Endocrine Abstracts

The course and predictors of postoperative diabetes insipidus.

Objectives: To evaluate the course and predictors of permanent and transient postoperative diabetes insipidus (DI).

Patients and Methods: The study included 152 patients undergoing endoscopic endonasal transsphenoidal surgery aged from 18 to 65 years with median 40. 73 patients had Cushing disease, 66 – acromegaly, 4 – prolactinoma, 9 – hormonally inactive adenoma, 1 – Nelson syndrome, 1 – TSH-oma. Patients were monitored for hormones, serum electrolytes, plasma and urine osmolality. The follow-up period extended over 6 years for 97 patients and 55 patients (36%) had been lost to follow-up.

Results: In 34 patients (22.4%) postoperative DI was diagnosed by discharge, among them in 16 patients disturbances later became self-limited. Self-limited disturbances occurred in 25 patients (16.4%) when discharged, among them, permanent DI occurred in 3 patients during follow-up. 91 patients did not have any disturbances when discharged but permanent DI occurred in 1 patient and transient – in 8 patients during follow-up. By the end of follow-up period, permanent DI has developed in 15 patients (15.5%), transient – in 34 (35.1%). The onset was seen on the median 5th day [1; 9.5] after surgery for the permanent DI and on the 1th median day [1; 4.5] for transient; median for transient DI’s duration was 30 days [1.5; 195]. When assessing the level of osmolality and sodium, the indice of serum sodium in patients with a transient DI was significantly higher in comparison with patients without disturbances. In patients with a constant and transient DI the indices of urine osmolality and urine specific gravity were significantly lower compared to patients without disorders and sodium urine indices were significantly higher. The transient DI occurred more often in patients with corticotropinomas in comparison with other pituitary adenomas (OR 6.1 (2.3;16.1)) and in patients with microadenomas (ОR 5.3 (2.0;14.2)). Adrenal insufficiency increased risk of transient DI development (ОR 6.8 (2.6;18.3)) and secondary hypothyroidism – of permanent DI (ОR 9. 8 (2.1;46.6)) comparing to patients without hypopituitarism. Pituitary excision increased risk of permanent DI development as well (ОR 4.9 (1.3;17.6)).

Conclusions: The diagnosis of permanent or transient postoperative DI should be specified after a long-term follow-up. The onset of postoperative DI arises on the 1–5 day after surgery and rapidity of recovery varies wildly. Cushing disease, pituitary microadenomas and adrenal insufficiency can be considered as predictors of transient DI, secondary hypothyroidism and pituitary excision can be considered as predictors of the permanent postoperative DI.