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.

1. Pigarova EA, Dzeranova LK, Zhukov AYu, Grigoriev AYu, Azizyan VN, Ivaschenko OV, Dedov II. Electrolyte disorders after endoscopic transnasal neurosurgical interventions. Endocrine Surgery. 2019;13(1):42-55. (In Russ.) doi: https://doi.org/10.14341/serg10205

2. Badmaeva IN, Astafyeva LI, Kalinin PL, Kadashev BA, Kutin MA. Central diabetes insipidus after resection of sellarsuprasellar tumors: prevalence and predictors of manifestation. Burdenko’s Journal of Neurosurgery. 2021;85(6):111 118. (In Russ.) doi: https://doi.org/10.17116/neiro202185051111

3. Patel KS, Shu Chen J, Yuan F, et al. Prediction of postoperative delayed hyponatremia after endoscopic transsphenoidal surgery. Clin Neurol Neurosurg. 2019;182:87-91. doi: https://doi.org/10.1016/j.clineuro.2019.05.007

4. Adrogué HJ, Tucker BM, Madias NE. Diagnosis and Management of Hyponatremia: A Review. JAMA. 2022. doi: https://doi.org/10.1001/jama.2022.11176

5. Peri A. Morbidity and Mortality of Hyponatremia. In: Frontiers of Hormone Research. ; 2019:36-48. doi: https://doi.org/10.1159/000493235

6. Patel KS, Shu Chen J, Yuan F, et al. Prediction of postoperative delayed hyponatremia after endoscopic transsphenoidal surgery. Clin Neurol Neurosurg. 2019. doi: https://doi.org/10.1016/j.clineuro.2019.05.007

7. Rajaratnam S, Jeyaseelan L, Rajshekhar V. Delayed Hyponatremia Following Surgery for Pituitary Adenomas: An Under-recognized Complication. Neurol India. 2020. doi: https://doi.org/10.4103/0028-3886.280637

8. Kristof RA, Rother M, Neuloh G, Klingmüller D. Incidence, clinical manifestations, and course of water and electrolyte metabolism disturbances following transsphenoidal pituitary adenoma surgery: A prospective observational study: Clinical article. J Neurosurg. 2009. doi: https://doi.org/10.3171/2008.9.JNS08191

9. Hong YG, Kim SH, Kim EH. Delayed Hyponatremia after Transsphenoidal Surgery for Pituitary Adenomas: A Single Institutional Experience. Brain Tumor Res Treat. 2021;9(1):16–20

10. Taylor SL, Tyrrell JB, Wilson CB. Delayed Onset of Hyponatremia after Transsphenoidal Surgery for Pituitary Adenomas. Neurosurgery. 1995;37(4):649-654. doi: https://doi.org/10.1227/00006123-199510000-00007

11. Hussein Z, et al. The management and outcome of hyponatraemia following transsphenoidal surgery: a retrospective observational study. Acta Neurochir. 2022;164(4):1135–1144

12. Barber SM, Liebelt BD, Baskin DS. Incidence, Etiology and Outcomes of Hyponatremia after Transsphenoidal Surgery: Experience with 344 Consecutive Patients at a Single Tertiary Center. J Clin Med. 2014;3(4):1199-219. doi: https://doi.org/10.3390/jcm3041199

13. Constanthin PE, Isidor N, de Seigneux S, Momjian S. Increased oxytocin release precedes hyponatremia after pituitary surgery. Pituitary. 2021;24(3):420-428. doi: https://doi.org/10.1007/s11102-020-01121-4

14. Lin K, et al. Predictive factors for delayed hyponatremia after transsphenoidal surgery in patients with pituitary adenomas. 2022

15. Olson BR, Gumowski J, Rubino D, Oldfield EH. Pathophysiology of hyponatremia after transsphenoidal pituitary surgery. J Neurosurg. 1997;87(4):499-507. doi: https://doi.org/10.3171/jns.1997.87.4.0499

16. T Sane, K Rantakari, A Poranen, R Tähtelä, M Välimäki, R Pelkonen. Hyponatremia after transsphenoidal surgery for pituitary tumors. The Journal of Clinical Endocrinology & Metabolism. 1994; 79(5):1395–1398. doi: https://doi.org/10.1210/jcem.79.5.7962334

17. Kelly DF, Laws ER, Fossett D. Delayed hyponatremia after transsphenoidal surgery for pituitary adenoma. Report of nine cases. J Neurosurg. 1995;83(2):363–367

18. Hong YG, Kim SH, Kim EH. Delayed Hyponatremia after Transsphenoidal Surgery for Pituitary Adenomas: A Single Institutional Experience. Brain Tumor Res Treat. 2021;9(1):16-20. doi: https://doi.org/10.14791/btrt.2021.9.e5

19. Prete A, Corsello SM, Salvatori R. Current best practice in the management of patients after pituitary surgery. Ther Adv Endocrinol Metab. 2017;8(3):33–48

20. Zada G, Liu CY, Fishback D, Singer PA, Weiss MH. Recognition and management of delayed hyponatremia following transsphenoidal pituitary surgery. J Neurosurg. 2007;106(1):66-71. doi: https://doi.org/10.3171/jns.2007.106.1.66