Sodium homeostasis in neonatal infection of eutrophic premature infants

In 14 premature infants suffering from bacterial sepsis during the first week of life the daily renal sodium and potassium losses as well as the concentrations in serum of both electrolytes were measured before and during the period of infection. 24 hours before appearance of first clinical symptoms of sepsis the sodium concentration in urine increases and the balance becomes negative. Hyponatraemia occurs later and is in correlation with the clinical course of the disease. Thus, the hyponatraemia is caused more by shifting of sodium from the extracellular space than by renal sodium excretion. To prevent this hyponatraemia the sodium intake has to be increased to 6 mmol/kg X 24 h as a minimum and the fluid intake has to be decreased to 80 ml/kg X 24 h as a maximum in the same time when antibiotic treatment is started. A short-term control of serum electrolytes is an important premise for a sufficient treatment. Increased sodium concentrations in urine of more than 50 mmol/l or again increasing concentrations beyond the second day of life can be appreciated as early signs of neonatal sepsis.