Evidence-Based Clinical Guidelines for Chronic Diarrhea 2023

Abstract

The Japan Gastroenterological Association (JGA) published the first version of clinical guidelines for chronic diarrhea 2023. These guidelines describe the definition, classification, diagnostic criteria, diagnostic testing methods, epidemiology, pathophysiology, and treatment of chronic diarrhea, and provide flowcharts for the diagnosis and treatment of chronic diarrhea based on the latest evidence. Treatment for chronic diarrhea begins by distinguishing secondary chronic constipation with a clear etiology, such as drug-induced diarrhea, food-induced diarrhea, systemic disease-associated diarrhea, infection-associated diarrhea, organic disease-associated diarrhea, and bile acid diarrhea. The first line of treatment for chronic diarrhea in the narrow sense, defined in these guidelines as functional diarrhea in routine medical care, is lifestyle modification and dietary therapy. The first medicines to be considered for oral treatment are probiotics for regulating the gut microbiome and anti-diarrheals. Other medications, such as 5HT3 receptor antagonists, anticholinergics, Kampo medicine, psychotherapy, antibiotics, bulking agents, adrenergic agonists, and somatostatin analogs, lack sufficient evidence for their use, highlighting a challenge for future research. This Clinical Guidelines for Chronic Diarrhea 2023, which provides the best clinical strategies for treating chronic diarrhea in Japan, will also be useful for medical treatment worldwide.

Keywords: Chronic diarrhea; Diarrhea-predominant irritable bowel syndrome; Functional diarrhea; Guidelines.

Fig. 1.

Initial medical treatment strategy for chronic diarrhea. First, the patients with chronic diarrhea are assessed through medical interviews, physical findings, blood tests. Drug-induced diarrhea and food-induced diarrhea are differentiated. Subsequent studies including stool examinations, computed tomography, colonoscopy, esophagogastroduodenoscopy were conducted to rule out systemic disease-associated diarrhea, infection-associated diarrhea, organic disease-associated diarrhea. Bile acid diarrhea is then excluded. The remaining patients are likely diagnosed with functional diarrhea or diarrhea-predominant IBS. This guideline defines chronic diarrhea in a narrow sense. IBS, irritable bowel syndrome.

Fig. 2.

Medical treatment strategy for chronic diarrhea (narrow sense) Initially, improvement in lifestyle habits and continuation of dietary therapy are recommended. If these prove ineffective, probiotics and antidiarrheal medications are administered. Should these have a poor response, the possibility of secondary chronic diarrhea should be reconsidered. Once secondary chronic diarrhea is ruled out, treatment options include 5HT₃ receptor antagonists, anticholinergics, Kampo medicines, psychotherapy, antibiotics, bulking agents, adrenergic agonists, somatostatin analogs, although their efficacy may be unclear.