Endocrine Abstracts

Objectives: To assess the frequencies of hyponatremia and central diabetes insipidus (CDI) after transnasal adenomectomy and to identify its risk factors.

Patients and methods: The study included 152 patients aged 18 to 65 years (median [Q1; Q3] 40 [31; 52]) who underwent endoscopic endonasal transsphenoidal surgery due to Cushing’s disease, acromegaly, prolactinoma, non-functioning pituitary adenoma, thyreotropinoma or Nelson’s syndrome at Endocrinology Research Centre in 2010-2011 years. All patients underwent clinical and laboratory examinations and were discharged on 10-14 days after surgery.

Results: Severe hyponatremia (116 mmol/l) developed in 2 patient (1.3%), moderate (127 mmol/l) in 1 patient (0.7%) on the 1^st-7^th day after surgery and in all cases it was reversed by fluid restriction. Mild transient hyponatremia (131-134 mmol/l) occurred in 8 patients (5.3%). Persistent CDI (pCDI) has developed in 34 patients (22.4%) with 3 cases of three-phase CDI (including 2 cases of three-phase CDI with mild hyponatremia), transient CDI (tCDI) occured in 25 (16.4%), 82 patients did not have any disturbances (53.9%) by discharge. Postoperative pCI and tDI were promoted by Cushing’s disease (odds ratio (OR) 2.5, 95% CI (1.1-5.6) for pDI, 3.6 (1.4-9.2) for tDI), whereas acromegaly decreased the risk (OR 0.3 (0.1-0.6) for pDI, 0.3 (0.1-0.8) for tDI)). Secondary adrenal insufficiency (OR 2.6 (1.2-5.9) for pDI, 3.1 (1.3-7.6) for tDI), microadenoma (OR 4.1 (1.6-10.6) for pDI, 5.2 (1.9-14.6) for tDI), MRI tumor’s volume <0,75 cm³ (OR 4.8 (1.8-12.6) for pDI, 7.5 (2.1-26.8) for tDI) and surgery pituitary injury (OR 4.1 (1.6-10.6) for pDI, 5.2 (1.9-14.6) for tDI) provoked pDI and tDI. Postoperative DI was also more common at trend level in patients with adrenocorticotropic hormone levels of <16,5 pg/ml and cortisol level of <228 nmol/l and pDI was more often associated with secondary hypothyroidism at trend level as well.

Conclusions: The proportion of hyponatremia was 7.3%, persistent postoperative CDI – 22.4%, and that of the transient form 16.4% by discharge. Cushing’s disease, secondary adrenal insufficiency, microadenoma, MRI tumor’s volume <0,75 cm3 and surgery pituitary injury increase the odds of postoperative CDI, whereas acromegaly does decrease these odds.