Long-term use of exogenous
glucocorticoids leads to the suppression of the hypothalamic-pituitary-adrenal axis. Therefore, if the
glucocorticoid is withdrawn abruptly, patients will develop
adrenal insufficiency. Hypercalcaemia is a rare but well-known complication of
adrenal insufficiency. However, hypercalcaemia is a rare presentation of
glucocorticoid-induced
adrenal insufficiency (GI-AI). A 62-year-old patient with a past history of
diabetes mellitus, ischaemic
heart disease,
stroke,
hypertension and dyslipidaemia presented with
polyuria, loss of appetite, malaise and
vomiting for a duration of 2 months. His ionized
calcium level was high at 1.47 mmol/L. Intact
parathyroid hormone was suppressed (4.3 pg/mL) and
vitamin D was in the insufficient range (24.6 ng/mL). Extensive evaluation for solid organ or haematological
malignancy including contrast-enhanced CT chest, abdomen, pelvis,
multiple myeloma workup and multiple tumour markers were negative. His synacthan-stimulated
cortisol was undetectable thus confirming
adrenal insufficiency. His
adrenocorticotrophic hormone level was 3.82 pg/mL (4.7-48.8) excluding
primary adrenal insufficiency. His MRI brain and other
pituitary hormones were normal. Further inquiry revealed that the patient had taken over-the-counter
dexamethasone on a regular basis for
allergic rhinitis for more than 2 years and had stopped 2 weeks prior to the onset of symptoms. Therefore, a diagnosis of GI-AI leading to
hypercalcemia was made. The patient was resuscitated with intravenous fluids and replacement doses of oral
hydrocortisone were started with a plan of prolonged tailing off to allow the endogenous adrenal function to recover. His
calcium normalized and he made a complete recovery.
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