Endocrine Abstracts

Introduction: Isolated corticotropic insufficiency of hypophysis with consecutive secondary adrenal insufficiency is a very rare disease. Literature notes difficulties in proper recognition and necessity of differential diagnosis, including among others chronic fatigue syndrome. In recent years, in Poland we observe more and more frequently setting this diagnosis – only on the basis of low ACTH an cortisol concentrations, despite of proper stimulation with 250 μg^1-24ACTH. As a result patients are treated with glucocorticoids, which, even in substitution doses increase risk of metabolic syndrome development.

Aim of the study: Our aim was to validate a diagnosis of secondary adrenal insufficiency in patient on prolonged treatment with Hydrocortisone.

Method: In 77 consecutive patients with Hydrocortisone treatment (6–24 months) referred to Clinic with diagnosis of secondary adrenal insufficiency (despite of proper stimulation with 250 μg 1-24 ACTH.), the 1mcg ^1-24ACTH stimulation (proper cortisol concentration >18 μg/dl) then the Metyrapone tests (proper deoxycortisol concentration >7.5 μg/dl) were performed. Tests were done after 2-days cessation in Hydrocortisone medication.

Results: Only in 13 patients (17%) low-dose ACTH test confirmed diagnosis of adrenal insufficiency, and in 10 of them also after-metyrapone deoxycortisol concentrations were too low. In 22 (28%) persons with proper stimulation after 1 and 250 μg ^1-24ACTH insufficient deoxycortisol increase after Metyrapone was stated. In the others 42 (55%) patients results of the both test were correct. In this group we were able to successfully stop Hydrocortisone treatment.

Conclusions: 1. In significant percentage of the cases recognized as secondary adrenal insufficiency only on the basis of random cortisol and ACTH measurements the diagnosis can be false-positive.

2. In patients with isolated corticotropin deficiency classic stimulation test with ^1-24 ACTH can give false-negative results and should be followed by low dose ^1-24ACTH test and Metyrapone test.