Hyponatremia as a leading sign of hypopituitarism

We report the case of a 67-year-old man admitted to our hospital in an obtunded state. We found that a severe hyponatremia (115 mEq/L) was the cause of patient's status. In turn, hyponatremia was due to hypopituitarism (nonfunctioning macroadenoma). Mild to moderate hyponatremia had been previously detected in this patient, but it was overlooked. Correction of hyponatremia and treatment replacement therapy for central hypothyroidism and hypocortisolism restored a satisfactory clinical condition before discharge. The clinical onset of hypopituitarism is often characterized by mild nonspecific symptoms especially in older people, and it is often overlooked. Hypoglycemia can be another clue to undiagnosed hypopituitarism, and in the reported case, suspicious episodes of hypoglycemia occurred in the months preceding admission. Furthermore, several physicians consider hyponatremia as a normal consequence of aging. Although hyponatremia is a common electrolyte disorder in the elderly, physicians should not forget that it could be the leading manifestation of hypopituitarism. Hypopituitarism may be easily diagnosed, but clinical suspicion is needed. Because of the excess mortality associated with hypopituitarism, hormone assays should be included in the initial diagnostic work-up of hyponatremia.