceral pain receptors via 5‑HT3‑ and 5‑HT5‑serotonergic pathways.26,27

Patients with IBS experience an exaggerated gastrocolic reflex, altered gastric emptying, and increased small bowel contractions, all of which are exacerbated by food intake and/or stress.26,27 Abdominal pain relieved by defecation and pain associated with looser or more frequent stools are the hallmark of IBS. Patients may experience bloating, flocculence, dyspepsia, atypical chest pain; and diarrhea or constipation, or alternating diarrhea and constipation.26,27

Many patients find it helpful to increase dietary fiber, drink plenty of water, avoid carbonated drinks, and eat smaller meals.26,27 To relieve pain, dicyclomine, a potent anticholinergic agent that relieves smooth muscle spasm of the GI tract may be helpful.2,3,26,27 Diarrhea-predominated IBS may respond to loperamide, which binds to opiate receptor in the gut wall, inhibits the release of acetylcholine and prostaglandins, reduces peristalsis, and increases intestinal transit time.26,27