G462(P) Outcome of equivocal Cortisol responses to Insulin tolerance and Glucagon stimulation tests performed in children with idiopathic short stature (ISS) and idiopathic isolated growth hormone deficiency (IIGHD): Abstract G462(P) Table 1

Abstract

IntroductionThe insulin tolerance (ITT) and glucagon stimulation (GST) tests are used most frequently to assess growth hormone reserve. These tests also stimulate cortisol release. It is not uncommon for patients, with no clinical suggestion of cortisol deficiency, to have equivocal cortisol responses (peak cortisol <500 nmol/L) which may cause unnecessary parental anxiety, further testing and treatment.AimTo explore the outcome of children with idiopathic short stature and isolated idiopathic short stature who had peak cortisol levels <500 nmol/l in the ITT or GST during the period January 2008 to December 2014.ResultsData from 189 (130 M) patients, age 12.0 years ± 4.4 (mean±SD) were studied. 94 underwent a GST and 95 underwent an ITT.In 38 patients (20.1%), age 12.1yrs (1.7–19.2 yrs), peak cortisol levels were <500 nmol/L, of whom 24 patients, (median age 7.7 yrs, 1.7–16.8 yrs) underwent GST (peak cortisol levels 396 nmol/L, 231–491) and 14 patients (median age 14.0 yrs, 5. 2–19.2 yrs) underwent ITT (peak cortisol 461 nmol/L, 408–497).Outcome of these patients who had peak cortisol <500 nmol/l is given in the following Table.Abstract G462(P) Table 1Number of patients n = 38Test, Peak cortisol – median (range) (nmol/l)Outcome16GST, N=15, 364 (238–464) ITT, N=1, 486Passed LDSST6451 (422–486)All had ITT and were treated with hydrocortisone on sick days only. 3 patients had LDSST of whom 2 had peak cortisol levels <500 nmol/L.13GST, N=7, 414 (345–491) ITT, N=6, 482 (408–497)Observation only, remained clinically well. Median period of observation 2.5yrs (range 0.9–7.8 yrs)1469 on ITTMorning cortisol was 457nmol/l1301 on GSTPassed ITT after GST with peak of 541nmol/l1428 on GSTDid not attend 3 appointmentsLDSST: low dose short Synacthen testConclusionOur observations support previous reports that cortisol levels in healthy children may be <500nmol/L on the GST and ITT, and strengthen recommendations for a review in the definitions of ‘normal’ and ‘abnormal’ results.