Gastrointestinal Disorders

Risk Factors for Bile Reflux and Bile Acid Malabsorption

Previous abdominal surgery, particularly cholecystectomy, increases the risk of bile reflux, as suggested by the American Gastroenterological Association 1, 2
A history of inflammatory bowel disease, especially with terminal ileal resection, is a risk factor for bile reflux 2
Radiation therapy to the abdomen or pelvis may contribute to the development of bile reflux 3
Post-infectious diarrhea is a risk factor for bile acid malabsorption, with a significant prevalence of bile acid malabsorption in patients with this condition 4
Patients with chronic diarrhea, particularly those with diarrhea-predominant IBS or functional diarrhea, are at risk for bile acid diarrhea, with up to 30% having this condition 5, 1

The European Society of Gastrointestinal Endoscopy recommends upper endoscopy to visualize bile reflux and assess for mucosal damage 1
The 75-selenium homocholic acid taurine (SeHCAT) scan is the gold standard test for diagnosing bile acid malabsorption, with retention values indicating mild (10-15%), moderate (5-10%), or severe (0-5%) bile acid loss, as recommended by the American Gastroenterological Association 6, 5
Measurement of total bile acids in a 48-hour stool collection is an alternative diagnostic option, with a threshold of >2300 μmol/48 hours indicating bile acid malabsorption 6, 5
Serum fibroblast growth factor 19 (FGF19) measures defective feedback of bile acid synthesis, with low levels suggesting bile acid malabsorption 6
Serum 7α-hydroxy-4-cholesten-3-one (C4) measurement is another diagnostic option, with a diagnostic threshold of >47.1 ng/mL and a 95% negative predictive value compared to SeHCAT 5

The American College of Gastroenterology recommends bile acid sequestrants, such as cholestyramine, colestipol, and colesevelam, for the treatment of bile acid malabsorption 1, 2
Initial evaluation should rule out other causes of chronic diarrhea, including screening for celiac disease, testing for inflammation, and testing for Giardia 6, 5
Colonoscopy with biopsies should be considered to exclude microscopic colitis 5
The American Gastroenterological Association conditionally recommends testing for bile acid diarrhea in patients with chronic diarrhea, reflecting the low quality of evidence but recognizing the importance of identifying this treatable condition 6
The British Society of Gastroenterology recommends using SeHCAT testing or serum C4 measurement for diagnosis, rather than empiric treatment trials, and strongly recommends against empiric trials of bile acid sequestrants without diagnostic testing 5
Positive test results should lead to initiation of bile acid sequestrant therapy, while negative test results should prompt investigation of other causes of diarrhea 5
Even with confirmed bile acid diarrhea, additional diagnoses such as bacterial overgrowth, pancreatic insufficiency, and microscopic colitis should be considered if symptoms persist despite treatment 5
Lack of response to cholestyramine does not exclude bile acid diarrhea, and alternative sequestrants like colesevelam should be considered 5