High sugar worse than high sodium in oral rehydration solutions

The literature on oral sugar-electrolyte mixtures for treatment of acute diarrhoea is reviewed. Several trials have shown that the solution proposed by the WHO for developing countries containing inter alia 90 mmol/l of sodium and 111 mmol/l of glucose is safe for short term oral rehydration. When used in this manner there is no risk for development of hypernatraemia. The surplus base of the solution is not essential and, furthermore, other anions e.g. acetate may be substitute for bicarbonate. Other modifications of the WHO formula have also been successfully tried, e.g. sucrose 4% (117 mmol/l) instead of glucose 2% (111 mmol/l). A somewhat lower concentration of sucrose may, however, prove to be better. Most acute childhood diarrhoeas are not mediated by enterotoxin and thus not of the secretory type, but temporary malabsorption is common. Therefore, the amount of carbohydrate in oral sugar-electrolyte mixtures should be limited. Osmotic diarrhoea due to carbohydrate malabsorption is a more likely cause of hypernatraemia in dehydrated children than too much dietary sodium. In developed countries prepacked oral sugar-electrolyte mixtures are mainly designed for moderately sick children treated at home. There is no reason to raise the carbohydrate content of these mixtures above that of the WHO formula, but the sodium content must be lower. For most situations in home treatment 50 mmol/l of sodium will be adequate.