Indications
Differentiate between Cushing’s disease and pseudocushing’s.
Procedure
Measure plasma ACTH at baseline, 10 min, 20 min, and 30 min after administration of ddAVP 10 μg intravenously.
Interpretation
ACTH increase over baseline by ≥ 6 pmol/L after ddAVP indicates Cushing’s disease (Sn 81·5%, Sp 90%). [Giraldi 2007]
Caveats
The utility of the test has not been validated in a large population of patients with all causes of Cushing’s syndrome. [Nieman 2008]
References
- Pecori Giraldi F, Pivonello R, Ambrogio AG, De Martino MC, De Martin M, Scacchi M, Colao A, Toja PM, Lombardi G, Cavagnini F. The dexamethasone-suppressed corticotropin-releasing hormone stimulation test and the desmopressin test to distinguish Cushing’s syndrome from pseudo-Cushing’s states. Clin Endocrinol (Oxf). 2007 Feb;66(2):251-7.
- Lynnette K. Nieman, Beverly M. K. Biller, James W. Findling, John Newell-Price, Martin O. Savage, Paul M. Stewart, Victor M. Montori. The Diagnosis of Cushing’s Syndrome: An Endocrine Society Clinical Practice Guideline. JCEM, Volume 93, Issue 5, 1 May 2008, Pages 1526–1540.
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