Endocrine Abstracts

Objective: In subclinical Cushing’s syndrome (SC), it is assumed that glucocorticoid production is insufficient to cause a clinically recognizable syndrome. Differences in hormonal levels or recovery time of the hypothalamic–pituitary–adrenocortical (HPA) axis after adrenalectomy between patients with overt Cushing’s syndrome (OC) and SC remain unknown.

Design and patients: Thirty seven patients (ten were OC and 27 were SC) with adrenal Cushing’s syndrome who underwent adrenalectomy from 2004 to 2014 were reviewed retrospectively. Patients were treated with glucocorticoid after adrenalectomy, and adrenal function was evaluated every 1–6 months with a rapid ACTH stimulation test.

Results: Patients with SC were older than patients with OC. Levels of basal 24-h urine free cortisol (24hUFC), serum cortisol after an overnight dexamethasone suppression test (DST), and serum cortisol and 24hUFC after low- and high-dose DST were all significantly lower in patients with SC compared with OC (P<0.01). The probability of recovering adrenal function differed significantly between patients with OC and SC (P=0.001), with significant correlations with the degree of preoperative cortisol excess. Patients with OC required a longer duration of glucocorticoid replacement to recover a normal ACTH stimulation test compared with patients with SC (median 13.5 vs 4 months, P <0.001), and seven patients with SC (26%) did not receive steroid replacement after adrenalectomy.

Conclusions: The HPA axis recovery time after adrenalectomy in patients with SC is rapid (within several months) and is dependent on the degree of cortisol excess. Routine postoperative glucocorticoid replacement is not necessary in some patients with SC.