ECE2022 Poster Presentations Adrenal and Cardiovascular Endocrinology (87 abstracts)
1Chru Strasbourg, Endocrinology, France; 2Chru Strasbourg, Hormonology Laboratory, France; 3CHRU Strasbourg, Endocrine Surgery, France; 4CHRU Strasbourg, Neurosurgery, France
Cushings syndrome (CS) is a rare and complex condition. Once the diagnosis of CS is confirmed, repetitive morning ACTH measurement is indicated to assess whether CS is ACTH dependent or independent. ACTH under 2,2 pmol/l characterises ACTH-independent CS and above 4,4 pmol/l ACTH-dependent CS. Some groups recommend midnight ACTH measurement rather than the morning. The purpose of our work was to evaluate 12PM ACTH vs 8AM ACTH measurement in the etiological diagnostic of CS, based on 42 patients with CS (Cushings disease, adrenal adenomas and adrenal carcinomas histologically proven) between 2004 and 2021. In Cushings disease (n=12), patients are correctly categorised ACTH-dependent whether ACTH is measured at 8AM (92%) or at 12PM (93%) (P=0,6). In adrenal carcinomas (n=6), patients are correctly categorised ACTH-independent whether ACTH is measured at 8AM (100%) or at 12PM (100%). In adrenal adenomas (n=24), patients are more accurately classified ACTH-independent when ACTH is measured at 12PM (96%) rather than 8AM (58%) (P=0,003). In the non-classified cases, the classification is corrected when both ACTH 12AM and 8Pm are performed. We observed that the particular interest of a 12AM dosage was observed in patients with milder hypercortisolism (defined as serum cortisol at 8 am under 138 nmol/l after dexamethasone 1 mg (overnight) suppression test). The main limits of our study are a small patients sample (histology needed), a retrospective data collection, and a possible measurement bias for ACTH due to the use of 3 different kit assays. Possible inclusion of subclinical CS cannot be ruled out. To our knowledge, no other study has compared 8AM and 12PM ACTH in the etiological diagnosis of CS. In summary, assessing the cause of CS by 8AM ACTH measurement seems appropriate in first line. Additional midnight ACTH may contribute to the etiological diagnosis in mild CS ACTH independent but requires patients night hospitalisation.