[A case of postoperative hyponatremia caused by Sheehan syndrome associated with lung carcinoma]

A 54-year-old woman underwent a left upper lobectomy for lung carcinoma after which hyponatremia developed within 5 days. Her serum concentration of ADH was within normal range disapproving the presence of SIADH frequently associated with lung carcinoma. An endocrinological examination showed panhypopituitarism. From her anamnesis it was seen that there was much perinatal bleeding and amenorrhea. She was diagnosed as suffering from Sheehan syndrome. She was treated with glucocorticoid and beneficial results were obtained. Her serum concentration of natrium returned to normal and she discharged on the 74th postoperative day. We present this paper because we had difficulty in determining that she had Sheehan syndrome, and think that a careful search for a diagnosis before operation is important for the management of the patient during the perioperative and postoperative period.