Endocrine Abstracts

Introduction: ACTH deficiency is life-threatening, but difficult to differentiate from ACTH suppression especially in children and young people (CYP) receiving perioperative corticosteroids for pituitary tumour surgery. In our experience, ACTH is the most, and GH the least robust anterior pituitary hormone, with LH/FSH and TSH intermediate in hierarchical loss.

Aims: To assess potential misdiagnosis of ACTH suppression versus deficiency and time to adrenal recovery in a longitudinal cohort of CYP with craniopharyngioma treated at our centre over 26 years. To assess whether pre-dose 8am plasma ACTH detectability might predict ACTH recovery.

Methods: Fifty-three patients (29 male) with craniopharyngioma were identified from local neuroendocrine databases and their clinical records reviewed.

Results: At diagnosis, patients were aged 6.87 (1.12–17.18) years and followed for 6.66 (1.35–26.73) years. Of the 53 patients, 9(16.98%) diagnosed at 6.71 (4.63–14.15) years never required hydrocortisone, though 8/9 (88.9%) were GH deficient, 6/9 (66.7%) TSH and 5/9 (55.6%) LH/FSH deficient and 1/9 (11.1%) ADH deficient at a 6.53 (1.35–17.53) year follow-up when BMI and height SDS were +2.14 (+0.40 to +4.79) and −0.17 (−2.19 to +2.08) respectively. Initial and last ACTH were 17.9 ng/l (14.7–20.6) and 15.0 ng/l (14.4–41.5) respectively. A further 6/53 (11.3%) patients diagnosed at 8.22 (4.63–15.19) years old were treated for presumed ACTH deficiency (peak cortisol reserve <117 nmol/l) but had “recovered” with intact cortisol reserve 3.08 (2.38–10.33) years later. BMI and height SDS were +1.03 (−0.20 to +2.93) and +0.05 (−1.11 to +1.42) respectively. All had detectable ACTH 36.2 ng/l (13.9–52.9) at recovery and although all were GH deficient, only 5/6 (83.3%) had deficiency in LH/FSH, 4/6 (66.7%) in TSH and 2/6 (33.3%) in ADH. The remaining 38/53 (71.7%) patients, diagnosed at 6.28 (1.12–17.18) years, continued showing undetectable ACTH levels <5 ng/l and require cortisol, GH and thyroxine replacement 5.94 (1.43–26.73) years later, whilst all but one of the remaining 32 who were post-pubertal (31/32 (96.9%)) were LH/FSH deficient and 31/38 (81.6%) ADH deficient. There was a significant difference in TSH (P<0.01) deficiency between CYP with and without cortisol requirement.

Conclusions: Overdiagnosing ACTH deficiency after pituitary tumours may delay adrenal recovery, aggravate hypothalamic obesity and be erroneously attributed to surgery or radiation. The 13.6% adrenal recovery demonstrated suggests ACTH suppression, which may increase with time. We suggest a detectable pre-dose early morning ACTH >10 ng/l in CYP on physiological replacement and the absence of concomitant TSH and post-pubertal LH/FSH deficiency should alert physicians to readdress the ongoing need for hydrocortisone in a population prone to obesity and its complications.