Early clinical diagnosis of the syndrome of inappropriate secretion of antidiuretic hormone. Case reports.

Two children with inappropriate antidiuretic hormone secretion associated with meningococcal septicaemia are described. The syndrome was diagnosed despite the patients' serum sodium concentrations being within the normal range when, with normal fluid intake and in the absence of hypovolaemia, they developed oliguria and concentrated urine. Early diagnosis prevents cerebral water intoxication and pulmonary oedema that may occur if hyponatraemia is allowed to develop.