Isolated adrenocorticotropic hormone deficiency presenting with hypercalcemia in a patient on long-term hemodialysis

The authors report on a 44-year-old female hemodialysis (HD) patient who presented with hypercalcemia secondary to isolated adrenocorticotropic hormone (ACTH) deficiency. She had been suffering from nausea and abdominal pain caused by recurrent esophageal ulcer. Blood calcium (Ca) adjusted for serum albumin concentration was increased to 14.9 mg/dL (3.72 mmol/L) concurrently with fever and hypotension. Serum intact parathyroid hormone (PTH)-related peptide was not elevated, but serum intact PTH and 1,25-(OH)2 vitamin D3 were decreased to 31 pg/mL (ng/L) and 8.1 pg/mL (2.6 pmol/L), respectively. Endocrinologic examination found that plasma ACTH was reduced below 5.0 pg/mL (0.22 pmol/L). A single ACTH stimulation normally increased blood cortisol, whereas a single corticotropin-releasing hormone injection failed to increase plasma ACTH and cortisol. Pituitary magnetic resonance imaging disclosed no enlargement of pituitary gland. Circulating bone formation and absorption markers were not elevated. Blood Ca was normalized shortly after pamidronate disodium administration without glucocorticoid supplementation. This case suggested that secondary adrenal insufficiency caused by isolated ACTH deficiency could be an occult cause of severe hypercalcemia in HD subjects.