Pituitary disorders: Prolactinomas, acromegaly, and pituitary apoplexy

This chapter discusses pituitary disorders, focusing on prolactinoma, acromegaly, and pituitary apoplexy. A prolactinoma (prolactin-secreting pituitary tumour) is defined as a macroprolactinoma when it is >1 cm in diameter, and as a microprolactinoma when it is <1 cm in diameter. Acromegaly occurs as a result of excessive secretion of growth hormone (GH) and, consequently, of insulin-like growth factor 1 in adults. It is termed pituitary gigantism in the paediatric setting when excessive GH secretion occurs prior to epiphyseal plate fusion. Pituitary apoplexy is infarction of the pituitary gland, via haemorrhage or ischaemia, with resulting hypopituitarism. The etiologies, symptoms, diagnosis, investigation, prognosis, and treatment of these pituitary disorders are also discussed.