title: Pros and cons of dexamethasone suppression test for screening of subclinical Cushing's syndrome in patients with adrenal incidentalomas.
abstract: The results of dexamethasone suppression tests (DST) in the screening of subclinical hypercortisolism are not readily comparable. Aim of the present study was to review the effectiveness of overnight 1-mg DST and 8-mg DST to look for functional autonomy of clinically inapparent adrenal adenomas. Sixty-eight consecutive patients with clinically inapparent adrenal adenomas were enrolled. All patients underwent 1-mg DST. The 8-mg DST was performed in the 11 patients who had post 1-mg DST cortisol >138 nmol/l and in 11 patients who had post 1-mg DST cortisol between 50 and 138 nmol/l. The a priori probability to have autonomous cortisol secretion was defined by the presence of at least two alterations of the hypothalamic-pituitary-adrenal axis among reduced ACTH concentrations, elevated urinary free cortisol (UFC) or elevated midnight serum cortisol. Cortisol levels >138 nmol/l after the 1-mg DST increases the post-test probability of adrenal functional autonomy to 55%, whereas cortisol levels <50 nmol/l reduce the post-test probability to 8%. Cortisol levels recorded after the 8-mg DST were nonsignificantly lower than after the 1-mg DST and all the patients with cortisol >138 nmol/l after the 1-mg DST maintained cortisol above this cut-point. The 1-mg DST should be considered as the more effective test to detect autonomous cortisol secretion by a clinically inapparent adrenal adenoma when cortisol levels are >138 nmol/l, while cortisol levels <50 nmol/l reduce remarkably the post-test probability of this event. The 8-mg DST seems to replicate by large the results of the 1-mg DST.
authors.affiliation: Internal Medicine I-Endocrinology, Department of Clinical and Biological Sciences, A.O.U. San Luigi Gonzaga, University of Turin, A.S.O. San Luigi, Regione Gonzole 10, 10043 Orbassano, Italy. giuseppe.reimondo@unito.it
authors.forename: G
authors.initials: G
authors.lastname: Reimondo
authors.forename: B
authors.initials: B
authors.lastname: Allasino
authors.forename: S
authors.initials: S
authors.lastname: Bovio
authors.forename: L
authors.initials: L
authors.lastname: Saba
authors.forename: A
authors.initials: A
authors.lastname: Ardito
authors.forename: A
authors.initials: A
authors.lastname: Angeli
authors.forename: M
authors.initials: M
authors.lastname: Terzolo
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000150:complications / Q000175:diagnosis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058070:Asymptomatic Diseases; D000075202:Contraindications; D003480:Cushing Syndrome / Q000175:diagnosis* / Q000209:etiology*; D003907:Dexamethasone / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D010912:Pituitary-Adrenal Function Tests / Q000379:methods* / Q000592:standards; D010913:Pituitary-Adrenal System / Q000378:metabolism / Q000503:physiopathology; D012189:Retrospective Studies
chemical_list: D003907:Dexamethasone