Medical management of hypopituitarism in patients with pituitary adenomas.

Hypopituitarism is a disease complex with variable clinical manifestations. Recent studies have improved our understanding of its pathophysiology, particularly in patients with pituitary adenomas. In that setting, hypopituitarism was previously considered a permanent and irreversible process, requiring life-long hormone replacement therapy. While this could be true in some instances, recent data demonstrated recovery of pituitary function in a large number of patients with hypopituitarism following surgical decompression. Mechanical compression of portal vessels and the pituitary stalk, by the expanding adenoma was postulated to be the predominant mechanism causing hypopituitarism in this setting. Since portal vessels also provide blood supply to the anterior lobe, ischemic necrosis of portions of the pituitary can occur as a result of increased and prolonged compression by the expanding adenoma. Recent data demonstrated increases in intrasellar pressure (ISP) in patients with pituitary macroadenomas, particularly those with hypopituitarism. The data showed that ISP measurements correlated positively with the serum prolactin levels but not with tumor sizes. It is postulated that increased ISP has predominant role in the pathogenesis of hypopituitarism in patients with pituitary adenomas while. The increase in ISP results in decreased blood flow through the portal vessels and the pituitary stalk. The latter will result in diminished delivery of hypothalamic hormones to the anterior pituitary and may also cause ischemia and/or necrosis in some portions of the normal gland. Recovery of pituitary function can thus be anticipated after surgical decompression, in patients who have viable pituitary cells. Understanding the pathophysiology of hypopituitarism and recognizing the probability for recovery of function should be emphasized in the management of patients with this disease. An important aspect of the management is patients' education about their disease, including the use of medic alert identification. The managing physician should appreciate the variable clinical manifestations of the disease and the possible occurrence of other associated neuroendocrine, neurological and neuro-ophthalmologic signs and symptoms. Treatment of hypopituitarism should not be rigid but instead, always individualized. Management should take into consideration the patients' age, sex, education, original disease process and clinical history.