Recent advances in the understanding of bile acid malabsorption.

INTRODUCTION: Bile acid malabsorption (BAM) is a syndrome of chronic watery diarrhoea with excess faecal bile acids. Disruption of the enterohepatic circulation of bile acids following surgical resection is a common cause of BAM. The condition is easily diagnosed by the selenium homocholic acid taurine (SeHCAT) test and responds to bile acid sequestrants. Idiopathic BAM (IBAM, primary bile acid diarrhoea) is the condition where no definitive cause for low SeHCAT retention can be identified. SOURCES OF DATA: Review of PubMed and major journals. AREAS OF AGREEMENT: Evidence is accumulating that BAM is more prevalent than first thought. Management of chronic diarrhoea involves excluding secondary causes. Treatment of the condition is with bile acid binders. AREAS OF CONTROVERSY: SeHCAT testing is not widely performed, limiting awareness of how common this condition can be. The underlying mechanism for IBAM has been unclear. GROWING POINTS: Increasing awareness of the condition is important. Alternative mechanisms of IBAM have been suggested which involve an increased bile acid pool size and reduced negative feedback regulation of bile acid synthesis by FGF19. New sequestrants are available. AREAS TIMELY FOR DEVELOPING RESEARCH: Further research into the precise mechanism of IBAM is needed. Improvements in the recognition of the condition and optimization of treatment are required.