A case of hyponatremia caused by central hypocortisolism.

Background: A 43-year-old woman was referred to the Psychiatric Unit of the University of Florence Hospital, 1 year after the development of a clinical picture characterized by nausea, hyporexia, muscle weakness, insomnia, weight loss, amenorrhea and severe depression. These clinical manifestations had started 2 months after delivery of her first child. Initial laboratory investigations revealed hypoglycemia and hyponatremia. The patient was, therefore, transferred to the Endocrine Unit of the same hospital for further evaluation of the case.

Investigations: Physical examination to evaluate extracellular volume status, standard laboratory investigations, and evaluation of plasma and urinary osmolality and urinary sodium excretion. Basal and dynamic evaluation of anterior pituitary function and a pituitary MRI were also performed.

Diagnosis: Hyponatremia caused by central hypocortisolism (isolated adrenocorticotropic hormone deficit).

Management: Glucocorticoid therapy (25 mg cortisone acetate tablets, 1.5 tablets per day).