[The Schwartz-Bartter syndrome]

Nine children with Schwartz-Bartter-syndrome are described. Seven suffered from severe diseases of the CNS, 2 developed the syndrome during treatment with vincristine, the damaging action of which on the CNS is known. The main symptoms of the syndrome are: hyponatremia with consecutive hypotonia of the extracellular space caused by excessive urinary sodium loss. The plasma volume is not diminished. Therapeutically administered NaCl appears in the urine which is hyperosmolar in spite of the hypoosmolarity of the plasma. The increased secretion of ADH which Schwartz et al. postulated to be the cause of the syndrome has been confirmed in recent years. The organism attempts to excrete the increased fluid volume which is retained by ADH, probably by means of a natriuretic hormone, so-called third factor. Enhanced activity of such a factor was assessed in one of our cases.