Commonly asked questions about Cushing’s syndrome and Cushing’s disease

Below, you'll find answers to questions on the following topics:

  • Definition and causes of Cushing’s syndrome and Cushing’s disease
  • Signs and symptoms
  • Diagnosis
  • Complications

Commonly Asked Questions About Cushing's Disease

Q&As on the definitions and causes of Cushing's syndrome and Cushing's disease

Q:What is Cushing's syndrome?
A:Cushing's syndrome is the collective name for a variety of health problems that develop if there is too much cortisol circulating in the body for too long.1
Q:What causes Cushing's syndrome?
A:In the majority of cases, Cushing's syndrome develops when a person has been regularly taking more glucocorticoid-containing medicine than his or her body can handle. But in the other cases, Cushing's syndrome is usually due to a tumor causing overproduction of a glucocorticoid called cortisol.1,2
Q:Are tumors that cause Cushing's syndrome usually cancerous?
A:No. In the majority of people, the tumor is benign (noncancerous).3
Q:Where is the tumor that causes Cushing's syndrome located?
A:In more than 2 out of 3 people, the tumor is in the pituitary gland. This is called Cushing's disease. However, in some cases the tumor is in the adrenal gland or somewhere else in the body.1
Q:How does a pituitary tumor cause Cushing's disease?
A:A tumor in the pituitary gland produces excess amounts of a hormone called adrenocorticotropic hormone (ACTH). The normal cortisol feedback mechanism is disturbed, which signals the adrenal glands to produce too much cortisol. Excess cortisol is what causes the signs and symptoms of Cushing's disease.
Q:How does an adrenal tumor cause Cushing's syndrome?
A:An adrenal tumor releases excess cortisol, irrespective of ACTH production.4
Q:What is the difference between Cushing's syndrome and Cushing's disease?
A:Cushing's disease is when Cushing's syndrome is caused by a pituitary tumor.4
Q:What is "ectopic Cushing's syndrome"?
A:Ectopic Cushing's syndrome is caused by a nonpituitary tumor that produces excess ACTH.4

Q&As on signs and symptoms of Cushing's disease

Q:What are some of the signs that indicate a person might have Cushing's disease?
A:Cushing's disease and Cushing's syndrome have the same signs. Some of the most visible signs include a round ("moon") face, purplish streaks across the skin, an unusual buildup of fatty tissue in the abdominal area and/or between the shoulder blades ("buffalo hump"), easy bruising, and excess facial/body hair growth "hirsutism" in women.1,5
Q:Do these physical changes happen to everyone with Cushing's disease?
A:No. The signs and symptoms of Cushing's can vary from person to person.1
Q:What are some of the other signs and symptoms of Cushing's disease?
A:Obesity, reduced sex drive, a red face, high blood pressure, weakness, diabetes and other glucose metabolism disorders, weak bones, kidney stones, thin skin, memory problems, and depression and other mood disorders are some of the other signs and symptoms.2,6

Q&As on complications from Cushing's disease and Cushing's syndrome

Q:What are complications caused by Cushing's disease?
A:Cushing's disease and Cushing's syndrome cause the same complications, including several that can put the heart at risk. These include high blood pressure, high cholesterol, diabetes, and obesity. Other complications include osteoporosis and psychological and mental changes.2

Q&As on diagnosing Cushing's disease and Cushing's syndrome

Q:How is Cushing's syndrome diagnosed?
A:A series of tests are performed to first diagnose high levels of cortisol, then to find out what is causing this to happen. It can take a long time for many people with Cushing's disease to be accurately diagnosed since it is easy to mistake for other conditions. Cushing's disease causes many conditions, such as diabetes and osteoporosis, which are commonly diagnosed and treated as the primary condition. If Cushing's disease is the underlying cause of another condition, it often requires more time and effort to diagnose.1,5 When there are multiple conditions or other signs and symptoms, Cushing's disease should be suspected.
Q:Why is Cushing's disease often misdiagnosed?
A:The signs and symptoms of Cushing's disease vary in each patient. Also, many signs and symptoms are the same as those seen with other, more common conditions. For this reason, Cushing's disease may be diagnosed as another condition at first.1
Q:What tests are used to diagnose Cushing's syndrome?
A:Tests are performed to measure cortisol levels in the urine (urine-free cortisol test), saliva (late-night salivary cortisol test), and/or blood (late-night plasma cortisol test and dexamethasone suppression tests). Once the doctor knows that the level of cortisol is too high, other tests are used to determine if the cause is Cushing's syndrome, Cushing's disease, or something else.1,5
Q:What tests are used to diagnose Cushing's disease?
A:Once you have been diagnosed with Cushing's syndrome, your doctor will perform tests to determine if you have Cushing's disease. The doctor uses a blood test to measure ACTH levels, an MRI and/or CT scan, and other tests to find out if Cushing's syndrome is caused by a pituitary tumor that is producing too much ACTH (Cushing's disease), or a tumor in another part of the body that is producing too much ACTH or cortisol.1,2
Q:Do you have to go to the hospital for these tests?
A:Samples of urine and saliva can be gathered at home and are then tested in a lab. For the blood test, one or more doses of dexamethasone are taken at home, then a blood sample is taken a few hours later at the doctor's office.5 For the late-night plasma cortisol test, a blood sample is obtained at night while sleeping in a hospital. The blood sample is then given to a lab for testing.2
Q:What is a corticotropin-releasing hormone (CRH) stimulation test?
A:A CRH stimulation test involves giving an intravenous injection of CRH. First, a blood test is performed to check ACTH and serum cortisol levels. Then, the CRH injection is given. After that, blood tests are repeated several times to recheck ACTH and serum cortisol levels. If these levels are higher, this helps to confirm that there is a pituitary tumor (Cushing's disease).7
Q:What is a bilateral inferior petrosal sinus sample (IPSS) test?
A:An IPSS test can be used to determine if an ACTH-producing tumor is in the pituitary gland (Cushing's disease) or elsewhere.2

References: 1. Newell-Price J, Bertagna X, Grossman AB, Nieman LK. Cushing’s syndrome. Lancet. 2006;367:1605-1617. 2. Arnaldi G, Angeli A, Atkinson AB, et al. Diagnosis and complications of Cushing’s syndrome: a consensus statement. J Clin Endocrinol Metab. 2003;88:5593-5602. 3. Pathophysiology of disease: disorders of the hypothalamus & pituitary gland. Access Medicine Web site. http://www.accessmedicine.com/content.aspx?aID=2090603. Accessed July 30, 2009. 4. Biller BMK, Grossman AB, Stewart PM, et al. Treatment of adrenocorticotropin-dependent Cushing’s syndrome: a consensus statement. J Clin Endocrinol Metab. 2008;93:2454-2462. 5. The Hormone Foundation’s patient guide to the diagnosis of Cushing’s syndrome. The Hormone Foundation. http://www.hormone.org/resources/patient_guides/upload/mgmt-cushings-syndrome-070609.pdf. Accessed August 4, 2009. 6. Nieman LK, Ilias I. Evaluation and treatment of Cushing’s syndrome. Am J Med. 2005;118:1340-1346. 7. Lin DD, Loughlin KR. Diagnosis and management of surgical adrenal diseases. J Urol. 2005;66:476-483.