[Cerebral salt loss as Schwartz-Bartter-syndrome in childhood (author's transl)].

Schwartz-Bartter-syndrome as a consequence of severe cerebral alterations like bacterial and tuberculous meningitis, encephalitis, hydrocephalus and brain haemorrhage has been observed in 7 cases. Massive natriuresis is followed by marked hyponatremia and hypochloremia which may lead to an intracellular brain edema. Sodium administered even in high dosage is lost rapidly through the kidney, and does not normalize the serum level of sodium. The Schwartz-Bartter-syndrome is caused by inadequatly elevated ADH-secretion with consecutive water retention and an increase in plasma volume. Consecutively an increased excretion of sodium takes place causing a substantial loss of bound water. An analogous situation was seen in a child with neurohormonal diabetes insipidus after an overdosage of ADH, which resulted in a hypervolemia, marked hyponatremia and massive natriuresis. The increased excretion of sodium may be the result of reduced reabsorption of sodium in the proximal tubuli of the kidney, caused by a humeral natriuretic factor (the socalled "third factor"). In the serum of one of our patients an increased natriuretic activity could be shown; this is the first time in a child with Schwartz-Bartter-syndrome.