Background: Idiopathic bile acid malabsorption is a poorly recognized
cause of chronic diarrhoea. The SeHCAT ((75)Selenium HomotauroCholic A
cid Test) can accurately diagnose this condition. Aim: To identify pat
ients with idiopathic bile acid malabsorption, to describe their clini
cal features, both qualitatively and quantitatively, and to assess the
response to cholestyramine, Method: Idiopathic bile acid malabsorptio
n was considered in all patients complaining of chronic diarrhoea. The
y were included in the study if their SeHCATs were positive (< 15% ret
ention) and secondary causes of bile acid malabsorption were excluded.
The response to therapy with cholestyramine was assessed. Results: Ni
ne patients were diagnosed with idiopathic bile acid malabsorption (me
dian SeHCAT retention 8%, range 3-12.6), Their median daily faecal wei
ght was 285 g (range 85-676) and median faecal fat output was 17 mmol/
24 h (range 8.3-38.8), Six patients had an immediate response to chole
styramine. There was a marked reduction in stool frequency (median sto
ol frequency pre-treatment 5/day vs, 2/day post-treatment, P = 0.03).
Five patients had large volume diarrhoea (faecal weight > 200 g/day) a
nd three had steatorrhoea, Conclusions: Idiopathic bile acid malabsorp
tion, once suspected, especially by documenting true 'large volume' wa
tery diarrhoea pr steatorrhoea, is easily diagnosed and response to th
erapy is often very good, There is often a previous history of gastroi
ntestinal infection and this condition should be considered in patient
s with chronic diarrhoea of undetermined origin, especially before the
y are labelled as having irritable bowel syndrome.