1 / 10

Irritable Bowel Syndrome

Irritable Bowel Syndrome. Irritable Bowel Syndrome. A functional bowel disorder characterized by abdominal pain or discomfort and altered bowel habits in the absence of detectable structural abnormalities. . Pathophysiology of IBS. Poorly understood Proposed factors include:

phoebe
Télécharger la présentation

Irritable Bowel Syndrome

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Irritable Bowel Syndrome

  2. Irritable Bowel Syndrome • A functional bowel disorder characterized by abdominal pain or discomfort and altered bowel habits in the absence of detectable structural abnormalities.

  3. Pathophysiology of IBS • Poorly understood • Proposed factors include: • Abnormal gut motor and sensory activity • Central neural dysfunction • Psychologic disturbances • Stress • Luminal factors

  4. Pathophysiology of IBS • Abnormal gut motor activity • Colonic motor abnormalites are more prominent under stimulated conditions • IBS patients may exhibit increased rectosigmoid motor activity for up to 3 hours after eating. • The motility index of high-amplitude propagating contractions in diarrhea-prone IBS patients were greatly increased compared to healthy subjects.

  5. Pathophysiology of IBS • Abnormal Gut Sensitivity • IBS patients frequently exhibit exaggerated sensory responses to visceral stimulation. • Postprandial pain has been temporally related to entry of the food bolus into the cecum of 74 % of patients. • IBS px’s have an increased area of referred pain. This is suggestive of postprandial symptoms occuring due to a nutrient-dependent exaggerated sensory component of the gastrocolonic response.

  6. Pathophysiology of IBS • Proposed mechanisms for gut hypersensitivity: • Increased end-organ sensitivity with recruitment of “silent” nociceptors • Spinal hyperxicitability with activation of nitric oxide and possibly other neurotransmitters • Endogenous modulation of caudadnociceptive transmission • Possible development of long term hyperalgesia due to development of neuroplasticity, resulting in permanent or semi permanent changes in neural response to visceral stimulation.

  7. Pathophysiology of IBS • CNS Factors • The association of emotional disorders and stress with IBS symptom exacerbation and therapeutic response to cerebral cortical therapy. • Mid-cingulategyrus shows greater activation on MRI in IBS patients • IBS patients show preferential activation on of the prefrontal lobe, which contains a vigilance network concerned with alertness

  8. Pathophysiology of IBS • PsychologicDisturbances • Abnormal psychiatric features are recorded in up to 80 % of IBS patients. • No single psychiatric diagnosis predominates. • Prior sexual and physical abuse has also shown a link with the development of IBS. • Psychological factors influence pain thresholds as stress alters sensory threshold.

  9. Pathophysiology of IBS • IBS and infection • 544 patient study with confirmed bactierial gastroenteritis • 1/4 of the patients had subsequent IBS • Microbes involved: Campylobacter, Salmonella, and Shigella • Patients w/ campylobacter infxn who are toxin positive are more like to develop IBS

  10. Pathophysiology of IBS • Serotonin and IBS • A link between the postprandial symptoms of IBS patients and serotonin • Serotonin containing enterochromaffin cells in the colon are increased in a subset of IBS-D patients. • Plasma 5-HT levels were significantly higher in this group then the control groups.

More Related