Gastrointestinal - Irritable Bowel Syndrome Midterm Notes PDF

5 1 GASTROINTESTINAL – Irritable Bowel Syndrome Irritable Bowel Syndrome (IBS) is a chronic gastrointes.nal disorder classified as a disorder of gut-brain interac8on. It is characterized by recurrent abdo...

5 1 GASTROINTESTINAL – Irritable Bowel Syndrome Irritable Bowel Syndrome (IBS) is a chronic gastrointes.nal disorder classified as a disorder of gut-brain interac8on. It is characterized by recurrent abdominal pain and changes in bowel habits, such as diarrhea, cons.pa.on, or both. 1. Most Likely Cause Cause: o The exact cause of IBS is not well understood, but mul.ple contribu.ng factors have been iden.fied. These include: § Altered gut microbiota: Imbalances in intes.nal microbial popula.ons may contribute to symptoms. § Altera8ons in the brain-gut axis: Disrup.ons in the communica.on between the central nervous system (CNS) and enteric nervous system (ENS) may affect gut mo.lity and sensi.vity. § Dietary factors: Certain foods, such as fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs), may trigger symptoms. § Medica8on use: Certain medica.ons, including an.bio.cs, can alter gut microbiota and contribute to symptoms. § Low-grade gut inflamma8on: Chronic, low-grade inflamma.on of the gut lining has been implicated in the development of IBS. 2. Pathophysiology The pathophysiology of IBS is mul.factorial and involves a combina.on of altered mo.lity, visceral hypersensi.vity, and changes in gut microbiota and brain-gut communica.on. 1. Visceral Hypersensi8vity: o Pa.ents with IBS have heightened sensi.vity to normal gut s.muli (e.g., stretching of the intes.nes during diges.on). o Stretch receptors in the gut send exaggerated pain signals to the brain, leading to abdominal pain and discomfort. 2. Altered Mo8lity: o IBS may cause increased or decreased intes8nal mo8lity, leading to diarrhea (IBS-D), cons.pa.on (IBS-C), or a combina.on of both (IBS-M). o Abnormal contrac.ons of the intes.nes may lead to changes in bowel habits. 3. Altered Microbiota: o Dysbiosis (imbalance of gut bacteria) may cause changes in gut mo.lity, produc.on of gas, and immune response. 4. Brain-Gut Axis Dysfunc8on: o The brain-gut axis is the communica.on network between the brain and the enteric nervous system. o Dysregula.on of this axis can affect gut mo.lity, secre.on, and percep.on of pain. 3. Disease Transmission  2 Transmission: o IBS is a non-infec8ous disease and is not transmissible between individuals. o While certain gastrointes.nal infec.ons (like gastroenteri.s) can trigger the development of IBS, this process is not considered "transmission" but rather a post-infec.ous phenomenon. 4. Risk Factors Several factors can increase the risk of developing IBS. These risk factors are classified as modifiable and non-modifiable. Modifiable Risk Factors Dietary Factors: Certain foods, such as high-FODMAP foods (fermentable carbohydrates), are known to trigger symptoms. Medica8on Use: An.bio.cs and other medica.ons that alter gut microbiota can increase the risk of IBS. Stress and Anxiety: Psychological stress can disrupt the brain-gut axis and alter gut mo.lity【113:0†source】. History of Gastrointes8nal Infec8on: A gastrointes.nal infec.on (like gastroenteri8s) can result in post-infec8ous IBS (PI-IBS). Lifestyle Factors: Sedentary behavior and poor sleep hygiene have been associated with the development of IBS symptoms. Non-Modifiable Risk Factors Age: IBS is more likely to be diagnosed in younger adults than in older adults. Sex: Women are more likely to develop IBS compared to men. Gene8cs: Family history of IBS or other func.onal gastrointes.nal disorders may increase the likelihood of developing IBS. Early Life Stressors: Exposure to adverse childhood experiences (ACEs) may increase the risk of developing IBS later in life. Summary Table Criteria Irritable Bowel Syndrome (IBS) Most Likely Mul.factorial: altered gut microbiota, brain-gut axis disrup.on, low-grade Cause gut inflamma.on, diet, medica.on use. 1. Visceral hypersensi8vity: Exaggerated pain response to normal gut s.muli. 2. Altered mo8lity: Irregular contrac.ons of intes.nes. 3. Altered gut Pathophysiology microbiota: Imbalance in gut bacteria. 4. Brain-gut axis dysfunc8on: Dysregula.on of brain-enteric nervous system communica.on. Not transmissible, but prior gastroenteri8s can increase risk (post-infec.ous Transmission IBS). Modifiable: Diet (FODMAPs), an.bio.cs, stress, history of gastroenteri.s, Risk Factors sedentary lifestyle. Non-Modifiable: Age (young adults), sex (female), gene.cs, early life stressors.