Nelson's Syndrome - Pathophysiology

Pathophysiology

Removal of both adrenal glands, or bilateral adrenalectomy, is an operation for Cushing's syndrome. Removal of both adrenals eliminates production of cortisol, and the lack of cortisol's negative feedback can allow any preexisting pituitary adenoma to grow unchecked. Continued growth can cause mass effects due to physical compression of brain tissue, along with increased production of adrenocorticotrophic hormone (ACTH) and melanocyte stimulating hormone (MSH). The accompanying increase in MSH is due to ACTH and MSH being derived from a common precursor peptide, known as proopiomelanocortin (POMC).