Can basal cortisol measurement be an alternative to the insulin tolerance test in the assessment of the hypothalamic–pituitary–adrenal axis before and after pituitary surgery?

Abstract

Background: The aims of this study were to evaluate the validity of preoperative basal serum cortisol levels measured in predicting preoperative adrenal insufficiency and also the validity of basal serum cortisol levels and early postoperative insulin tolerance test (ITT) in predicting postoperative adrenal insufficiency. Methods: The study was prospectively designed and included 64 patients who underwent pituitary surgery for conditions other than Cushing's disease. An ITT was performed preoperatively, on the 6th postoperative day and at the 1st postoperative month. Basal serum cortisol levels were measured on the 2nd, 3rd, 4th, 5th, and 6th postoperative days. Results: Patients with a preoperative basal cortisol level of !165 nmol/l (6 mg/dl) showed insufficient cortisol response and those with levels higher than 500 nmol/l (18 mg/dl) had sufficient cortisol response to the preoperative ITT. The positive predictive value of the ITT performed on the 6th postoperative day was 69.7%, and the negative predictive value in predicting adrenal insufficiency at the 1st postoperative month was 58%. Patients were considered to have an insufficient cortisol response to ITT at the 1st postoperative month if their basal cortisol levels were !193 nmol/l (7 mg/dl) or 220 nmol/l (8 mg/dl) or 193 nmol/l (7 mg/dl) or 165 nmol/l (6 mg/dl) or 83 nmol/l (3 mg/dl) on the 2nd-6th postoperative days respectively. Conclusion: Serum basal cortisol levels may be used as the first-line test in the assessment of the hypothalamic-pituitary-adrenal axis both preoperatively and postoperatively. Dynamic testing should be limited to the patients with indeterminate basal cortisol levels.

Pituitary apoplexy: re-evaluation of risk factors for bleeding into pituitary adenomas and impact on outcome

“…Moreover, concerning the endocrine status of the patients, we had only limited data on insulin hypoglycaemia stress tests, considered as gold standard for the determination of secondary adrenal failure. However, serum basal cortisol levels in the early morning may be used as first-line test in the assessment of the hypothalamicpituitary-adrenal axis both preoperatively and postoperatively, as well (24).…”

The Role of Morning Basal Serum Cortisol in Assessment of Hypothalamic Pituitary-Adrenal Axis

“…Studies have looked at the role of morning basal cortisol drawn between 0800-0900h as a screening test that typically re ects the highest physiologic levels attained throughout the day, usually peaking 30-45 minutes a er awakening [5]. ese studies have generally focused on speci c patient populations of pre- [6,7] and post-pituitary surgeries [8,9] and consequently proposed variable lower and upper serum basal cortisol levels that would obviate the need for patients to undergo further dynamic testing. [8,[10][11][12][13].…”

Increased Cortisol Levels in Depression: A Comparative Study Evaluating the Correlation of Hypercortisolemia with Prosocial Coping Mechanisms

“…In the current research the morning serum cortisol was measured, due to lack of availability of alternative methods. In the last years cortisol level from saliva was used to determine the cortisol awaking response (CAR), but the use of morning basal serum cortisol levels as an alternative to dynamic testing for assessment of hypothalamic-pituitary-adrenal axis has previously been reported [ 23].Serum basal cortisol levels may be used as the first-line test in the assessment of thehypothalamic-pituitary-adrenal axis both preoperatively and postoperatively [24].…”