Endocrine Abstracts

Objective: The origin of idiopathic isolated secondary adrenal insufficiency (IISAI) is uncertain, however autoimmunity seems to be the most probable cause. Within last eight years the initial number of about 100 such cases, increased in our registry by 250%. We searched for features of autoimmune diseases in our group of patients to prove autoimmune etiology in a majority of these patients.

Materials and methods: The material consisted of 260 patients with IISAI (female/male ratio 10.8, age 17–78 years). The diagnosis was based on clinical characteristics and hormonal (especially cortisol and ACTH) examinations, including ^1-24ACTH stimulating test. Methods: clinical examination, hormonal investigations (TSH, LH, FSH, PRL, fT₄), immunological studies (routine antithyroid autoantibodies + pituitary autoantibodies by an immunoblotting assay with human pituitary cytosol as autoantigen, in 65 patients), imaging methods (MRI of the pituitary – in a part of patients).

Results: Autoimmune disorders were diagnosed in 181 patients (70%), the most frequently thyroid diseases (especially hypothyroidism), vitiligo and premature ovarian failure. The thyroid autoantibodies were detected in 65% of the patients, while pituitary autoantibodies in 34% of the patients under study (immunoreactivity to a 49-kDa and to a novel 36-kDa pituitary autoantigen). Partially empty sella was the most frequent finding in MRI.

Conclusions: 1/ The incidence of the diagnosed idiopathic isolated secondary adrenal insufficiency is growing in last years, probably mainly due to a better detectability of disease. 2/ Association of autoimmune disorders with IISAI in 70% of the patients suggests autoimmune origin of pituitary disease, confirmed by the presence of pituitary autoantibodies in 34% of the patients under study.