[A 78 year-old man with hyponatremia, malaise and weight loss caused by a pituitary mass].

A 78 year-old male was admitted for rehabilitation after a trans-tibial amputation three months earlier. Scheduled training with a prosthetic leg was postponed due to muscle atrophy and weakness. As the patient's status deteriorated, blood results showed worsening hyponatremia.Work-up revealed pituitary insufficiency caused by a pituitary mass. The patient's general health improved greatly and the hyponatremia corrected after hormonal replacement therapy with hydrocortisone, thyroxin and testosterone was initiated. Key words: hyponatremia, malaise, weight loss, pituitary insufficiency, pituitary adenoma.