Endocrine Abstracts

Introduction: Assessment of adrenal insufficiency (AI) is done routinely through Synacthen test. However, the conventional high dose (250 μg) stimulation is supra-physiological, therefore 1 μg low dose test was developed.

Aim: to investigate the utility of the Low-dose test vs the High-dose test, in patients with suspected central AI, in a tertiary centre of endocrinology, in the National Institute of Endocrinology, Bucharest, Romania.

Material and methods: We performed a retrospective study spanning the period from 2019 to 2023. This study focused on patients presenting diverse disorders leading to central AI. The aetiology was: pituitary adenomas (n=35), basal or postsugery, adrenal Cushing after surgery (n=31), congenital hypopituitarism (n=11), patients previously on corticosteroids (n=10), after stopping the GC treatment and oncologic patients under immunotherapy (n=9). After basal sampling between 8-10 AM, a dose of synthetic ACTH (Synacthene) was injected iv, 250 μg for high dose and 1 μg for low dose test. Cortisol was sampled at 30 and 60 min.

Results: Among the participants (n=117), 36.8 % were male and 63.2 % were female. Complete recovery is considered if serum cortisol levels after stimulation rises over a minimum of 18 μg/dl (12-18 μg/dl is considered incomplete response, values lower than 12 μg/dl is considered diagnostic for AI). Out of the 117 patients 23 (31.9%) were found to have AI in Low-dose testing (cortisol 0’=6.78 mg/dl ± 4.2, T1=16.19 mg/dl ± 8.5, T2=16.09 ± 9.04) vs. 4 (cortisol 0’=11.92 mg/dl ± 6.19, T1=31.76 ± 12.45, T2=27.46 ± 13.07) (3.3%) in the High-dose test therefore, they required ongoing treatment. Subclinical AI with incomplete response was present in 14 patients, requiring treatment in stress conditions. Among all patients in the low-dose test 10 (13.9 %), respectively 16 (35.6%) in the high-dose test achieved normal adrenal function.

Conclusion: Low dose Synachtene revealed more cases of AI, who required substitution treatment. The findings highlight the need for further research to optimize treatment strategies and improve outcomes for individuals with central hypocorticism.