Evidence-based clinical practice guidelines for irritable bowel syndrome 2020

Abstract

Managing irritable bowel syndrome (IBS) has attracted international attention because single-agent therapy rarely relieves bothersome symptoms for all patients. The Japanese Society of Gastroenterology (JSGE) published the first edition of evidence-based clinical practice guidelines for IBS in 2015. Much more evidence has accumulated since then, and new pharmacological agents and non-pharmacological methods have been developed. Here, we report the second edition of the JSGE-IBS guidelines comprising 41 questions including 12 background questions on epidemiology, pathophysiology, and diagnostic criteria, 26 clinical questions on diagnosis and treatment, and 3 questions on future research. For each question, statements with or without recommendations and/or evidence level are given and updated diagnostic and therapeutic algorithms are provided based on new evidence. Algorithms for diagnosis are requisite for patients with chronic abdominal pain or associated symptoms and/or abnormal bowel movement. Colonoscopy is indicated for patients with one or more alarm symptoms/signs, risk factors, and/or abnormal routine examination results. The diagnosis is based on the Rome IV criteria. Step 1 therapy consists of diet therapy, behavioral modification, and gut-targeted pharmacotherapy for 4 weeks. For non-responders, management proceeds to step 2 therapy, which includes a combination of different mechanistic gut-targeted agents and/or psychopharmacological agents and basic psychotherapy for 4 weeks. Step 3 therapy is for non-responders to step 2 and comprises a combination of gut-targeted pharmacotherapy, psychopharmacological treatments, and/or specific psychotherapy. These updated JSGE-IBS guidelines present best practice strategies for IBS patients in Japan and we believe these core strategies can be useful for IBS diagnosis and treatment globally.

Keywords: 5-HT3 antagonists; 5-HT4 agonists; Antibiotics; Antidepressant; Brain-gut interactions; Complications; Diagnosis; Epidemiology; Functional bowel disorder (FBD); Functional gastrointestinal disorders (FGIDs); Infection; Inflammation; Intestinal secretagogues (gut epithelial modifier); Irritable bowel syndrome (IBS); Microbiota; Mucosal permeability; Pathophysiology; Probiotics; Prognosis; Psychosocial stress; Psychotherapy; Rome IV criteria; Treatment.

Fig. 1

Diagnostic Algorithm for IBS. Check whether the answer is positive (yes) or negative (no) at the diamond. Alarm symptoms: bloody stool, unexpected weight loss more than 3 kg within 6 months, fever, and arthralgia. Alarm signs: palpable abdominal mass, abdominal fluctuation, palpable mass, or blood on the examining gloved finger on digital rectal examination. Risk factors: age over 50 years, past or family history of organic diseases of the colorectum, and patient’s requirement for colonic examination. Routine examinations: blood chemistry analyses including plasma glucose and thyroid-stimulating hormone, complete blood count, an inflammatory reaction such as (high-sensitive) C-reactive protein, urinalysis, fecal occult blood test, and plain abdominal X-ray. The colonic examination will be indicated if these factors are positive. Note that positive fecal occult blood, anemia, hypoproteinemia, or positive inflammatory reaction especially will require colonic examination. The colonic examination is mainly colonoscopy. It is the clinician’s responsibility to perform an adequate examination to reach an accurate diagnosis. The guidelines do not guarantee 100% exclusion of unexpected organic diseases. Depending on the clinical situation, the following examinations may be indicated: gastrointestinal mucosal biopsy, upper gastrointestinal endoscopy, barium enema, upper gastrointestinal series, abdominal ultrasonography, fecal ova test, stool bacterial culture, abdominal computed tomography, computed tomographic colonography, abdominal magnetic resonance imaging, small intestinal endoscopy, small intestinal fluoroscopy, lactose tolerance test, and hydrogen breath test. If clinical examinations results are negative and the Rome IV criteria are positive, a diagnosis of IBS is made. If the Rome IV criteria for IBS are negative, patients may be classified into other functional gastrointestinal disorders (FGIDs)

Fig. 2

Step 1 of the IBS Therapeutic Algorithm. Subtyping of IBS is necessary at the time of treatment. Based on the Rome IV criteria, patients are classified as IBS with predominant diarrhea (IBS-D), IBS with mixed bowel habits (IBS-M), IBS unclassified (IBS-U), or IBS with predominant constipation (IBS-C). Moreover, the most bothersome symptoms including diarrhea, abdominal pain, or constipation may be targeted. See the main text for further details

Fig. 3

Step 2 of the IBS Therapeutic Algorithm. This step is indicated for IBS patients with moderate severity who do not respond to gut-targeted pharmacotherapy. For further details see the main text. Detailed examination described in the legend of Fig. 1 may be part of this step depending on the clinical demand

Fig. 4

Step 3 of the IBS Therapeutic Algorithm. Severe IBS patients who do not respond to conventional pharmacotherapy are treated in this step. See the main text for further details. Gastrointestinal dysfunction can be determined with gastrointestinal transit study, anorectal manometry, colonic manometry, or colorectal barostat examination