Cushing syndrome: current concepts of diagnosis and therapy.

A variety of diagnostic advances including radioimmunoassay of adrenocorticotropic hormone (ACTH) have increased the number of methods for laboratory investigation of Cushing syndrome.* However, experience with these procedures has led to a recognition of their limitations. We have developed an algorithm which incorporates these newer techniques and minimizes the number of procedures required to diagnose the various causes of Cushing syndrome. At present, we recommend pituitary surgical operations for pituitary-dependent Cushing syndrome because we believe this disease is caused by the development of a pituitary ACTH-secreting tumor.