Bile acid malabsorption or bile acid diarrhoea
In bile acid diarrhoea, the bile acids formed in the liver are not reabsorbed through blood circulation. An excess amount of bile acid enters the colon and causes irritation, further leading to diarrhoea. Thus, bile acid diarrhoea is also known as bile acid malabsorption.
The symptoms of bile acid diarrhoea include chronic and prolonged watery stools as well as sudden tenesmus. The excess bile acids that enter the colon cause watery stools by affecting the function of the colon lining resulting in the secretion of water and salts, increasing the intensity of bowel contractions and accelerating colonic transit. Other typical symptoms include frequent bowel movements and often during the night, foul-smelling diarrhoea, which has a yellow or fatty appearance, intense flatulence, painful abdominal cramps, bloating, fatigue and poor energy levels, nausea and digestive disorders.
The underlying cause of bile acid malabsorption may include, for example, a chronic infection of the ileum, intestinal damage caused by radiotherapy, ileocecal resection, cholecystectomy or ileocecal valve resection. Approximately 10-15 per cent of people living with IBS that causes increased diarrhoea are diagnosed with reduced bile acid absorption. In this case, bile acids enter the colon due to accelerated small intestine transit. Therefore, bile acid diarrhoea may be misdiagnosed as IBS.
Bile acid diarrhoea is primarily diagnosed with medication trials in which any changes to symptoms are monitored in response to bile acid sequestrants. The diagnosis can also be carried out with imaging. The treatment of bile acid diarrhoea focuses on easing the symptoms with bile acid sequestrants. A low-fat diet may also help with reducing symptoms. Diarrhoea usually passes in a few days, and finding the correct medication dose and modifying diet habits may take time.