Bilateral inferior petrosal sinus sampling in the differential diagnosis of adrenocorticotropin-dependent Cushing's syndrome : A comparison with other diagnostic tests

• Published in: The journal of clinical endocrinology and metabolism Vol. 85; no. 4; pp. 1525 - 1532
• Main Authors: WIGGAM, M. I, HEANEY, A. P, MCILRATH, E. M, MCCANCE, D. R, SHERIDAN, B, HADDEN, D. R, ATKINSON, A. B
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Endocrine Society 01.04.2000
• Subjects: Adolescent; Adrenocorticotropic Hormone - blood; Adrenocorticotropic Hormone - secretion; Adult; Aged; Biological and medical sciences; Corticotropin-Releasing Hormone; Cushing Syndrome - diagnosis; Cushing Syndrome - physiopathology; Dexamethasone; Diagnosis, Differential; Female; Functional investigation of endocrine glands and genital system; Glucocorticoids; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Petrosal Sinus Sampling; Sensitivity and Specificity; Endocrinopathy; Performance evaluation; Human; Adrenal cortex diseases; Inferior petrosal sinus; Corticotropin releasing factor; Cushing syndrome; Hyperadrenocorticism; Differential diagnostic; Dexamethasone test; Adrenocorticotropic hormone; Adenohypophyseal hormone; Etiology; Adrenal gland diseases; Hormonal investigation
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.85.4.1525

To compare bilateral inferior petrosal sinus sampling (IPSS) with high dose dexamethasone (HDD) and CRH testing (using recently proposed stringent response criteria) in the differential diagnosis of ACTH-dependent Cushing's syndrome, we reviewed 53 consecutive cases. The main analysis was limited to 45 cases with confirmed diagnosis: 44 with pituitary dependency, proven by confirmatory histology and/or significant biochemical improvement after pituitary surgery, and 1 with ectopic ACTH syndrome. After HDD (2 mg every 6 h for 48 h), 21 of the 44 pituitary cases met the stringent more than 90% suppression criterion. Twenty-three of the 44 pituitary cases also underwent CRH testing; 16 of 23 met a stringent response criterion of a more than 50% serum cortisol rise. For HDD and CRH testing combined, 8 of 23 fulfilled both stringent criteria, 10 of 23 had discordant results, and 5 of 23 failed to fulfil either of the stringent criteria for pituitary dependency. IPSS was performed in all 44 of the proven pituitary cases; 36 had petrosal/peripheral ACTH ratios of 2.0 or more without CRH stimulation. Thus, in patients with proven pituitary disease, stringent response criteria to HDD and CRH testing were fulfilled by only 48% and 70%, respectively. IPSS, which gave direct evidence of pituitary ACTH secretion in 82% of the cases, is therefore considered necessary in a significant proportion of cases.