Evaluation of pituitary function

The improved survival of patients irradiated for central nervous system (CNS) and head and neck malignancy plus the recognition of the frequency of hypopituitarism following traumatic brain injury and other insults to the CNS has greatly increased the number of patients requiring long-term monitoring of pituitary function. The investigation of pituitary reserve requires knowledge of the risk factors for the development of hypopituitarism and thus biochemical testing is underpinned by the need for a meticulously taken medical history and careful examination of the patient. Radiology may be of value in establishing the etiology of hypopituitarism but the diagnosis is based on biochemical evaluation. This chapter provides a rational approach to the investigation of patients at risk of hypopituitarism including descriptions of how to undertake and interpret basal and dynamic tests of pituitary function.