Irritable bowel syndrome: Clinical sciences
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Irritable bowel syndrome, or IBS for short, is a chronic bowel condition characterized by recurrent abdominal pain associated with abnormal bowel movements. The cause is unknown but could be related to changes in the normal gut microbiota, autonomic dysfunction, altered motility of the gastrointestinal tract, and psychological factors. Now, based on the clinical manifestations, IBS can be diarrhea-predominant, constipation-predominant, or mixed.
Generally, individuals with irritable bowel syndrome are stable, so first, you should obtain a focused history and physical examination. History findings typically include bowel habit changes for at least 6 months, which are usually related to diarrhea or constipation. Your patient will also report abdominal pain or discomfort that’s typically relieved with defecation. In some cases, the patient could report abdominal bloating, or they might have a history of depression, anxiety, fibromyalgia, trauma, or recent infectious gastroenteritis. On the physical exam, you might notice abdominal tenderness during palpation, or find hemorrhoids or anal fissures on the rectal exam.
Now, here’s a clinical pearl! Describing stools can be challenging for some patients. To make it easier, you can use a tool called the Bristol Stool Scale, which ranks stool from 1, solid lumps or balls to 7, watery diarrhea.
Now, based on these history and physical exam findings, you should suspect a chronic bowel condition. But, before you diagnose irritable bowel syndrome, first, you need to assess your patient for red flag features, which could indicate serious underlying conditions, like colorectal cancer. These include hematochezia, unintentional weight loss, a family history of colon cancer, acute onset of constipation in an older adult, change in stool caliber, anemia, and the presence of a rectal mass.
Sources
- "ACG Clinical Guideline: Management of Irritable Bowel Syndrome" American Journal of Gastroenterology (2020)
- "Medicine. 26th Edition. " Elsevier, Inc; (2019)
- "The Emerging Role of Brain-Gut Therapies for Irritable Bowel Syndrome. 14(7):436-438. Accessed August 8, 2023. https://pubmed.ncbi.nlm.nih.gov/30166961/" Gastroenterol Hepatol (N Y) (2018)