Cushing's Syndrome

Definition

Cushing's Syndrome is a hormonal disorder caused by an abnormally high circulating level of corticosteroid hormones. Cushing’s syndrome is also known as hypercortisolism.

Description

Cushing's syndrome may be produced by an adrenal gland tumor causing excessive secretion of corticosteroids, a prolonged administration of corticosteroid drugs, or by an enlargement of both adrenal glands, due to a pituitary tumor (known as Cushing’s disease).

Corticosteroid drugs are widely used for inflammatory conditions such as rheumatoid arthritis, inflammatory bowel disease and asthma. The pituitary gland controls the activity of the adrenal gland by producing the hormone ACTH (adrenocorticotropic hormone), which stimulates the cortex (outer portion) of the adrenal gland to grow. Overactivity of a tumor of the pituitary can thus lead to overproduction of ACTH, overgrowth of the adrenal glands and an excess secretion of the corticosteroids. Some lung cancers and various other tumors may also secrete ACTH with similar results.

Causes and Risk Factors

Cushing's syndrome may occur at any age, but is most common in middle age. Most cases today are caused by excessive, prolonged use of corticosteroid drugs, but these cases are usually mild. The patient is often described as having cushingoid features rather than full-blown Cushing's syndrome.

Cases caused by pituitary overactivity (Cushing's disease) are much more common in women, and those caused by lung tumors are more common in men.

Symptoms

People with Cushing's syndrome may have a characteristic appearance. The face appears round and red, the trunk tends to become obese with a humped upper back and the limbs become wasted. Acne may develop and purple stretch marks (striae) may appear on the abdomen, thighs and breasts. The skin is thin and bruises easily. The bones become weakened and are at increased risk of fracturing. Women may become increasingly hairy.

Affected people are more susceptible to infection and may suffer from stomach or duodenal ulcers. Mental changes often occur, including depression, paranoia and sometimes euphoria. Insomnia may be a problem. Patients may develop hypertension and edema. About one-fifth of all patients develop diabetes mellitus. In children, Cushing's syndrome can suppress growth.

Diagnosis

Anyone who suspects that they might have Cushing's syndrome should see a physician. Diagnosis requires the measurement of adrenal cortex hormones in the blood and urine. Normally, cortisol levels in the blood are high on awakening and decrease during the day. In the person with Cushing's syndrome, cortisol levels are high all of the time. Various tests can determine whether the cause of the syndrome is a tumor of the adrenal gland or elsewhere.

Treatment

Cushing's syndrome is treated by restoring a normal balance of hormones. This may involve surgery, radiation treatments or drugs. Tumors on the adrenal glands are removed by surgery. If there is a tumor on just one adrenal gland, the other gland usually shrinks and ceases normal productivity. Hormone supplements are usually given before surgery and must be taken for weeks and sometimes months after surgery, until the second gland recovers normal function.

In a rapidly worsening case of Cushing's syndrome, in which the cortex is greatly enlarged on both sides, one treatment is to remove both adrenal glands. This is usually a last-resort measure.

More commonly, another method is tried first, such as chemotherapy - radiation treatments of the pituitary gland (to weaken it and lower its output of ACTH) - or removal of any benign growths of the pituitary gland.

If other measures fail, the adrenal glands are removed, and the patient must take daily supplements of adrenal cortex hormones for the rest of his or her life.

If Cushing's syndrome is being caused by production of ACTH by a cancerous tumor in a part of the body other than the adrenal glands, the cancer is removed, if possible. However, in many cases it is inoperable, so drugs to suppress production of the adrenal glands are given.

Cushing's syndrome can be a very serious disease unless detected and treated early. The outlook is best for those whose condition is caused by noncancerous growths and who receive early treatment.

Questions to Ask Your Doctor

What tests need to be done to diagnose or to determine the cause?

How serious is the condition?

What treatment do you recommend?

How long will it take to relieve symptoms? Will the characteristic appearance disappear and return to normal?

Will surgery be required? If so, what is the procedure? And what can be expected after the surgery?

Will any medication be prescribed? What are the side effects?