Abstract
Plasma atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH) levels were determined in patients with hypertensive intracerebral hemorrhage (HIH) and in those with cerebral infarction (CI), and their effects on hyponatremia were studied. The subjects were 19 cases of HIH and 11 cases of CI who were admitted to our hospital from March 1989 to March 1990. Serum electrolytes and plasma ANP and ADH were determined in acute stage on Day 1 to 4, in hyponatremia stage on Day 5 to 14, and in chronic stage on Day 15 and after. The serum sodium level of less than 130 mEq/l was taken as hyponatremia. The plasma ANP level in normal controls (n=20), who were admitted to the hospital for a close checkup, was 26.5 ± 11.6 pg/ml (10-50) and therefore, plasma ANP levels exceeding 50 pg/ml were regarded as abnormally high level. Four HIH cases showed hyponatremia, while none of CI had hyponatremia. Sites of the lesion in these HIH cases were putamen in 2 cases and subcortical area in 2 cases. Hyponatremia in HIH developed at average 7.7 hospital day and lasted for 4.9 days. The minimum serum sodium level was 129.3 mEq/1. The plasma ADH level increased in acute stage of HIH regardless of hyponatremia, decreased gradually thereafter, and became normal in hyponatremia stage. ADH level in CI cases remained unchanged during each stage. There was no significant difference in plasma ANP levels between HIH cases with and without hyponatremia. But ANP level in acute stage tended to persist to hyponatremia stage in cases with hyponatremia. In contrast, ANP level of CI in each stage was significantly higher than that in control cases. These were some cases having abnormally high level of ANP exceeding 50 pg/ml. Heart diseases were found in 6 out of 11 CI cases, and renal diseases were complicated in 2 cases. Plasma ANP levels in CI were thought to be high because of these complications. The results above suggest that it is difficult to predict the development of hyponatremia from plasma ADH and ANP levels in acute stage, and plasma ADH and ANP levels are not always abnormally high even at the onset of hyponatremia.
