Endocrine Abstracts

Objectives

To assess diagnostic and prognostic markers of permanent and transient postoperative diabetes insipidus.

Patients and methods

The study included 152 patients undergone endoscopic endonasal transsphenoidal surgery aged from 18 to 65 years with median 40 [31; 52] years. Seventy three patients had Cushing disease, 66 – acromegaly, 4 – prolactinoma, 9 – hormonally inactive adenoma, 1 – Nelson syndrome, 1 – TSH-oma. Patients were monitored for clinical presentation, fluid balance, serum electrolytes, plasma and urine osmolality, copeptin level.

Results

By the end of follow-up period, permanent DI (pDI) has developed in 15 patients (15.5%), transient (tDI) – in 34 (35.1%), 47 patients did not have any disturbances (48.5%, ND) and 1 patient (1%) had SIADH. The onset was seen on the 5th median day [1; 9.5] after surgery for the pDI and on the 1^th median day [1; 4.5] for tDI; median for tDI’s duration was 30 days [1.5; 195]. Thirst and dry mouth were significantly more frequent in patients with pDI and tDI in comparison with patients without disturbances (OR 61.9 (10.1; 382.2), OR 25.3 (5.3; 121.5), P < 0.001; OR 22.0 (4.6; 104.8), OR 30.7 (7.8; 121), P < 0.001), just like water intake and daily urine were increased (P = 0.003, р=0.009 and P = 0.002, р=0.007, respectively). When assessing the blood osmolality level, no significant differences were found, however, the blood sodium level was significantly higher in patients with tDI compared to patients without disorders (145_pDI [142; 148], 146_tDI [144; 150], 144_ND [141; 147] – P = 0.008). In patients with pDI and tDI the indices of urine osmolality (0.296 [0.163; 0.36]_pDI, 0.282 [0.163; 0.36]_tDI, 0.652 [0.465; 0.929]_ND) and urine specific gravity (1.002 [1.0; 1.01]_pDI, 1.003 [1.001; 1.008]_tDI, 1.01 [1.005; 1.02]_ND) were significantly lower compared to patients without disturbances (P = 0.015, P = 0.001; P < 0.001, respectively) and sodium urine indices were significantly higher (50 [28; 74]_pDI, 56 [33; 73]_tDI, 109 [72; 127]_ND – P = 0.005_{pDI vs ND}, P = 0.001_{tDI vs ND}). When assessing the copeptin level, there were no significant differences between pre- and postoperative levels, but patients with a pDI had a sharp decrease in its level (median 10.1 [8.3;11] pmol/l before and 5.1 [4.9;6.2] after the intervention).

Conclusions

Clinical presentation, fluid balance, serum electrolytes, plasma and urine osmolality do not represent reliable diagnostic or prognostic markers of postoperative DI and its outcomes, but copeptin levels are a promising marker for further study.