Small intestinal mucosal histology in the syndrome of persistent diarrhoea and malnutrition: a review.

Prolonged injury to the small intestinal mucosa is probably the final common pathway by which a variety of noxious influences--nutritional, infective and possibly allergic--perpetuate the syndrome of persistent diarrhoea in children in developing countries. Animal studies have helped to separate the individual effects of malnutrition and diarrhoea on the gut in a way that is not possible in the clinical situation. Early studies in children provided somewhat subjective or semi-quantitative data on intestinal morphology. More recently, the application of computer-assisted quantitative morphological techniques to intestinal mucosae from children with persistent diarrhoea have revealed a spectrum of changes consistent with a cell-mediated immune form of damage. The nature of the antigens that provoke these responses remains to be elucidated. Several reports indicate that in children with persistent diarrhoea clinical severity and prognosis do not necessarily correlate with the degree of small intestinal mucosal damage. Nutritional rehabilitation can be shown to produce a demonstrable improvement in small intestinal crypt cell proliferative activity in children with persistent diarrhoea. It is not yet known for how long nutritional rehabilitation should be continued to ensure complete recovery of the intestinal damage following persistent diarrhoea.