A discussion on stress should include recognition of Dr. Hans Selye. His classic work on stress ( The Stress of Life , McGraw- Hill Book Co., .) and his many other publications report “that our various internal organs, especially the endocrine glands and the nervous system, help to adjust us to the constant changes which occur in and around us. He calls this adjustment the General Adaptation Syndrome. Selye concluded that the adrenals were the body’s prime reactors to stress. He stated that the adrenals “…are the only organs that do not shrink under stress; they thrive and enlarge. If you remove them, and subject an animal to stress it can’t live. But if you remove them, and then inject extract of cattle adrenals (cortex), stress resistance will vary in direct proportion to the amount of the injection, and even be put back to normal.” Likewise a person’s stress resistance will vary with the competence of his adrenals, but continually stressing the adrenals finally depletes them.
In the ., the most common cause (about 75%) of primary adrenal insufficiency in adults is an autoimmune process. It may occur with other autoimmune conditions that affect other glands, such as the thyroid. The rest of the time, Addison disease is due to other causes, such as tuberculosis , a common cause in areas of the world where tuberculosis is more prevalent , other chronic infections, especially fungal infections , bleeding into the adrenal glands ( hemorrhage ) and the spread of cancer into the adrenal glands. Rarely, it may be due to a genetic abnormality of the adrenal glands.