Protracted diarrhoea: secondary monosaccharide malabsorption and zinc deficiency with cutaneous manifestations during total parenteral nutrition.

Protracted diarrhoea in early infancy gives rise to many diagnostic and therapeutic problems. Jejunal biopsy often reveals villous atrophy of varying degrees. Severe reduction of small intestinal absorptive area causes secondary monosaccharide malabsorption, as well as secondary disaccharide deficiency, consequences which are relevant in any attempts at oral feeding. Morphologic, metabolic, endocrinological and microbiological studies have to be undertaken in order to establish a definitive diagnosis in protracted diarrhoea, but these studies often fail to reveal the aetiology of the disease. Immunologic abnormalities like phagocyte dysfunction, thymic atrophy and hypoplasia of B-cell regions in lymph nodes might be secondary events, but some types of immunodeficiency are of primary importance in the development of protracted diarrhoea. Total parenteral nutrition in many cases has to be instituted, with all its implications and hazards: septicaemia is the most dangerous of these. Zinc deficiency and acrodermatitis enteropathica may occur during total parenteral nutrition, and zinc deficiency secondarily contributes to the symptoms of diarrhoea. Parenteral administration of zinc is able to overcome these effects.