What is Cushing's syndrome?

Causes and Symptoms

Cushing’s syndrome is a group of abnormalities that result from either excessive levels of hormones produced by the outer layer of the adrenal glands
or the taking of steroid hormones. The primary source of the disorder is the hormone cortisol. This condition is typically triggered by an excess production of adrenocorticotropic hormone (ACTH)
from the pituitary gland. ACTH in turn stimulates the adrenal glands to produce hormones, particularly cortisol. Excessive production of ACTH may result from a pituitary gland tumor or a tumor associated with other organs or as a side effect from taking steroid hormones used to treat asthma, rheumatoid arthritis, and other serious diseases. Adrenal gland
tumors
also produce excess amounts of cortisol. Though extremely rare, an inherited tendency to develop endocrine gland tumors is another cause of Cushing’s syndrome.

Since the hormones produced by the adrenal glands regulate processes throughout the body, excess production can cause widespread disorders. Some of the more common symptoms of Cushing’s syndrome are a rounded face, an obese trunk with thin arms and legs, fat pads over the neck and shoulders, purple stretch marks on the skin, easy bruising, muscle weakness, poor wound healing, fractures in weakened bones, high blood pressure, diabetes mellitus, emotional instability, and severe fatigue. Men can experience diminished desire for sex, while women may experience increased hairiness, acne, and decreased or absent menstrual periods. Children are usually obese, and their growth rate is slow.

Treatment and Therapy

Cushing’s syndrome is treated by restoring the hormonal balance within the body, which may take several months. If Cushing’s syndrome is left untreated, it can lead to death. The disease is diagnosed through blood and urine tests to determine excess amounts of cortisol. Pituitary tumors and tumors at other locations in the body that have been diagnosed as producing ACTH are surgically removed, when possible, or are treated with radiation or chemotherapy. Cortisol replacement therapy is provided after surgery until cortisol production resumes. Lifelong cortisol replacement therapy may be necessary. If steroids are not being used to control a life-threatening illness, then their use should be discontinued.

Adrenal and pituitary tumors are always surgically removed. The remaining adrenal gland, which has usually diminished in size as a result of inactivity, will return to its normal size and function. As it is doing so, steroid hormones are administered to supply the needed cortisol and then tapered off over time. Some tumors may recur after surgical excision.

Perspective and Prospects

The first diagnosis of Cushing’s syndrome was made by Harvey Cushing in 1912. In 1932, he linked the syndrome to an abnormality in the pituitary gland that stimulated an overproduction of cortisol from the adrenal glands; this condition is known as Cushing's disease. Pituitary tumors cause approximately 70 percent of cases of Cushing's syndrome. The syndrome is more common in women than in men, with most cases occurring between the ages of twenty-five and forty-five. The disease can be very serious, possibly even fatal, unless diagnosed and treated early.

Bibliography

A.D.A.M. Medical Encyclopedia. "Cushing Syndrome." MedlinePlus, December 11, 2011.

Badash, Michelle. "Cushing's Syndrome." HealthLibrary, May 1, 2013.

Fox, Stuart Ira. Human Physiology. 11th ed. Boston: McGraw-Hill, 2010.

Kronenberg, Henry M., et al., eds. Williams Textbook of Endocrinology. 11th ed. Philadelphia: Saunders/Elsevier, 2008.

National Endocrine and Metabolic Diseases Information Service. "Cushing's Syndrome." National Institutes of Health, April 6, 2012.