Alterations in plasma concentrations of natriuretic peptides and antidiuretic hormone after subarachnoid hemorrhage.
OBJECTIVE
Hyponatremia is a common complication after subarachnoid hemorrhage. In this study we investigated the relations among hyponatremia, plasma natriuretic peptides, and antidiuretic hormone concentrations after subarachnoid hemorrhage.


METHODS
Blood samples for radioimmunoassay measurement of plasma brain natriuretic peptide-like immunoreactivity, atrial natriuretic peptide-like immunoreactivity, and antidiuretic hormone were obtained every 2 to 4 days until day 14 after subarachnoid hemorrhage.


RESULTS
Eleven of 20 patients with verified subarachnoid hemorrhage demonstrated mild hyponatremia (126 mEq/L < serum sodium < 135 mEq/L) during their clinical course. Atrial natriuretic peptide and antidiuretic hormone concentrations were significantly elevated on days 0 to 2 after onset of subarachnoid hemorrhage. Atrial natriuretic peptide concentrations remained high in patients who developed mild hyponatremia on days 6 to 14 after onset of subarachnoid hemorrhage. In contrast, antidiuretic hormone concentrations became significantly lower during the second week in these patients.


CONCLUSIONS
Mild hyponatremia after subarachnoid hemorrhage may be attributable not to the syndrome of inappropriate secretion of antidiuretic hormone but to cerebral salt-wasting syndrome. Atrial natriuretic peptide may be a causal natriuretic factor in cerebral salt-wasting syndrome.
Department of Neurosurgery, School of Medicine, Tokyo Medical University, Japan.
E
E
Isotani
R
R
Suzuki
K
K
Tomita
M
M
Hokari
S
S
Monma
F
F
Marumo
K
K
Hirakawa
D000328:Adult; D000368:Aged; D009320:Atrial Natriuretic Factor / Q000097:blood; D001834:Body Water / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D045283:Natriuretic Agents / Q000097:blood*; D020097:Natriuretic Peptide, Brain; D009419:Nerve Tissue Proteins / Q000097:blood; D009994:Osmolar Concentration; D012964:Sodium / Q000097:blood; D013345:Subarachnoid Hemorrhage / Q000097:blood*; D014667:Vasopressins / Q000097:blood*
D045283:Natriuretic Agents; D009419:Nerve Tissue Proteins; D014667:Vasopressins; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor; D012964:Sodium