Corticotroph deficiency.

Corticotroph deficiency usually results from exogenous glucocorticoid therapy or, more rarely, from hypothalamopituitary damages. Its diagnostic may be difficult, especially when the deficit in ACTH secretion is partial. Stimulation tests are then necessary to investigate the integrity of the hypothalamopituitary-adrenal axis. The insulin tolerance test has become the gold standard, but its utilization is limited by several contra-indications. The metyrapone and cosyntropin tests represent currently used alternatives but their sensitivity is not optimal. Measurement of basal plasma dehydroepiandrosterone sulfate may allow excluding corticotroph deficiency when normal. Finally, cortisol replacement in patients with corticotropic deficiency is based on hydrocortisone administration. However, the dose regimens employed in clinical practice do not allow mimicking the nycthemeral rhythm of cortisol secretion and are still disputed.