A Case of Prolonged Undetected Hypoglycemia Even After Weight Gain in a Patient With Anorexia Nervosa

Abstract

A 23-year-old woman with a body weight of 29 kg (body mass index, 11.3 kg/m²) was diagnosed with anorexia nervosa on X. She was admitted to our department on X+1 due to prolonged hypoglycemia. On admission, her body weight was 50 kg (body mass index, 20.3 kg/m²), and her fasting plasma glucose level was 54 mg/dL. Hypoglycemia occurred frequently early in the morning under fasting conditions. Therefore, a fasting test was performed. After 24 h of fasting, the plasma glucose level was 38 mg/dL, and hypoglycemia unawareness was observed, while plasma immunoreactive insulin was suppressed. There were no increases in the levels of adrenocorticotropic hormone (ACTH) or cortisol in response to the hypoglycemia. Corticotropin-releasing hormone stimulation showed normal responses of ACTH and cortisol. The patient was therefore diagnosed with possible hypoglycemia associated with a reduced hypothalamic response to hypoglycemia. Treatment with oral hydrocortisone 15 mg daily was started and then tapered and discontinued, after which the patient experienced no more episodes of hypoglycemia. The patient in the present study experienced prolonged hypoglycemia even after weight gain. The etiology was considered to be due to possible hypoglycemia associated with a reduced hypothalamic response to hypoglycemia.