gastrointestinal disorders
Irritable Bowel Syndrome (IBS)
Key Points
IBS is recurrent abdominal discomfort or pain accompanied by ≥ 2 of the following: pain is related to defecation, pain is associated with a change in frequency of stool (diarrhea or constipation), or pain is associated with a change in consistency of stool. Etiology is unclear but appears to involve both physiologic and psychosocial factors. In patients with red flag findings, such as older age, weight loss, or rectal bleeding, more dangerous disorders should be excluded. Common illnesses that may be confused with IBS include lactose intolerance, drug-induced diarrhea, post-cholecystectomy diarrhea, laxative abuse, parasitic diseases, eosinophilic gastritis or enteritis, microscopic colitis, small intestinal bacterial overgrowth, celiac disease, and early inflammatory bowel disease. Typical testing to consider includes complete blood count, biochemical profile (including liver tests), serologic markers for celiac disease and tests for inflammation (for patients with diarrhea predominance), and measurement of thyroid-stimulating hormone and calcium levels (for patients with constipation). A supportive, understanding, and therapeutic physician–patient relationship is essential; direct drug therapy toward the dominant symptoms. 