A Single Episode of Hypoglycemia as a Possible Early Warning Sign of Adrenal Insufficiency

A 65-year-old woman without a history of diabetes mellitus was admitted for elective total knee arthroplasty for osteoarthrosis. There were no specific complaints except for knee flexion contractures, and the results of preoperative tests were unremarkable. On the day of surgery, the patient suffered from a hypoglycemic attack (52 mg/dL) after preoperative overnight fasting. A dextrose infusion immediately corrected the hypoglycemia, and a total knee arthroplasty was then performed. Although a hypoglycemic attack did not recur, further evaluation was required because of nausea that persisted after surgery. The morning serum cortisol level was 0.15 µg/dL with undetectable adrenocorticotropic hormone (ACTH), and the insulin-like growth factor-1 level was 9 ng/mL. An empty sella and bilateral adrenal atrophy were evident in imaging studies. ACTH and growth hormone (GH) did not respond to testing with corticotropin-releasing hormone and GH-releasing peptide-2, respectively. While serum cortisol did not increase on a rapid ACTH stimulation test, urinary free cortisol excretion responded to a prolonged ACTH stimulation test. Finally, the patient was diagnosed as having empty sella syndrome with ACTH and GH deficiencies. After the administration of hydrocortisone as maintenance replacement therapy, the patient's prolonged postoperative nausea disappeared. Adrenal insufficiency is latent in patients with hypoglycemia episodes. Because patients with adrenal insufficiency require appropriate perioperative corticosteroid supplementation, clinicians should give priority to identifying the underlying etiology of hypoglycemia over non-urgent elective surgery when these co-occur.