Endocrine Abstracts

Background

Cushing syndrome (CS) is caused by prolonged exposure to elevated cortisol levels and it’s classified as either ACTH-dependent or ACTH independent CS. The most common form of endogenous ACTH CS is Cushing disease (CD); ACTH-independent CS is caused by various adrenal abnormalities. First-line therapy in CS is the resection of the underlying tumor in all cases. After surgical cure of CS, most patients develop transient secondary adrenal insufficiency (SAI) requiring postoperative glucocorticoid (GC) replacement. The aim of this study is to review the time to normalization of adrenal function after surgical cure of CS.

Patients and Methods

This study is based on the review of 34 patients cured by surgery, after being diagnosed either with CD (15) or ACTH-independent CS with overt CS (19) in our endocrinology department between 2010–2020. All patients were declared cured of CS with postoperative SAI. GC replacement was started for basal plasma cortisol < 5 mg/dl or a stimulated plasma cortisol < 20 mg/dl, using synthetic ACTH with follow-up at 3, 6, 9 months and 1 year or more in selected cases in order to see the duration of SAI.

Results

Data showed that they received GC replacement for a period of time that ranged from 4 to 27 months, 2 of them with permanent SAI. The decision of ceasing therapy was based on a stimulated cortisol value ≥ 20 mg/dl, without any evidence of SAI symptoms after that. Patients with CD required a longer period of substitution (a mean of 17.5 months) than patients with ACTH-independent CS (a mean of 13.3 months).

Conclusions

Successful surgery in CS leaves behind SAI, requiring a long term steroid substitution. The decision of whom to treat is based on many clinical and biochemical data, besides absolute cortisol values.