Desmopressin is a safe and effective secretagogue to replace corticotropin-releasing hormone in petrosal sinus sampling.

PURPOSE: Bilateral inferior petrosal sinus sampling (BIPSS) with corticotropin-releasing hormone (CRH) was the gold standard for distinguishing Cushing disease (CD) from ectopic ACTH secretion (EAS). CRH, however, is no longer available.

OBJECTIVE

To assess the reliability of BIPSS with desmopressin to differentiate CD from EAS.

METHODS

A retrospective study included patients who underwent BIPSS with desmopressin for ACTH-dependent hypercortisolism, with the whole diagnostic procedure in a single center.

RESULTS

Fifty-eight patients with confirmed etiological diagnosis were included: 51 CD, 7 EAS. Forty-three CD patients (84.3%) had post-stimulation ratio ≥2 before stimulation and 6 of the other 8 (75%) had a ratio ≥3. All EAS patients were correctly diagnosed before and after stimulation. Sensitivity was 84.3% before stimulation and 92.2% combining pre- and post-stimulation results; specificity reached 100%. A ROC curve established optimal thresholds at 1.4 before stimulation and 1.7 after.

CONCLUSION

Desmopressin is a good substitute for CRH, correcting diagnosis compared to baseline BIPSS in 12% of cases.