Early Morning Cortisol Levels as Predictors of Short- and Long-Term Adrenal Function after Endonasal Transsphenoidal Surgery for Pituitary Adenomas and Rathke's Cleft Cysts

Introduction: Patients undergoing pituitary adenoma or Rathke's cleft cyst (RCC) removal are often administered perioperative glucocorticoids regardless of lesion size and preoperative ACTH/cortisol levels. To minimize unnecessary glucocorticoid therapy, we describe a protocol in which patients with normal preoperative serum cortisol and ACTH levels are given glucocorticoids only if postoperative day 1 or 2 (POD1 or POD2) cortisol levels fall below normal.

Methods: A total of 207 consecutive patients undergoing endonasal surgery for an adenoma or RCC were considered for study. Of these, 68 patients with preoperative adrenal insufficiency or Cushing's disease were excluded. Glucocorticoids were withheld unless POD1/POD2 morning cortisol values were below normal (≤4 μg/dL). Subsequent adrenal status was assessed through follow-up biochemical and clinical evaluations.

Results: The 139 patients included 119 with macroadenomas, 14 microadenomas and 6 RCCs (follow-up, 3–41 months; median, 10 months). Nine (6.5%) patients, all with macroadenomas (mean diameter 26 ± 10 mm) had low POD1/POD2 cortisol values and received glucocorticoids; of these, 5 were weaned off within 3–28 weeks of surgery. Overall, 12/139 (8.6%) patients were treated for early (n = 9) or delayed (n = 3) adrenal insufficiency, but only 5 (3.6%) remain on glucocorticoid replacement. No patients experienced an adrenal crisis.

Conclusion: In patients with normal preoperative cortisol levels undergoing endonasal removal of a pituitary adenoma or RCC, normal morning cortisol values on POD1/POD2 reliably predicts adequate and safe adrenal function in over 96% of patients. This simple protocol of withholding postoperative glucocorticoids avoids unnecessary steroid exposure and poses minimal risk to the well-informed, closely monitored patient.