Cushing's Syndrome in Brief

Cushing's syndrome, an uncommon disorder named for the 20th century American surgeon who identified it, is caused by elevated blood levels of cortisol. Cortisol, an essential corticosteroid hormone, is produced by the cortex of the adrenal glands, grape-sized organs located above each kidney that form part of the body's endocrine system. Cortisol secretion is stimulated by the release of adrenocorticotropic hormone (ACTH) from the pituitary gland.

Cushing's syndrome is due to overproduction of cortisol by the adrenals or administration of excessive amounts of cortisone in the treatment of a number of diseases. The disorder is known as Cushing's disease when symptoms are due to increased production of ACTH by a tumor in the pituitary gland. Common complications are hypertension, diabetes mellitus, osteoporosis and muscle weakness. Both Cushing's syndrome and Cushing's disease respond well to treatment.

Causes

Large or long-term doses of oral corticosteroid medications, prescribed to treat disorders such as rheumatoid arthritis, inflammatory bowel disease or asthma, are now the most common cause of Cushing's syndrome. An adrenal tumor or overgrowth (hyperplasia) of adrenal cortex cells may also cause Cushing's syndrome. A pituitary tumor that secretes excess ACTH overstimulates cortisol production by the adrenal glands and causes Cushing's disease.

Occasionally, tumors elsewhere in the body, such as in the lungs, may produce excess ACTH and are known as ectopic ACTH-producing tumors.

Symptoms

• A round or "moon-shaped" face 
• Fat accumulation on the torso and between the shoulder blades 
• Thin legs and arms
• Fatigue and muscle weakness
• Skin changes, including easy bruising; acne; purple stretch marks on the abdomen, thighs and breasts; thin skin; a reddish appearance of the face
• Insomnia
• Changes in mental state, such as mood swings, depression, paranoia or euphoria
• In men: growth of breasts (gynecomastia); impotence
• In women: growth of hair (hirsutism); the cessation of menstruation (amenorrhea)
• Back or hip pain from bone fractures due to osteoporosis
• Call a doctor if you develop excess fat on your face and torso, accompanied by any of the other symptoms of Cushing's syndrome.

Prevention

If you are taking corticosteroids on a long-term basis, ask your doctor about taking the lowest possible doses of these medications.

Diagnosis and treatment

A diagnosis will be based in part on the results of blood and urine tests to measure levels of adrenal hormones and CT (computed tomography) scans or MRI (magnetic resonance imaging) of the abdomen or skull to image the pituitary gland.

If Cushing's syndrome is caused by long-term treatment with corticosteroid medications, your doctor may gradually reduce the dosage and switch you to another form of treatment, if possible. Never stop taking corticosteroids on your own, because serious side effects may occur; slow withdrawal should be planned and supervised by a doctor.

A pituitary or adrenal tumor can be surgically removed. Radiation therapy, either alone or in conjunction with surgery, may be used to treat tumors.

Medications that inhibit the secretion of cortisol, such as ketoconazole, aminoglutethimide, metyrapone or mitotane, may be prescribed when surgery is impossible or unsuccessful or when the tumor is malignant.

Hormone replacement therapy (temporary or lifelong) may be necessary to supplement or replace adrenal and thyroid hormone after surgery or radiation treatment to the pituitary.

Last Updated: 1/15/2003
The Johns Hopkins University 1996-2003.  All rights reserved.  This information is not intended to provide advice on personal medical matters, nor is it intended to be a substitute for consultation.