RESUMEN
Isolated ACTH deficiency is a rare cause of secondary adrenocortical insufficiency. Adrenal crisis in isolated ACTH deficiency is less common compared to primary adrenal insufficiency, but isolated ACTH deficiency is an important cause of hypoglycemia. Recently we experienced a 41-year-old man admitted because of mental confusion. On admission, plasma glucose and sodium concentration were 1.7, 132 mmol/L, respectively. Basal plasma ACTH and cortisol levels were low and other pituitary hormone showed normal response to combined pituitary stimulation test except growth hormone. Plasma ACTH concentration remained low even after intravenous injection of ovine corticotropin releasing factor. It suggest that the defect of ACTH secretion was apparently due to intrinsic pituitary rather than hypothalamic disease. The sellar CT showed the fossa to be filled by cerebrospinal fluid. After treatment with glucocorticoid, he had no further evidence of hypoglycemia and hyponatremia. In conclusion, we report a case of isolated ACTH deficiency with empty sella.