Is isolated secondary adrenal insufficiency more frequent than autoimmune Addisons disease?
A. Kasperlik-Zaluska1, B. Czarnocka1, W. Jeske1, L. Papierska1, A. Hulting2, S. Bensing2, P. Crock3 & O. Kampe4
Similarly as in autoimmune Addisons disease (AAD), diagnosed in about 80% of primary adrenal insufficiency, idiopathic isolated secondary adrenal insufficiency (ISAI) seems to have an autoimmune origin.
Within the last 35 years we have registered in our Department 325 patients with ISAI (F/M ratio 10.9) aged 1787 years. In comparison, we have in our registry 241 patients with AAD, collected within over 40 years. The diagnosis of ISAI was based on clinical examination and hormonal, immunological and imaging studies. The hormonal investigations: cortisol and plasma ACTH (circadian rhythm), TSH, LH, FSH, PRL, fT4, androgens, E2, testosterone, Synacthen-stimulation test, urinary excretion of cortisol. Immunological studies:antithyroid and pituitary autoantibodies with an immunoblotting assay (with human pituitary cytosol as an autoantigen in 65 patients. A corticotroph-specific transcription factor (Tpit) was investigated as a candidate autoantigen. MRI of the pituitary in a part of cases.
Results: In all ISAI patients basal cortisol and ACTH levels were found to be below the lower normal limit while Synacthen significantly stimulated cortisol secretion. Various autoimmune disorders were detected in 215 patients, the most frequently thyroid diseases (mainly hypothyroidism), vitiligo, premature ovarian failure, pernicious anemia and T1DM. The thyroid autoantibodies were found in 65%, while pituitary autoantibodies in 34% of patients under study. Tpit was identified as a minor antigen in 10.5% of of the investigated patients. Partially enpty sella was the most frequent imaging finding.
Conclusions: ISAI appeared to be more frequent than AAD. 2/ Association of various autoimmune disorders in 66% of ISAI patients suggests autoimmune origin of the idiopathic isolated secondary adrenal insufficiency.
Supported by a 501210723/09 & 50110811/11 CMKP Grant.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.