Gastroenterology
Irritable Bowel Syndrome
과민성장증후군
Functional GI disorder of chronic abdominal pain and altered bowel habits without structural abnormality
- How common
- Adults 10–15%
- Typical age
- Ages 20–40
What is it?
Multifactorial: brain-gut axis dysfunction, visceral hypersensitivity, dysmotility, low-grade inflammation, microbiome alterations.
Commonly affected: Colon/small bowel (entire GI tract possible)
How it develops
- Brain-gut dysregulationStress/emotion modulates gut signaling
- Visceral hypersensitivityAmplified pain perception to normal stimuli
- DysmotilitySpasm/hyper- or hypomotility
- Microbiome/inflammationMicrobiome shifts, low-grade inflammation
Symptoms
- Recurrent abdominal pain≥1x/week, related to defecation
- Altered bowel habitsDiarrhea, constipation, or mixed
- BloatingWorse postprandially
- Sense of incomplete evacuationPersistent feeling after defecation
- Mucus in stoolMucus may accompany
How it is examined
- Rome IV criteriaPain ≥1d/wk for ≥3 mo, related to defecation
- Exclude alarm featuresWeight loss, blood, nocturnal symptoms, onset >40
- Largely normal examNormal except mild tenderness
Imaging
Imaging not needed for diagnosis unless alarm features.
- Normal
Colonoscopy if >50 or alarm features; rule out celiac, thyroid, CRP.
- Normal mucosa
- Microscopic colitis
Non-surgical care
- Low-FODMAP dietRestrict fermentable oligo/di/monosaccharides and polyols x 6 wk
- Soluble fiber (IBS-C)Psyllium/ispaghula soluble fiber
- AntispasmodicMebeverine, dicyclomine, peppermint oil
- IBS-C: linaclotide, lubiprostoneTargeted IBS-C agents
- IBS-D: loperamide, rifaximin, eluxadolineTargeted IBS-D agents
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
None (functional disorder)
Procedures that may be discussed
- CBT
- Low-dose TCA or SSRI
- Gut-directed hypnotherapy
Outlook
Chronic fluctuating course; >60% improve with diet + drug combination.