What is osmotic diarrhoea and what are the causes?
Osmotic diarrhoea is a form of watery diarrhoea. It is caused by disordered water and electrolyte transport in the small intestine as a result of osmotic imbalance between the gut and the extracellular fluid. For example, reduced production of enzymes in a malnourished child may lead to slow absorption of sugars (e.g. sucrose, lactose) and, if present in sufficient quantity, these will exert a high osmotic load in the gut. To maintain osmotic balance, fluid passes from the body into the gut. This causes watery stools. (Note: osmotic diarrhoea is not common in malnutrition if children are given small frequent feeds, and if the sugar content is not too high).
