Sodium and water regulation in a patient with cerebral salt wasting
M. Diringer, P. W. Ladenson, C. Borel, G. K. Hart, J. R. Kirsch and D. F. Hanley
Department of Neurology, Neuroscience Critical Care Unit, Johns Hopkins Medical Institutions, Baltimore, MD 21205.
Hyponatremia, in patients with central nervous system disease, can be
attributable to impaired free water excretion (syndrome of inappropriate
secretion of antidiuretic hormone) or to excessive sodium excretion
(cerebral salt wasting). We present a patient with a parietal glioma and
hyponatremia characterized by salt wasting and dehydration. Rehydration and
sodium repletion corrected the sodium and volume deficits; withdrawal of
supplemental sodium resulted in recurrence of dehydration and hyponatremia.
We determined sodium and water balance and measured plasma atriopeptin,
antidiuretic hormone, and aldosterone. Plasma atriopeptin ranged from 8 to
44 pg/mL (normal, less than 45 pg/mL); antidiuretic hormone was not
elevated at 4 to 5 pg/mL, and aldosterone was slightly elevated at 1040.25
pmol/L. The concentrations of these hormones could not directly explain the
natriuresis; interactions with neural or other humoral factors may be
involved. In evaluating such patients, careful attention to sodium and
water balance is important to guide appropriate therapy.
