Isolated ACTH deficiency in a patient with empty sella as revealed by severe hyponatremia.

Hyponatremia due to isolated adrenocorticotropic hormone (ACTH) deficiency is difficult to diagnose as it is usually indistinguishable from non-endocrine syndrome of inappropriate antidiuretic hormone secretion (SIADH). We present a case secondary to empty sella. Most patients with empty sella remain asymptomatic throughout life and require no treatment; however, in cases involving the development of isolated ACTH deficiency, corticosteroid treatment should be enforced to avoid fatal consequences.