Investigating the Gut: Steatorrhoea

Steatorrhoea

Steatorrhoea is the result of fat malabsorption, with diagnosis usually ascertained from patient history. The hallmark of steatorrhoea is the passage of pale, bulky, and malodorous stools, which often float and are difficult to flush.

In healthy individuals, less than 6 g of fat is excreted daily in the stools. This amount remains stable irrespective of intake.

The most important first step in deciding whether to investigate possible steatorrhoea is to determine if the overall clinical picture suggests fat malabsorption. Fat malabsorption can have many causes including pancreatic insufficiency, diarrhoeal illnesses and coeliac disease. A history of oil drops that separate from the main stool mass, and become whitish and firm after cooling (non-hydrolysed triglycerides), strongly points toward pancreatic insufficiency as the cause.

Investigating steatorrhoea
Diagnosis made clinically
Faecal elastase
Faecal fat
Fat soluble vitamins

Faecal elastase test¹

• Most sensitive test for pancreatic insufficiency
• Elastase levels correlate with other pancreatic enzymes such as lipase, amylase and trypsin

Faecal fat test^2,3

• Not recommended
• Low sensitivity for pancreatic insufficiency
• Very unpleasant test

Fat soluble vitamins³

• In the first instance, the measurement of fat soluble vitamins is not indicated when investigating steatorrhoea, but may be recommended by a specialist
• Ongoing steatorrhoea can be associated with deficiency of fat soluble vitamins (A, D, E, K), as they are “trapped” by the unabsorbed fats

Further assessment at a specialist level will often be directed towards making a specific diagnosis rather than proving fat malabsorption.