Treating hyponatremia in an empty sella syndrome patient complicated with possible myelinolysis

Hyponatremia as the presenting manifestation of empty sella syndrome is rare. There is little clinical experience in the management of this problem and its possible therapeutic complications. We herein report on a 44-year-old woman with a past history of massive postpartum hemorrhage who was admitted because of hyponatremia and disturbed consciousness. Initial biochemical data suggested the effects of antidiuretic hormone, but fluid restriction alone offered limited benefit. Later, hormonal levels indicated hypopituitarism. Magnetic resonance imaging and cisternography led to a diagnosis of empty sella. Although glucocorticoid substitution was initiated and the clinical condition initially improved, possible myelinolysis subsequently became a complication. With early recognition and immediate replacement of hypotonic fluid, the patient completely recovered. We report this case to illustrate the fact that glucocorticoid substitution and concurrent fluid restriction can probably lead to myelinolysis in empty sella syndrome patients. We suggest that the serum sodium level should be frequently monitored and that much more attention should be paid to the neurologic signs when substituting glucocorticoids in these patients, even though the increment in the serum sodium level is acceptable. Once possible myelinolysis develops, early recognition is critical, and the immediate replacement of hypotonic fluid is suggested.