In-patient assessment of difficult diarrhoea

'Diarrhoea' remains a common problem presented to gastroenterologists. Assessment of the history will in most cases point to the investigations that will distinguish between organic and functional causes and lead to diagnosis. There exists a small group of patients either in whom there may be difficulties in distinguishing between organic and functional causes, or in whom a diagnosis of factitious diarrhoea is suspected. These patients should be admitted for a short in-patient assessment and undergo an analysis of 72-h stool weights. If these are less than 225 g/ day a functional cause should be suspected. If they are raised, then further investigations to exclude a factitious cause should include analysis of fluid balance, stool osmolality and stool electrolyte and creatinine content. A laxative screen should also be performed according to available quality control guidelines.