Evaluation of the corticotrophin-releasing-hormone test and the high dose dexamethasone suppression test in ACTH dependent Cushing's syndrome: a 25-year prospective cohort study

Abstract Purpose The differential diagnosis of ACTH-dependent Cushing’s syndrome remains a challenge in clinical practice. The aim of the present study was to assess the diagnostic performance of pituitary dynamic enhanced MRI(dMRI), high-dose dexamethasone suppression test༈HDDST༉and combination of both tests in patients with ACTH-dependent Cushing’s syndrome. Methods 119 consecutive cases with surgery confirmed ACTH-dependent Cushing’s syndrome were enrolled: 101 patients with proven Cushing’s disease and 18 patients with proven ectopic ACTH syndrome. All patients underwent pituitary dMRI and HDDST. The sensitivity and the specificity of pituitary dMRI, HDDST, and combination of both tests were calculated. Results The sensitivity and specificity of the pituitary dMRI for the diagnosis of Cushing’s disease was 80.2% and 83.3% respectively, and the positive predictive value was 96.4%. The sensitivity and specificity of HDDST was 70.3% and 77.8%, and the positive predictive value was 94.7%. Regarding the combination of both tests, the combined criteria of a more than 50% suppression of serum cortisol in HDDST and a positive finding in pituitary dMRI had given a high specificity of 94.4% and a sensitivity of 59.4%. The combined criteria of a greater than 68% suppression in HDDST and/or a positive finding in pituitary dMRI, provide a sensitivity of 86.1% and a specificity of 83.3%. Conclusions Pituitary dMRI was superior to HDDST in the differential diagnosis of ACTH-dependent Cushing’s syndrome. HDDST was recommended to combined with pituitary dMRI in the diagnosis process because of the significantly increased specificity of the combination.

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Nocturnal high-dose dexamethasone suppression test in the aetiological diagnosis of Cushing's syndrome

Acta Endocrinologica ◽

10.1530/acta.0.1090158 ◽

1985 ◽

Vol 109 (2) ◽

pp. 158-162 ◽

Cited By ~ 27

Author(s):

O. D. Bruno ◽

Maria A. Rossi ◽

Liliana N. Contreras ◽

R. M. Gómez ◽

G. Galparsoro ◽

...

Keyword(s):

Cushing’S Syndrome ◽

Cushing's Syndrome ◽

Dexamethasone Suppression Test ◽

High Dose ◽

Ectopic Acth ◽

High Dose Dexamethasone ◽

Power Of The Test ◽

Suppression Test ◽

Aetiological Diagnosis ◽

Dexamethasone Suppression

Abstract. Seventeen patients with well-proven Cushing's syndrome (13 with Cushing's disease, 3 with adrenal tumour and 1 presenting ectopic ACTH syndrome caused by bronchial carcinoid) were investigated by using a single-dose 8 mg dexamethasone nocturnal test. The results obtained were compared with those of the classical 8 mg Liddle's test, metyrapone stimulation, plasma ACTH concentration and with the final diagnosis reached through surgery, pathologic anatomy, and/or clinical and biochemical follow-up of the patients after treatment. The diagnostic efficacy or the predictive power of the test (defined as the ratio between the number of cases in which the diagnosis was correctly predicted and the total number of cases), was at least 82.4% vs 84.6% for the classical 8 mg Liddle's test. This percentage increased to 94.1% when the results of repeated tests on three patients with conflicting data were included. It is concluded that the nocturnal high-dose dexamethasone suppression test is a valuable tool in the aetiological diagnosis of Cushing's syndrome.

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