How should we interrogate the hypothalamic-pituitary-adrenal axis in patients with suspected hypopituitarism?
Hypopituitarism is deficiency of one or more pituitary hormones, of which adrenocorticotrophic hormone (ACTH) deficiency is the most serious and potentially life-threatening. It may occur in isolation or, more commonly as part of more widespread pituitary failure. Diagnosis requires demonstration of subnormal cortisol rise in response to stimulation with hypoglycemia, glucagon, ACTH(1-24) or in the setting of acute illness. The choice of diagnostic test should be individualised for the patient and clinical scenario. A random cortisol and ACTH level may be adequate in making a diagnosis in an acutely ill patient with a suspected adrenal crisis e.g. pituitary apoplexy. Often however, dynamic assessment of cortisol reserve is needed. The cortisol response is both stimulus and assay- dependent and normative values should be derived locally. Results must be interpreted within clinical context and with understanding of potential pitfalls of the test used.
Division of Endocrinology, Beaumont Hospital, Dublin, Ireland.
Aoife
A
Garrahy
Division of Endocrinology, Beaumont Hospital, Dublin, Ireland. amaragha@beaumont.ie.|RCSI Medical School, Dublin, Ireland. amaragha@beaumont.ie.
Amar
A
Agha
D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000172:deficiency; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007003:Hypoglycemia / Q000378:metabolism / Q000503:physiopathology; D007018:Hypopituitarism / Q000175:diagnosis* / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism / Q000503:physiopathology*; D010913:Pituitary-Adrenal System / Q000378:metabolism / Q000503:physiopathology*; D013312:Stress, Physiological
D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone