Inadequate Cortisol Response to the Tetracosactide (Synacthen®) Test in Non-Classic Congenital Adrenal Hyperplasia: An Exception to the Rule?

Aims: To describe cortisol response to tetracosactide and to review the literature on adrenal function in non-classic congenital adrenal hyperplasia (NCCAH) patients. Methods: We compared cortisol responses to tetracosactide (250 mu g) between NCCAH patients and a comparison group (CG) of patients with premature pubarche and normal tetracosactide test. An adequate cortisol response was defined as a peak >= 18 mu g/dl. Results: We included 35 NCCAH patients (26 girls, 9 boys), whose mean age at testing was 7.0 years (0.8-15.6), and 47 patients in the CG (39 girls, 8 boys), whose mean age was 7.2 years (0.5-9.9). Baseline cortisol was significantly higher in the NCCAH group than in the CG [12.9 (4.3-22.2) vs. 9.7 (4.2-16.2) mu g/dl, respectively; p = 0.0006]. NCCAH patients had lower cortisol peak response compared to the CG [18.2 (6.3-40) vs. 24.9 (12-30.3) mu g/dl, respectively; p < 0.0001]. Peak cortisol was <18 mu g/dl in 21/35 (60%) NCCAH patients versus 1/47 (2.1%) in the CG. No NCCAH patients had acute adrenal insufficiency, but 2 reported severe fatigue that improved with hydrocortisone. Conclusions: The cortisol response to tetracosactide was inadequate (<18 mu g/dl) in 60% of patients with NCCAH. Hydrocortisone therapy may deserve consideration when major stress (surgery, trauma, childbirth) or objectively documented fatigue occurs in NCCAH patients with inadequate cortisol response. (C) 2015 S. Karger AG, Basel