Nelson Syndrome

Incidence: Reported in 8–44% of pts following bilateral adrenalectomy for Cushing disease

More likely in pts with younger age and pregnancy

Lyte imbalances

DI

Vision loss

Challenges specific to type of surgery

Panhypopituitarism

Volume status imbalance

Steroid supplementation

The first case of Nelson syndrome was reported in 1958 by Dr. Del Nelson, who named this condition.

It is also known as post-adrenalectomy syndrome and occurs as result of bilateral adrenalectomy performed for treatment of Cushing disease.

It can develop as long as 24 y after a bilateral adrenalectomy, but the mean age of presentation is 15 y after the adrenalectomy.

Nelson syndrome differs from Cushing disease in that the hypercortisolism cannot occur because of the adrenalectomy, and a pituitary tumor is known to be present.

The pathophysiology of Nelson syndrome is poorly understood. It possibly occurs due to release of the negative feedback that would otherwise suppress high cortisol levels, in turn leading to restoration of CRH production by the hypothalamus going on to stimulate corticotroph neoplasia.

The signs and symptoms of Nelson syndrome are due to the effects of raised ACTH (more than 154 pmol/L) and the pressure of the tumor on surrounding structures, inhibiting release of other pituitary hormones, and thereby leading to panhypopituitarism. The symptoms include hyperpigmentation, headache, and visual disturbances. Increased urine output may suggest development of DI.

ACTH levels are markedly elevated in Nelson syndrome and because of an exaggerated ACTH response to CRH.

Other tests for hormones to assess panhypopituitarism may be done. Thyroid-function tests, prolactin levels, and IGF-1 IGF-BP3 measurement; measure gonadotropin levels in adolescents showing pubertal arrest and urine osmolality and specific gravity to rule out DI.

No clear guideline is provided for periop glucocorticoid replacement, although serum cortisol values less than 3.6 μg/dL should be treated with supplementation.