GNRH1 and adenoma: Based on the results of the ACTH continuous load test, triple anterior pituitary stimulation test with corticotropin-releasing hormone (CRH), thyrotropin-releasing hormone (TRH), and gonadotropin-releasing hormone (GnRH), growth hormone-releasing peptide-2 (GHRP-2) load test, and insulin hypoglycemic load test, no abnormalities were found in his pituitary functions other than ACTH-cortisol, and no history of trauma or adenoma lesions, leading to a diagnosis of a sudden isolated ACTH deficiency.