Assessing the HPA axis in patients with pituitary disease: a UK survey.
OBJECTIVE
Assessing the integrity of the hypothalamic-pituitary-adrenal (HPA) axis following pituitary surgery is necessary to determine the requirement for glucocorticoid replacement therapy, but there remains controversy about the optimum way to measure this.


METHODS
Postal questionnaire survey among UK endocrinologists to evaluate the current methods used.


RESULTS
The response rate was low (81 out of 598 questionnaires mailed), although 85% were consultants. Fifty-five percent measured 9:00 h plasma cortisol in the immediate postoperative phase. Most carried out definitive testing between 4 and 12 weeks: 36% routinely used the insulin tolerance test (ITT), 59% used the short synacthen test (SST). The 30-min cortisol value was used by 67% as a 'pass' when interpreting the results. Others included cortisol measurement at 60 min (17%) or incremental value (7%). For long-term follow-up of patients not rendered ACTH-deficient by surgery, 64% used the SST for patients who had received radiotherapy. If patients had not had radiotherapy, 42% used the SST, whereas 33% did no routine testing unless the patient was symptomatic or there was evidence of tumour recurrence on imaging. If patients were symptomless but 'failed' the chosen test, 28% still treated the patient with glucocorticoid replacement, 38% retested before treatment and 24% recommended glucocorticoid cover for when unwell or 'stressed'. Fifty-six percent used hydrocortisone at doses of 20 mg/day as replacement therapy.


CONCLUSIONS
Thus, assessment of the HPA axis remains controversial. Although the SST is becoming more popular, there is still considerable variation in the interpretation of results and, in particular, the decision of whether or not to treat with lifelong glucocorticoid replacement therapy.
Reynolds
Rebecca M
RM
Endocrinology Unit, Centre for Cardiovascular Sciences, University of Edinburgh, Queen's Medical Research Institute, Little France Crescent, Edinburgh EH16 4TJ, UK. r.reynolds@ed.ac.uk
Stewart
Paul M
PM
Seckl
Jonathan R
JR
Padfield
Paul L
PL
D000324:Adrenocorticotropic Hormone; D004704:Endocrinology; D005500:Follow-Up Studies; D005934:Glucagon; D005938:Glucocorticoids / Q000627:therapeutic use; D019538:Health Care Surveys; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D007328:Insulin; D018579:Patient Selection; D010900:Pituitary Diseases / Q000188:drug therapy / Q000378:metabolism*; D010901:Pituitary Function Tests; D010913:Pituitary-Adrenal System / Q000503:physiopathology*; D010818:Practice Patterns, Physicians'; D011795:Surveys and Questionnaires; D006113:United Kingdom
D005938:Glucocorticoids; D007328:Insulin; D000324:Adrenocorticotropic Hormone; D005934:Glucagon; D006854:Hydrocortisone