Colonic fluid handling in health & acute diarrhoeal diseases

The ability of the colonic epithelium to actively absorb sodium against electrochemical gradients confers on it the capacity to dehydrate the faeces. This capacity is of considerable importance in limiting fluid losses in acute diarrhoeal illnesses characterised primarily by small intestinal fluid secretion. Even in these illnesses, colonic absorptive capacity may be altered for various reasons. Loss of colonic absorptive capacity is also responsible for diarrhoea in those illness where the pathology is primarily epithelial cell damage in the large bowel. The present review analyses the information available on this subject from studies in patients with acute diarrhoea, and in experimental animals. It also outlines measures that might possibly restore optimal function of the colonic salvage mechanism in acute diarrhoeal disease.