Infantile diarrhoeal dehydration treated with adrenal cortical hormone and potassium chloride.

Dehydration is the danger signal of infantile diarrhoea because without dehydration the mortality from properly treated gastro-enteritis should be negligible, hence the importance of preventing dehydration and the recognition that its presence indicates a medical emergency. Important constituents of both extracellular and intracellular body fluids are the electrolytes, and Gamble (1947) considers the term ' dehydration ' incomplete because it fails to indicate, as was shown by McIntosh, Kadji, and Meeker (1931), that water loss is always accompanied by loss of electrolyte. It folows that therapeutic repair cannot be effective unless both water and electrolyte are replaced. Electrolytes are dissociated within the body; for example, sodium chloride is present as separate sodium ions and chloride ions. With diarrhoea there is an excessive excretion of water, protein, chloride, sodium and bicarbonate ions (mainly extracellular electrolytes), and potassium and magnesium ions (mainly intracellular electrolytes). Over 30 years ago Holt, Courtney, and Fales (1915) showed that diarrhoeal stools contain much larger amounts of water and electrolyte than do normal stools, and they expressed the view that a better solution than the Ringer's and normal saline then in use could be devised for parenteral therapy. Prolonged electrolyte loss produces dehydration (Gamble, 1947; Darrow, 1944; Darrow, 1947a); this was confirmed experimentally in animals by Darrow and Yannet (1935). Until recently the cell membrane was believed to be impermeable to the passage of electrolyte and that therefore only extracellular electrolyte could be replaced. Darrow and others found, however, that potassium and sodium do penetrate cell membranes. This led to the introduction by Darrow of his sodium-potassiumchloride solution as a therapeutic measure for the replacement of intracellular as well as extracellular