Hypernatraemia surveillance during a national diarrhoeal diseases control project in Egypt

The nationwide introduction of oral rehydration therapy to Egypt has led to improvement in diarrhoea case management and a fall in infant and child mortality. With the wider use of oral rehydration solution (ORS) prepared from packets, the incidence of hypernatraemia (serum sodium greater than 150 mmol/l) in inpatients with dehydration seen at Abu El-Reeche Hospital, Cairo, increased between 1980 and 1984. Systematic surveillance of hypernatraemia in the outpatient rehydration unit began in late 1984, and we report trends in hypernatraemia and analyses of key variables affecting its incidence in dehydrated children. In 1980, 17 of 100 children sampled had hypernatraemia and 2 had severe hypernatraemia (ie, serum sodium greater than 165 mmol/l). The frequency in inpatients peaked at 49% of 222 children in 1984 (19% with severe hypernatraemia). Between 1986 and 1989, at least 1000 dehydrated outpatients were surveyed each year; by 1989 the incidence of hypernatraemia had fallen to around 10% (2% severe hypernatraemia). The rise and decline coincided with increasing use of ORS and then increasing ability of mothers to mix the solution correctly. Hypernatraemia was positively related to the quantity of ORS taken, severity of dehydration, nutritional status, and the cooler season, and negatively related to age and duration of diarrhoea. Explanations for our findings include improved use of ORS and better case-management. Good practice promoted through the mass media has facilitated these changes; if the standard of ORS use is not maintained, there may be a case for reducing the sodium content of ORS.