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Medline ® Abstract for Reference 50

of 'Vasopressin and desmopressin stimulation test'

The role of desmopressin in bilateral and simultaneous inferior petrosal sinus sampling for differential diagnosis of ACTH-dependent Cushing's syndrome.
Machado MC, de Sa SV, Domenice S, Fragoso MC, Puglia P Jr, Pereira MA, de Mendonça BB, Salgado LR
Clin Endocrinol (Oxf). 2007;66(1):136.
OBJECTIVE: Bilateral inferior petrosal sinus sampling (BIPSS) with corticotrophin-releasing hormone (CRH) stimulation is currently the gold standard test for the differential diagnosis of ACTH-dependent Cushing's syndrome. Reports on the use of desmopressin in this approach are limited. The aim of this study was to evaluate the use of desmopressin during BIPSS in a cohort of patients with ACTH-dependent Cushing's syndrome.
DESIGN: A retrospective case-record study.
PATIENTS: Fifty-six patients with confirmed ACTH-dependent Cushing's syndrome underwent BIPSS with desmopressin stimulation when presenting negative pituitary tumour imaging.
MEASUREMENTS: Central to peripheral (CEN:PER) ACTH gradient, lateralization of the ACTH source and surgical tumour confirmation were evaluated.
RESULTS: A CEN:PER ACTH gradient was found in 40 patients under basal conditions (CEN:PER>or= 2) and in 47 patients after desmopressin stimulation (CEN:PER>or= 3). Ectopic ACTH-producing tumours (three lung carcinoid tumour, one thymus carcinoid tumour and one thymus hyperplasia) were confirmed in five out of nine patients without the CEN:PER ACTH gradient, and four cases were false negative for Cushing's disease. Lateralization (IPS:IPS>or= 1.4) was observed in 80.8% of patients under basal conditions (38/47) and in 97.8% after desmopressin (46/47), and it was surgically confirmed in 78.7%. There were no false-positive cases. Sensitivity and specificity were 92.1% and 100%, respectively.
CONCLUSIONS: Desmopressin improves the differential diagnosis of ACTH-dependent Cushing's syndrome by amplifying the CEN:PER and IPS:IPS ACTH gradients, and is therefore a useful ACTH secretagogue in BIPSS.
Division of Endocrinology and Metabolism, University of Sao Paulo School of Medicine, Sao Paulo, SP, Brazil.