Bile acid diarrhea - as bad as it gets?

Abstract

Purpose of review: Bile acid diarrhea (BAD) is a common but under-recognized gastrointestinal condition that manifests with increased stool frequency and urgency, and a looser stool consistency. The aim of this review is to present recent advances in the pathophysiology, mechanisms, manifestations, diagnosis, and treatment of BAD.

Recent findings: Patients with BAD have evidence of accelerated colonic transit, increased gut mucosal permeability, altered stool microbiome composition, and decreased quality of life. Single, random stool measurements of bile acids, alone or in combination with fasting serum 7-alpha-hydroxy-4-cholesten-3-one, have shown good sensitivity and specificity for the diagnosis of BAD. Novel therapeutic approaches include farnesoid X receptor agonists and glucagon-like peptide 1 agonists.

Summary: Recent research has led to a better understanding of the pathophysiology and mechanisms of BAD, which might pave the way towards more targeted treatment strategies for BAD. Newer, more affordable, and easier diagnostic methods facilitate the diagnosis of BAD.

Figure 1.. ROC curve and odds ratio (95% CI) of significant predictors of clinical markers of diarrhea based on stool frequency (A), stool consistency (B), and diagnosing bile acid diarrhea (C).

Primary BA-SS: primary bile acid measured from the single stool sample; CDCASS: chenodeoxycholic acid measured from single stool sample; DCA-SS: deoxycholic acid measured from single stool sample; C4: 7a-hydroxy-4-cholesten-3-one; BSFS: Bristol Stool Form Scale; ROC: receiver operating characteristic; AUC: area under the curve; OR: odds ratio; CI: confidence interval. Reused with permission from reference (35) Vijayvargiya, P., Camilleri, M., Taylor, A., Busciglio, I., Loftus, E. V., Jr., & Donato, L. J. (2020). Combined Fasting Serum C4 and Primary Bile Acids From a Single Stool Sample to Diagnose Bile Acid Diarrhea. Gastroenterology, 159(5), 1952–1954.e1952. doi:10.1053/j.gastro.2020.07.001

Figure 2.. Suggested management algorithm for patients with symptoms suggestive of bile acid diarrhea.

*: symptoms suggestive of bile acid diarrhea include stool of liquid consistency, greater urgency and frequency of bowel movements. BA: Bile acid; BAD: bile acid diarrhea; TBA: total bile acids; serum 7αC4: 7a-hydroxy-4-cholesten-3-one; 1° BA: primary bile acids.