Endocrine Abstracts

Introduction: Effective surgical treatment of Cushing’s disease (CD) is associated with a rapid decrease in the serum cortisol concentration, which requires the introduction of the hydrocortisone replacement treatment. However, the time of restoration of adrenal function is difficult to predict. The aim of the study was to evaluate the dynamics of serum cortisol concentrations after successful transsphenoidal surgery and to determine the time to restore the function of the adrenal cortex.

Methods: The study included 23 consecutive patients (21 females; age: 25.6±8.0) with CD operated on by the same neurosurgeon. The remission was based on standard hormonal criteria. Serum cortisol was determined on the 1st postoperative day and then after 6 weeks, 3, 6, 12 and 18 months. Assays were carried out 48 h after hydrocortisone withdrawal. We considered the lower limit of referral range for cortisol (5.0 μg/dl) as the threshold of adrenal function recovery.

Results: In all cured patients serum cortisol levels on the 1st postoperative day was ≤2.5 μg/dl (median: 1.36 μg/dl). Median serum cortisol after 6 weeks and 3, 6, 12 and 18 months were: 1.0, 2.85, 2.97, 6.0, 10.2 μg/dl respectively. In none of the patients did we observed the return of adrenal function within 6 weeks of surgery. In four patients (17.4%) the adrenal function return was confirmed 3 months after the surgery, in four patients (17.4%) after 6 months, in five patients (21.7%) after 12 months. For the next seven patients (30.4%) return of adrenal function was confirmed after 18 months of follow-up. For the remaining three patients (13%) the serum cortisol concentration was still below 5.0 μg/dl.

Summary: In most cases, the return of adrenal cortex function is expected no earlier than 3 months following the successful surgery for CD. After 18 months of follow-up in more than 90% of the cases one should expect normal function of pituitary–adrenal axis.