Physiology and Diseases of the Hypothalamic-Pituitary Axis in the Elderly

The most common endocrine changes of healthy aging are declines in GH and IGF-I, ovarian steroids in postmenopausal women, testosterone (T) in men, and DHEA. Aging is associated with an increased frequency of pituitary tumors, detected incidentally in 10%-25% of hypothalamic-pituitary MRIs performed in older persons. Most (60%-80%) are slow growing, nonfunctioning, micro-incidentalomas. Clinical manifestations are most often related to a macroadenoma mass effect (e.g., visual disturbances with chiasmatic compression). Nearly 20% of patients perceive symptoms of hormone deficiency or excess. At least one hormone deficit (mostly gonadotropins and/orGH) is shown by testing in most patients with nonfunctioning pituitary adenomas, and hormonal excess is demonstrated in 20%. Detailed neuroradiological and functional diagnosis of patients with pituitary tumors is reviewed. Transsphenoidal surgery is safe and effective in elderly patients with pituitary tumors, although there is some increased comorbidity and anesthetic risk. Adjuvant radiotherapies are only indicated in elderly patients with tumor reexpansion. Therapy with glucocorticoids, L-T4, T, GH and DDAVP should be individualized to account for physiological changes of aging and associated pathologies. Hormone replacement therapy with glucocorticoids, L-T4, T in men, GH and DDAVP are reviewed in detail.