The impossibility of predicting the development of hyponatremia in patients after transnasal adenomectomy

BACKGROUND : Hyponatremia is one of the most common and potentially dangerous complications following transnasal adenomectomy, making its timely detection and prevention critically important for improving treatment outcomes. Developing reliable models for predicting hyponatremia could reduce the risk of complications and enhance the quality of medical care for patients with pituitary adenomas. AIM : To analyze preoperative and postoperative parameters of patients to develop a prognostic model for hyponatremia development after transnasal adenomectomy. MATERIALS AND METHODS : A total of 122 patients were included in the analysis, of whom 38 (31%) were men. The patients were divided into two groups: those who developed hyponatremia by the 7th postoperative day and those who did not. The groups were comparable in terms of gender (p=0.425) and age (53 [34; 62] years vs. 44.5 [36; 56] years, p=0.172). A comparison of the groups was conducted across 42 parameters, including hormonal levels (ACTH, cortisol, TSH, free T4), the presence of cardiovascular diseases, carbohydrate metabolism disorders, and hypogonadism, the medication therapy administered, as well as tumor characteristics based on MRI data and surgical protocol details. RESULTS : No differences were found between the groups for any parameter (p>0.001). The groups were subsequently compared by laboratory parameters relative to reference ranges (TSH/ACTH/cortisol/free T4 above, below, or within the reference interval), tumor characteristics (e.g., color, consistency, position relative to the pituitary gland), and tumor morphology. No significant differences were identified for any of the parameters analyzed (all p>0.001). Thus, the groups with and without hyponatremia on the 7th postoperative day did not differ statistically, making it impossible to construct a prognostic mathematical model for this complication. CONCLUSION: The inability to predict postoperative hyponatremia based on preoperative parameters or surgical characteristics underscores the necessity of monitoring blood sodium levels until 10–14 days after transnasal adenomectomy.