Sodium and water imbalance after sellar, suprasellar, and parasellar surgery

Objective: To report the frequency of sodium and water disturbances (SWDs) in patients undergoing sellar, suprasellar, and parasellar surgery (SSPS). Methods: We conducted a cross-sectional, retrospective study on 115 patients in the Aga Khan University Hospital after ethical approval. Patients were 16 years old or older undergoing pituitary or sellar surgeries. We collected data on basic sociodemographic characteristics and clinical indication for surgery. We noted laboratory values for serum electrolytes, plasma and urine osmolality, urine sodium, and 24-hour fluid balance from the immediate postoperative day until discharge and follow-up. We recorded medical management plans. We also recorded diabetes insipidus (DI), syndrome of inappropriate antidiuretic hormone (SIADH), cerebral salt wasting (CSW), triphasic response, and hyponatremia, according to the diagnostic definitions. Finally, we performed data analysis using Statistical Package for the Social Sciences, version 19.0. Results: Of 115 patients, there were 61.7% males, mean age 42.3 ± 13.86 years, 91.3% had pituitary adenoma (73.0% nonfunctioning), and 86.1% underwent transsphenoidal surgical approach. Transient DI occurred from days 1 to 6, peaking with 57.4% on day 2. Permanent DI and SIADH were rare. We did not note typical triphasic response or CSW in any of the patients. However, isolated hyponatremia occurred in 11%, and 20.9% had DI with hyponatremia. Conclusion: Transient DI is the most common postoperative SWD after SSPS. Hyponatremia occurred alone and following DI. This is the first study describing postoperative SWDs after different sellar surgeries in Pakistan.