Hypothalamic hypopituitarism after pituitary apoplexy in acromegaly

Pituitary apoplexy in acromegaly is an uncommon event having been recorded approximately 30 times in the English literature. This report records two additional cases that included growth hormone measurements and an assessment of pituitary function. The apoplectic event developed spontaneously in one, and in the other it developed within two weeks of completing a course of radiotherapy to the pituitary gland. Autocure of the acromegaly was apparent. Basal levels of growth hormone were in the normal range but failed to change with provocative stimuli. Luteinizing hormone and follicle-stimulating hormone titers, although detectable, were inappropriately low for the degree of hypogonadism. Pituitary insufficiency was associated with a significant thyroid-stimulating hormone response to protirelin in one patient tested. It is suggested that these experiments of nature lend credence to the proposal that the hypothalamus may play a critical role in the perpetuation of growth hormone hypersecretion in some patients with acromegaly.