Endocrine Abstracts

Introduction: Transnasal adenomectomy is the main treatment for various pituitary adenomas. The hypothalamic-pituitary region is the site of synthesis and secretion of several hormones that have a direct effect on sodium-water metabolism, which leads to its frequent violation with the development of central diabetes insipidus and severe transient hyponatremia, the latter of which is the second most important cause of rehospitalization in the postoperative period. Currently, the causes and factors predisposing to the development of this complication have not been identified.

Objective: To study the perioperative dynamics of apelin and copeptin neuropeptides after transnasal transsphenoidal adenomectomy for pituitary adenomas.

Materials and methods: The study included 22 patients who underwent transnasal adenomectomy for pituitary adenoma (inactive pituitary adenoma - 8 patients, acromegaly - 8 patients, Cushing’s disease - 6 patients, 6 men and 16 women, median age 52 years [Q25 39; Q75 62]), 10 of whom developed hyponatremia (group 1) with a median serum sodium of 125 mmol/l and 12 did not have any fluid and electrolyte disturbances (group 2). All patients were tested for serum Na, plasma apelin 12 (ELISA, Phoenix) and copeptin (ELISA, Phoenix) at 24 hours before surgery, 24 hours, days 2-3, 5 and 7 after surgery.

Results: The debut of hyponatremia was observed in the period 5-7 days after the operation. In both groups, there was a change in the level of copeptin with a decrease on days 2–3 after surgery and a further increase in group 1 and a decrease in group 2 by day 5 after surgery and returning to baseline values on day 7 after surgery. The level of apelin had different dynamics in the groups: in group 1, it decreased on the first day with a further increase with a maximum on day 5 and a return to the original values on day 7; in group 2, no statistically significant changes were recorded.

Conclusions: Transnasal adenomectomy is the cause of severe hyponatremia in the genesis of which, apparently, the hypothalamic neuropeptides copeptin and apelin play the leading role. The secretion dynamics of these neuropeptides changes reciprocally in groups with and without the development of hyponatremia, which makes them potential hormonal markers of this severe complication.