350 Ch 349. Irritable Bowel Syndrome (IBS) and Functional GI Disorders

IBS 是最常見 functional GI disorder; prevalence 10-15% globally; Rome IV criteria: recurrent abdominal pain ≥ 1 day/week × 3 months + 2+ of (related to defecation, change in stool frequency, change in stool form)；subtypes：IBS-D (diarrhea), IBS-C (constipation), IBS-M (mixed), IBS-U (unspecified)；Bristol Stool Scale 1-7 for classification；pathophysiology：multifactorial - visceral hypersensitivity + altered motility + altered microbiome + low-grade inflammation + brain-gut axis dysfunction + psychosocial；diagnosis：clinical + exclude alarms (weight loss, hematochezia, anemia, family hx, late-onset); fecal calprotectin (rule out IBD)；treatment：dietary (low FODMAP — most evidence) + medication by subtype: IBS-C (linaclotide, lubiprostone, plecanatide, tenapanor, prucalopride); IBS-D (rifaximin, eluxadoline, alosetron, loperamide); IBS general (TCA, SSRI, probiotics)；other functional GI: functional dyspepsia (Ch348), functional constipation, functional diarrhea, cyclic vomiting syndrome, cannabinoid hyperemesis syndrome；2024 emerging: microbiome modulation, FMT trials, gut-brain modulators。