Introduction Bile acid malabsorption (BAM) is diagnosed by a reduced day 7 retention of bile acid at tauroselcholic [75selenium] acid (SeHCAT) scan. Currently there is little consensus on its use in the diagnosis of BAM in patients with unexplained diarrhoea . At our site, we have adopted a “test and treat” strategy rather than empirical therapy with bile acid sequestrants in patients with unexplained diarrhoea.
In this retrospective study, we have examined the diagnostic yield of SeHCAT in our clinical practice.
Method Patients who underwent SeHCAT scans between December 2012 to March 2016 were included in the study. Patients who had incomplete scans were excluded.≤15% bile acid retention at day 7 was regarded as mild BAM, ≤10% retention as moderate BAM, and ≤5% retention as severe BAM. Clinic letters were subsequently reviewed to ascertain causes of BAM.
Results SeHCAT scans were performed on 332 patients during the study period. One patient was excluded due to incomplete scan. Of the remaining 331 patients, 174 (53%) patients had normal scans, and 157 (47%) were diagnosed with BAM (63 severe, 43 moderate, 51 mild). Of the 157 patients who were diagnosed with BAM, 93 (59%) were type 2 (Idiopathic), followed by 39 (25%) type 1 (Terminal ileal pathology) and 25 (16%) type 3 (Other GI causes). Because of the size of the subgroups, further analysis was not possible.
Conclusion A high proportion (47%) of those who underwent SeHCAT scan were diagnosed with BAM. This exceeds the recently published meta-analysis data on the prevalence of BAM (16.9%>35.3%, pooled rate 28.1%) . This may be because of a higher than usual pre-test probability since all patients had already undergone comprehensive investigations for other causes of chronic diarrhoea.
Type 2 BAM predominated (60%) and the majority had mild or moderate malabsorption. Anecdotally, response rates to therapy in this group are variable and we have noticed that diagnostic confidence may increase patient compliance and satisfaction with treatment. This retrospective data seems to support a “test and treat” strategy in the management of bile acid diarrhoea.
. NICE diagnostic guidance DG7 (Nov 2012, reviewed Nov 2015)- SeHCAT for the investigation of diarrhoea due to bile acid malabsorption in people with diarrhoea-predominant irritable bowel syndrome (IBD-D) or Crohn’s disease without ileal resection.
. Slattery SA, et al. Systematic review with meta-analysis: The prevalence of bile acid malabsorption in the irritable bowel syndrome with diarrhoea. Alimentary Pharmacology and Therapeutics, 2015Jul;42(1):3–11.
Disclosure of Interest None Declared
- bile acid malabsorption