Misinterpreting Diarrhea-Predominant Irritable Bowel Syndrome and Functional Diarrhea: Pathophysiological Highlights

• Published in: Journal of clinical medicine Vol. 12; no. 18; p. 5787
• Main Authors: Sciumè, Giusi Desirè, Berti, Ginevra, Lambiase, Christian, Paglianiti, Italia, Villanacci, Vincenzo, Rettura, Francesco, Grosso, Antonio, Ricchiuti, Angelo, Bortoli, Nicola de, Usai Satta, Paolo, Bassotti, Gabrio, Bellini, Massimo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2023; MDPI
• Subjects: Abdomen; Acids; BAM; Bile; bile acid malabsorption; Bile acids; Biopsy; Case reports; Clinical medicine; Colitis; Development and progression; Diagnosis; Diarrhea; Feces; Fibroblasts; Growth factors; IBS; Inflammatory bowel disease; Irritable bowel syndrome; microscopic colitis; Quality of life; Retention; Review; Small intestine; Type 2 diabetes; Iran
• ISSN: 2077-0383; 2077-0383
• DOI: 10.3390/jcm12185787

Irritable bowel syndrome with predominant diarrhea (IBS-D) and functional diarrhea (FD) are disorders of gut–brain interaction characterized by recurring symptoms which have a serious impact on the patient’s quality of life. Their pathophysiology is far from being completely understood. In IBS-D growing evidence suggests that bile acid malabsorption (BAM) could be present in up to 30% of patients. Microscopic colitis (MC) is a well-known cause of watery diarrhea and some patients, at first, can be diagnosed as IBS-D or FD. Both BAM and MC are often responsible for the lack of response to conventional treatments in patients labelled as “refractory”. Moreover, because BAM and MC are not mutually exclusive, and can be found in the same patient, they should always be considered in the diagnostic workout when a specific treatment for BAM or MC is unsatisfactory. In the present review the possible shared pathogenetic mechanisms between BAM and MC are discussed highlighting how MC can induce a secondary BAM. Moreover, a brief overview of the current literature regarding the prevalence of their association is provided.