[Mechanism and therapy of hyponatremia with central origin].

The effect of therapy for hyponatremia with central origin (cerebrovascular disease and head injury) was investigated in order to examine contributing factors. Out of a total of 58 subjects admitted to the hospital during the previous three years with cerebrovascular disease (49 cases), and head injuries (9 cases), hyponatremia with central origin occurred within 2 weeks. Special treatment for hyponatremia was not given in 30 of the 58 cases (control group). The group (28 cases) which underwent therapy was optionally selected in terms of the following-SIADH, natriuretic polypeptide involvement and sick cells resulting from Na-K pump disorder. These 28 cases were classified into subgroups: water restricted (7 cases), hypertonic NaCl load (9 cases), glucose/insulin/potassium (GIK) therapy (4 cases), phenytoin administration (8 cases). In all of the 58 patients, the serum sodium, potassium and osmolarity and urinary sodium and potassium were measured daily. The balance of water, sodium and potassium were calculated on hyponatremic phase. Plasma levels of such hormones as antidiuretic hormone, aldosterone and cortisol were measured on hyponatremic phase. For each group, onset day and duration of hyponatremia and lowest sodium value were investigated for the sake of comparison. No significant difference for onset day and lowest sodium value was found between each group. Duration was as follows: control group 9.4 +/- 3.3 days, water restricted 7.4 +/- 2.1 days, hypertonic NaCl load 3.3 +/- 1.4 days, GIK therapy 7.3 +/- 2.9 days and phenytoin administration 8.9 +/- 3.7 days. Hypertonic NaCl load indicated a significantly shorter duration compared with the other groups. Hypertonic NaCl load was found to be most effective for hyponatremia with central origin.(ABSTRACT TRUNCATED AT 250 WORDS)