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Low- and standard-dose corticotropin and insulin hypoglycemia testing in the assessment of hypothalamic-pituitary-adrenal function after pituitary surgery.

Authors :
Courtney CH
McAllister AS
Bell PM
McCance DR
Leslie H
Sheridan B
Atkinson AB
Source :
The Journal of clinical endocrinology and metabolism [J Clin Endocrinol Metab] 2004 Apr; Vol. 89 (4), pp. 1712-7.
Publication Year :
2004

Abstract

The optimal means of assessing the integrity of the hypothalamic-pituitary-adrenal (HPA) axis after pituitary surgery remains controversial. We compared low-dose (1 micro g iv) and standard-dose (250 micro g im) corticotropin tests performed 1 and 4-6 wk after pituitary surgery with an insulin hypoglycemia test performed at 4-6 wk. Forty-one patients (21 male and 20 female; median age, 52 yr; range, 23-73 yr) who had undergone pituitary surgery were studied (Cushing's disease excluded). Twenty-two of the 41 patients had normal cortisol responses to all tests both at 1 and 4-6 wk after surgery. Eight patients had subnormal cortisol responses to all tests. Of the 11 patients with discrepant results, seven had subnormal responses only after the low-dose corticotropin test; the remaining four patients had borderline responses to one or more tests. At 4-6 wk after surgery, subjects with a 30-min serum cortisol after standard-dose corticotropin of less than 350 nmol/liter (12.7 micro g/dl) consistently had a subnormal response to hypoglycemia, and those with a serum cortisol greater than 650 nmol/liter (23.6 micro g/dl) had a normal response to hypoglycemia. Definitive testing of the HPA axis using the standard-dose corticotropin test can be carried out provided it is performed at least 4 wk after pituitary surgery. A 30-min cortisol level greater than 650 nmol/liter (23.6 micro g/dl) indicates adequacy of the HPA axis, and a level of less than 350 nmol/liter (12.7 micro g/dl) indicates ACTH deficiency. No further testing is then required. An intermediate level of 350-650 nmol/liter (12.7-23.6 micro g/dl) warrants further assessment using the insulin hypoglycemia test.

Details

Language :
English
ISSN :
0021-972X
Volume :
89
Issue :
4
Database :
MEDLINE
Journal :
The Journal of clinical endocrinology and metabolism
Publication Type :
Academic Journal
Accession number :
15070935
Full Text :
https://doi.org/10.1210/jc.2003-031577