Isolated hyponatremia after transsphenoidal pituitary surgery

Area of Science:

• Endocrinology
• Neurosurgery
• Nephrology

Background:

• Cushing's disease is a complex endocrine disorder often treated with transsphenoidal surgery (TS).
• Postoperative fluid and sodium imbalances, particularly hyponatremia, are potential complications following TS.
• Understanding the incidence and contributing factors of hyponatremia is crucial for patient management.

Purpose of the Study:

• To investigate the incidence, timing, and potential associated factors of isolated hyponatremia after transsphenoidal surgery for Cushing's disease.
• To identify patient characteristics or surgical factors linked to the development of hyponatremia.
• To evaluate the clinical course and outcomes of patients experiencing hyponatremia post-TS.

Main Methods:

• Retrospective analysis of 58 patients undergoing TS for Cushing's disease over one year.
• Exclusion of patients with postoperative diabetes insipidus or volume depletion, focusing on 52 patients.
• Evaluation of plasma sodium levels, onset and duration of hyponatremia, and clinical symptoms.

Main Results:

• Isolated hyponatremia occurred in 21% of patients, with symptomatic hyponatremia (≤125 mmol/L) in 7%.
• Hyponatremia developed early postoperatively, progressing over 7 days, with maximum antidiuresis on day 7.
• Patients with a history of estrogenic milieu and posterior pituitary trauma had lower nadir plasma sodium levels.

Conclusions:

• Hyponatremia is a significant complication after TS for Cushing's disease, requiring careful monitoring.
• Unregulated vasopressin release may contribute to hyponatremia, though cortisol levels and adenoma size were not differentiating factors.
• Fluid restriction and active monitoring are effective in preventing severe morbidity and mortality in affected patients.