IDIOPATHIC BILE-ACID MALABSORPTION - LONG-TERM OUTCOME

Objective: Idiopathic bile acid malabsorption (IBAM) is a rare cause o f diarrhoea. The natural history of this disorder has not previously b een reported. The aim of our study was to determine the long-term outc ome in a cohort of patients with severe IBAM using a subjective assess ment and by measuring the proportion of Se-75-homocholic acid taurine ((75)SeHCAT) retained 7 days after its ingestion. Patients and methods : Twenty-three patients with IBAM were identified in 1989. All had res ponded well to treatment with a bile acid chelator (cholestyramine or aluminium hydroxide). Questionnaires relating to current clinical symp toms and prescriptions were sent to these patients and their general p ractitioners. (75)SeHCAT tests were performed for objective assessment . Results: Three patients were lost to follow-up, three had died owing to malignancy and three had been diagnosed as suffering from inflamma tory bower disease. The mean period of follow-up for the remaining fou rteen patients was 99.2 (range 48-140) months. Seven of the patients s howed an improvement in symptoms and no longer required treatment with cholestyramine. In the remaining seven symptomatic patients, diarrhoe a was well controlled by continued treatment with cholestyramine (five patients) or standard anti-diarrhoeal treatment (two patients). All s even symptomatic patients and three asymptomatic patients underwent re peat 7 day (75)SeHCAT tests. The test results in the asymptomatic grou p had all improved so that the retention of the tracer after 7 days wa s above 5%; all but two patients in the symptomatic group still had va lues under 5%. However, the small number of patients in both groups pr ecluded statistical analysis. Conclusions: IBAM is a rare cause of dia rrhoea and should be diagnosed only after malignancy and inflammatory bowel disease have been excluded by rigorous investigations. Patients should be followed up as some develop other serious gastrointestinal d iseases. fifty per cent of the patients in our survey have remitted sp ontaneously and no longer require medication with bile acid chelators or anti-diarrhoeal agents.