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Updated: Sep 8, 2026

Endoscopic Endonasal Trans-sphenoidal Approach: Minimally Invasive Surgery for Pituitary Adenomas
Published on: January 17, 2018
[Fluctuating hyponatremia following transsphenoidal surgery ‒ "The challenge of correcting without going too far"]
Elena Vera Tuñón1, Luis Casamayor Escrivá1
1Servicio de Endocrinología y Nutrición. Hospital Universitario de Cuenca.
Introduction:
sodium disorders following pituitary represent one of the most common complications. Differential diagnosis between syndrome of inappropriate antidiuretic hormone secretion (SIADH) and a triphasic response is critical to avoid overcorrection.
Case Report:
we report a case of a 58-year-old male who underwent surgery for a pituitary macroadenoma and developed a triphasic response: initial polyuria, followed by transient SIADH. Due to a suboptimal response to fluid restriction and the risk of transitioning to a new polyuric phase, oral urea (30 g/day) was started. Gradual and safe sodium correction was achieved (128 to 132 mmol/l in 36 h), allowing early detection of the final shift back to diabetes insipidus without exceeding safety limits.
Discussion:
all in all, oral urea is an effective alternative for postoperative SIADH, providing more predictable and reversible osmotic control in scenarios of fluctuating natremia.
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