Chronic diarrhoea due to bile salt malabsorption: nurse-led assessment, medical treatment and dietary management

Abstract

Bile salt malabsorption (BSM) occurs when bile salts, which are secreted in the small bowel to aid digestion of fats and vitamins, are not sufficiently re-absorbed in the terminal ileum. Consequently, an excess of bile salts enters the colon, causing chronic explosive diarrhoea, associated with abdominal cramps, flatulence and urgent, frequent and unpredictable bowel habits. BSM affects around 1% of the population, often occuring in ileal Crohn's disease or after ileal resection. Diagnosis begins with a nurse-led assessment, including blood and stool tests, to exclude other potential organic causes of chronic diarrhoea. BSM can then be confirmed and classified with a75Se-homocholic acid taurine (SeHCAT) scan. BSM can be treated medically with bile salt sequestrants, including colestyramine sachets, which are approved but have an unpleasant taste, and colesevelam tablets, which are more tolerable but more expensive and not yet approved. However, long-term sequestrant use can impact absorption of vitamins and other medications. BSM can also be managed with a low-fat diet, which is cost-effective and can reduce the amount of bile secreted. Nurses should provide patient education to ensure adherence and safe use.