Electrolyte metabolism in rhesus monkeys with experimental salmonella sepsis

Prior investigations in the human indicate that alterations occur in electrolyte balance and serum concentration during infectious diseases. In order to explore these alterations in greater detail, electrolyte metabolism has been investigated in rhesus monkeys with a sublethal illness induced by intravenous inoculation with Salmonella typhimurium. The response to this illness was evaluated by a variety of measurements including serum and muscle electrolyte composition and renal function studies. In the animals with ad libitum dietary intake, a loss in muscle and serum potassium concentrations was evident within 24 h after inoculation. This was reflected in increased urinary potassium losses during the febrile phase of illness. Serum and muscle K concentrations returned to normal after 5 days of illness. Sodium and water content of muscle responded to infection in a more complex pattern. During the febrile phase, muscle sodium and water increased and sodium concentrations in serum and urine were elevated. During convalescence, renal retention of sodium was marked and overlapped the period of weight loss and the increased urine volume. This asynchrony in recovery of normal renal function appeared to be the cause of relatively large swings in plasma sodium concentrations during the early convalescent period. These investigations indicate that the altered serum concentrations in infectious diseases are the sum of renal and extrarenal factors controlling electrolyte metabolism, and that some of the most remarkable alterations occur during early convalescence as renal function returns to normal.