Central diabetes insipidus after transnasal adenomectomy:trends in development and recovery, clinical and laboratory characteristics

Background: Currently, there is an increase in the incidence of chiasmosellar neoplasms and respective neurosurgical interventions. The postoperative period may be complicated by vasopressin synthesis and secretion disorders. Both the development and abortion of the fluid and electrolyte disorders can be delayed. Due to a tendency for an earlier discharge of the patients, a proportion of the disorders remain unaddressed. There is no data on the evolution and time to regress of transient abnormalities in the published studies with a long-term postoperative follow-up. Aim: To assess the incidence, evolution and regression trends, clinical and laboratory characteristic of postoperative central diabetes insipidus (CDI). Materials and methods: The single center retrospective comparative study included 150 patients who had undergone transnasal adenomectomy for Cushings disease, acromegaly, prolactinomas, and hormonally inactive pituitary adenomas. Clinical and laboratory assessments were performed pre- and postoperatively. In the event of CDI, treatment with desmopressin was administered. Ninety six (96) patients aged 20 to 65 years (median age 43 [35; 54] years) were followed for at least 60 months after the procedure. Results: Median time to the onset of permanent CDI (pCDI) was Day 5 [1; 9.5] after surgery, that of transient CDI (tCDI) Day 1 [1; 4.5] with its remission by Day 30 [1.5; 199]. The maximally delayed onset was on Day 86 for the pCDI and Day 61 for tCDI; that to the remission of tCDI, 738 days. At discharge from the hospital, postoperative CDI was present in 34/150 patients (23%; 95% CI 1730), and in 25/150 of the patients (16%; 95% CI 1224) the disorder resolved. At 5 to 7 years after surgery, the prevalence of pCDI was 16% (95% CI 1024), that of tCDI 35% (95% CI 2745), 49% (95% CI 3959) of the patients had no abnormalities (respective absolute patient numbers being 15, 34, and 47 of 96 followed for at least 60 months). At Days 1 to 7 after surgery, the patients with pCDI and tCDI had more frequent complaints of dry mouth and thirst than those without the disorder. These complaints were verified by higher 24-hour fluid intake and diuresis at the day of surgery and Days 5 to 7 thereafter, compared to those in the patients without the disorders. At Days 57 after surgery, urine sodium and urine specific gravity were significantly lower, as was urine osmolality at all postoperative stages, compared to those in the patients without the disorders. Conclusion: Within 2 years after transnasal adenomectomy, the incidence of postoperative CDI is gradually decreasing (from 23% to 16%). Due to potentially delayed manifestation of water and electrolyte imbalance, it is recommended that these parameters should be monitored at least for 2,5 months after the discharge from hospital. Due to potentially delayed remission (12 months and more), follow-up and monitoring for 1.5 years is reasonable, with periodic assessment of sodium levels, fluid intake and excretion, and attempts to withdraw desmopressin.