Isolated Adrenocorticotropic Hormone Deficiency Presenting With Delirium

“Mr. A,” a 74-year-old man without a history of neuropsychiatric disease, complained of diarrhea followed by fatigue and a loss of appetite. A general practitioner found hyponatremia, and an intravenous drip infusion of normal saline solution was performed for 1 week. However, the patient’s fatigue and loss of appetite remained. Two weeks later, he went into a delirious state and was admitted to our psychiatric unit.

On admission, a physical examination revealed weakness of the patient’s extremities. He did not have a history of receiving glucocorticoids or skin and mucosal pigmentation. Blood examinations showed hyponatremia (121 mEq/l), neutropenia, and eosinophilia (white blood cell: 4600/ml [20.3% neutrophils and 8.3% eosinocytes]). Potassium and plasma glucose were within normal limits. These findings led us to consider the possibility of adrenocortical insufficiency, and we consulted an endocrinologist for further evaluation. Additional tests revealed low levels of cortisol (1 mg/dl) and adrenocorticotropic hormone (5.9 pg/ml). The growth hormone, luteinizing hormone, follicle-stimulating hormone, all of the thyroid hormones, and prolactin levels were within normal limits. A quad pituitary stimulation with the corticotropin releasing hormone, growth hormone releasing hormone, thyrotropin releasing hormone, and gonadotropin releasing hormone caused a normal elevation of growth hormone, thyroid-stimulating hormone, prolactin, luteinizing hormone, and follicle-stimulating hormone levels. However, the adrenocorticotropic hormone level remained low. A magnetic resonance imaging study showed no tumor or atrophy of the pituitary. These results excluded panhypopituitarism and led us to diagnose the patient with secondary adrenocortical insufficiency because of isolated adrenocorticotropic hormone deficiency. A daily dose of hydrocortisone (20 mg by mouth) was administered, which resulted in a dramatic improvement of the patient’s consciousness level and hyponatremia, followed by recovery from the delirium in 3 days.