Detailed Information on Nelson Syndrome

Nelson's syndrome is a rare condition. Nelson syndrome is a disorder characterized by abnormal hormone secretion, extension of the pituitary gland (hypophysis), and the development of big and invasive growths known as adenomas. It occurs in an evaluated 15 to 25 percent of people who undergo surgical removal of the adrenal glands for Cushing disease. In Cushing’s disease, blood cortisol is elevated due to excessive secretion of the hormone ACTH by a pituitary adenoma. ACTH signals the adrenal gland to produce cortisol. The hormone ACTH, in excessive amounts, can stimulate pigment production in the skin.

Symptoms related with Nelson syndrome include intense skin discoloration (hyperpigmentation), headaches, vision impairment, and the cessation of menstrual periods in women. Nelson syndrome is more common in women than men. There is no medical treatment that will help to shrink the microadenoma, but drug therapy may assist in alleviating the symptoms caused by a high ACTH. Bromocriptine, cyproheptadine, and caloric acid can reduce ACTH secretion but do not return it to normal. Radiotherapy is important in the treatment of patients with Nelson syndrome.

Radiotherapy, preferably with stereotactic radiation, controls tumor growth in the majority of patients with residual tumor growth after surgery. Fractionated external beam radiotherapy or stereotactic radio surgery can be used depending on tumor size and location. Modern techniques with high power linear accelerators cause less radiation scatter and so less collateral damage. Radiotherapy is associated with serious long-term problems, including learning and memory difficulties, visual damage and risk of secondary tumours. It is the best treatment for large tumors that produce acute compression of the optic apparatus and other vital structures.

Trans-sphenoidal surgery gives the lowest risk of injury of the hypothalamus. If removal is incomplete or where there is invasion, adjunctive irradiation decreases the rate of recurrence and helps the prognosis. Treatment using protons rather than photons has improved effectiveness and has affected a cure in some patients in whom surgery has been unsuccessful. Use of a gamma knife to focus the radiotherapy beam offers a further refinement. Long term assessment of pituitary function is required with hormone replacement therapy as required. Blood pressure should also be monitored.