Biochemical Discordance in Acromegaly Complicated by Pituitary Apoplexy and Severe Insulin Resistance
https://doi.org/10.15605/jafes.041.S1
- Author:
Jean Mun Cheah
1
;
Fei Bing Yong
1
;
K.J. Lingeswary
1
;
Jen Hoong Oon
1
;
Sharifah Noor Adrilla binti Long Mohd Noor Affendi
1
;
Gayathri Devi A/P Krishnan
1
;
Shazatul Reza binti Mohd Redzuan
1
;
Subashini Rajoo
1
Author Information
1. Endocrine Unit, Department of Medicine, Hospital Kuala Lumpur
- Publication Type:Journal Article
- MeSH:
Acromegaly;
Insulin Resistance;
Pituitary Apoplexy
- From:
Journal of the ASEAN Federation of Endocrine Societies
2026;41(S1):100-
- CountryPhilippines
- Language:English
-
Abstract:
Introduction:Acromegaly is usually diagnosed by elevated age- and
sex-adjusted insulin-like growth factor-1 (IGF-1) levels
reflecting chronic growth hormone (GH) excess. IGF-1 is
preferred as a screening biomarker due to its longer half-life
and reduced pulsatility compared with GH. However, IGF1 levels may be disproportionately low or only modestly
elevated in certain clinical contexts, leading to diagnostic
uncertainty. Pituitary apoplexy is one such condition in
which acute tumor hemorrhage or infarction may disrupt
sustained GH secretion and attenuate IGF-1 production
Case:A 48-year-old female with hypertension, type 2 diabetes
mellitus, and dyslipidemia presented with a 2-day history
of severe headache, vomiting, and visual disturbance, on a
background of progressive acral enlargement over 2 years.
Examination revealed coarse facial features, prognathism,
enlarged hands, and cranial nerve involvement. Magnetic
resonance imaging demonstrated an invasive sellar–
suprasellar pituitary macroadenoma with optic chiasmal
compression and cavernous sinus encasement. Intravenous
dexamethasone was initiated pre-operatively due to a
significant mass effect.
Biochemical evaluation showed markedly elevated
random GH levels (>50 ng/mL) with only mildly elevated
IGF-1 at 1.19 times the upper limit of normal, below the
threshold at which confirmatory oral glucose tolerance
testing may be omitted according to current guidelines.
Other pituitary axes suggested evolving hypopituitarism.
During admission, she developed severe hyperglycemia
with marked insulin resistance, requiring high-dose insulin
therapy (approximately 1.5 U/kg/day). She underwent
urgent transsphenoidal surgery, with histopathology
confirming a pituitary neuroendocrine tumor with extensive
hemorrhage and infarction, consistent with pituitary
apoplexy. Postoperatively, GH levels were suppressed to
<5 ng/mL, insulin requirements decreased markedly, and
hormone replacement was initiated for secondary adrenal
insufficiency and central hypothyroidism.
Conclusion:This case highlights that IGF-1 levels below conventional
diagnostic thresholds do not exclude clinically significant
acromegaly, particularly in the setting of pituitary
apoplexy. Integration of clinical phenotype, GH levels, and
imaging findings is essential to avoid diagnostic delay and
ensure timely management.
- Full text:2026080416294782748EP_A144.pdf
