Endocrine Abstracts

Hypocorticotropism refers to ACTH insufficiency, which may be partial or complete, isolated or combined, genetic or acquired, pituitary or hypothalamic in origin. As a result it leads to secondary adrenal failure. Adrenal secretion of cortisol and of adrenal androgens is mainly affected; aldosterone secretion is normal. Symptoms of hypocorticotropism include progressive malaise and weight loss. Because aldosterone secretion is intact salt wasting, volume contraction and hypokalemia are not present. Hypoglycemia due to defective neoglucogenesis may occur and is particularly common in children. Symptoms may be more dramatic in the case of abrupt onset. Laboratory assessment includes baseline measurements of ACTH and cortisol and dynamic tests. A low morning value of cortisol (i.e. <3 μg/dl) associated with a low ACTH is diagnostic of severe hypococorticotropism. A value of 9am cortisol over 18 μg/dl excludes hypococorticotropism. For all other values dynamic tests are required. The gold standard test is the insulin stress test (IST). Alternative tests are the glucagon, the metyrapone and the standard (SST) and low Synacthen (LST) tests. The Synacthen tests because of their simplicity and safety have superseded the gold standard IST. Although the LST was considered as a more sensitive test than the SST recent data suggest that there is no difference. A cut-off of 18 μg/dl is considered as a “pass” and is safe assuming that assessment is not close to recent pituitary failure. Confirmation of hypocorticotropism requires replacement therapy. Hydrocortisone is the preferred medication. It is better given in 3 divided doses to a total daily dose of 10–20 mg. Co-administration of GH may increase the dose requirements of hydrocortisone. The dose should also be increased during stress and surgery. The question of whether adrenal androgen replacement is beneficial is still debated. Some studies showed positive effects on the quality of life of 50 mg of DHEA but others fail to confirm this. A therapeutic trial of 3–6 months in patients, particularly women, with relevant symptoms may be justified.