OBJECTIVETo clarify the frequency and presentation associated factors, pathogenetic mechanism, treatment and outcome of hyponatremia after surgery of pituitary adenoma.

METHODSRetrospectively reviewed the data of 186 patients who underwent pituitary surgery between January 1999 and June 2000 in the department.

RESULTS72 (38.7%, 72/186) patients had suffered post-operative hyponatremia. Among them, 43 (59.7%, 43/72) cases the hyponatremia appeared at 4 to 7 days postoperatively. 43 (59.7%, 43/72) cases presented with nausea, vomiting, headache, dizziness, confusion and weakness. The symptoms of hyponatremia was related to the age, tumor size and adenoma cell type, but not to the sex, surgical approach and degree of removal. Treatment consisted of salt replacement and mild fluid restriction in 4 patients and salt and fluid replacement in 68 patients. Hyponatremia had been resolved within 7 days in 63 patients.

CONCLUSIONSHyponatremia often appeared about 7 days after surgery of pituitary adenoma, especially in elderly and in patients with macroadenomas. The principle of treatment was salt and fluid replacement.