Evaluation of pituitary-adrenal function after pituitary surgery

A short overnight metyrapone test and a 30-min ACTH test were performed in ten patients after pituitary surgery. At the initial testing 2 weeks after surgery the 30-min ACTH test was abnormal in two patients while normal increases in s-cortisol were observed in eight patients. These eight patients also had normal responses to ACTH when re-tested after 6-19 months. The short metyrapone test was a much more sensitive indicator of functional disturbances in pituitary/adrenal function. Two weeks after surgery the test was abnormal in seven of the patients. After 6-19 months some normalization of the short metyrapone test had occurred, probably due to disappearance of postoperative oedema and haematoma. However, the test was still abnormal in three patients having normal responses during the 30-min ACTH test. It is suggested that both tests are performed in such patients to specify a high risk group, i.e. both tests abnormal, and a low risk group with a normal 30-min ACTH test but subnormal responses during the short metyrapone test. This would be of help in the decision on cortisol supplementation and offer a high degree of safety for the patients.