Causes of Cushing’s Syndrome

Cushing’s syndrome—also referred to as hypercortisolism—is fairly rare. However, researchers have boiled down a few key causes of Cushing’s syndrome, which you’ll read about below.

The cause of Cushing’s syndrome boils down to: Your body is exposed to too much cortisol. There are a few ways that this over-exposure can happen, including taking certain medications and having a tumor on your pituitary gland or adrenal gland.

Can Taking Corticosteroids Cause Cushing’s Disease?
One particular type of medication can cause Cushing’s syndrome: corticosteroids. But rest assured: Not all steroid medications cause Cushing’s syndrome. It’s more common to develop Cushing’s syndrome from steroids you take in pill form or steroids you inject. Steroid creams and steroids you inhale are not common causes of Cushing’s syndrome.

Some steroid medications have the same effect as the hormone cortisol does when produced in your body. But as with an excessive production of cortisol in your body, taking too much corticosteroid medications can, over time, lead to Cushing’s syndrome.

It’s common for people with asthma, rheumatoid arthritis, and lupus to take corticosteroids. Prednisone (eg, Deltasone) is an example of a corticosteroid medication.

Other Cushing’s Disease Causes
Your body can over-produce cortisol or adrenocorticotropic hormone (ACTH). The pituitary gland secretes ACTH, which is in charge of stimulating the adrenal glands to produce cortisol, and the adrenal glands are responsible for releasing cortisol into the bloodstream.

Cortisol performs important tasks in your body, such as helping to maintain blood pressure and regulate how your body metabolizes proteins, fats, and carbohydrates, so it’s necessary for your body to maintain normal levels of it.

The following can cause excessive production of cortisol or ACTH, leading to Cushing’s syndrome.

  • Pituitary gland tumors: A benign (non-cancerous) tumor of the pituitary gland can secrete an excess amount of ACTH, which can cause Cushing’s syndrome. Also known as pituitary adenomas, benign tumors of the pituitary gland affect women 5 times more often than men.
  • Adrenal gland tumors: A tumor in one of your adrenal glands can lead to Cushing’s syndrome by causing too much cortisol to enter your bloodstream. Most of these tumors are non-cancerous (called adrenal adenomas).

    Cancerous adrenal tumors—called adrenocortical carcinomas—are relatively rare. These types of tumors typically cause extremely high levels of cortisol and very rapid development of symptoms.

  • Other tumors in the body: Certain tumors that develop outside the pituitary gland can also produce ACTH. When this happens, it’s known as ectopic ACTH syndrome. Ectopic means that something is in an abnormal place or position. In this case, only the pituitary gland should produce ACTH, so if there is a tumor producing ACTH and it isn’t located on the pituitary, it’s ectopic.

    It’s unusual to have a tumor that secretes ACTH outside the pituitary. These tumors are usually found in the pancreas, lungs, or thyroid, and they can be benign or malignant (cancerous).

    The most common forms of ACTH-producing tumors are small cell lung cancer, which accounts for about 13% of all lung cancer cases, and carcinoid tumors—small, slow-growing tumors that arise from hormone-producing cells in various parts of the body.

  • Familial Cushing’s syndrome: Although it’s rare, Cushing’s syndrome can develop from an inherited tendency to have tumors on one or more of your endocrine glands. Some inherited conditions, such as multiple endocrine neoplasia (MEN 1), can involve tumors that over-produce cortisol or ACTH, leading to Cushing’s syndrome.

If you think you could have Cushing’s syndrome or you have questions about the causes of Cushing’s syndrome, talk to your doctor immediately.

Written by | Reviewed by Daniel J. Toft MD, PhD, adapted from  http://www.endocrineweb.com/conditions/cushings-syndrome/cushings-syndrome-causes

Midnight Salivary Cortisol Versus Urinary Free and Midnight Serum Cortisol as Screening Tests for Cushing’s Syndrome

From PubMed

Gafni RI, Papanicolaou DA, Nieman LK.
Developmental Endocrinology Branch, National Institute of Child Health and Human Development, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892-1862, USA.

OBJECTIVE: There is currently no optimal test to screen for endogenous Cushing’s syndrome (CS) in children. Traditional 24-hour urine or midnight serum cortisol values may be difficult to obtain or elevated by venipuncture stress. We hypothesized that salivary cortisol measurement is a reliable way to screen for CS in children.

STUDY DESIGN: Sixty-seven children (5-17 years) were studied: 24 obese volunteers, 29 non-obese volunteers, and 14 children with CS. Saliva was obtained at 7:30 AM, bedtime, and midnight for measurement of free cortisol by radioimmunoassay.

RESULTS: Salivary cortisol was detectable in all morning and evening samples from patients with CS but was frequently undetectable in healthy children at bedtime (66%) and at midnight (90%). With cut points that excluded healthy children, a midnight salivary cortisol value of 7.5 nmol/L (0.27 microg/dL) identified 13 of 14 patients with CS, whereas a bedtime value >27.6 nmol/L (1 microg/dL) detected CS in 5 of 6 patients. The diagnostic accuracies of midnight salivary cortisol and urinary free cortisol per square meter were the same (93%).

CONCLUSION: Salivary cortisol measurement at bedtime or midnight rules out CS in nearly all cases. Nighttime salivary cortisol sampling is thus a simple, accurate way to screen for hypercortisolism in children. PMID: 10891818 [PubMed – indexed for MEDLINE]


THE PRINCIPLE RESEARCHER FOR SALIVARY CORTISOLS IS HERSHEL RAFF AT THE UNIVERSITY OF WISCONSIN. HE IS A RESEARCH SCIENTIST, NOT A DOCTOR. YOU CAN CONTACT HIM DIRECTLY FOR ORDERING INFO.

Salivary Cortisol: A Screening Technique

By: Dr. Hershel Raff

Cushing’s syndrome – endogenous hypercortisolism – is characterized by a loss of circadian rhythmicity. In normal patients, cortisol levels peak in the early morning hours and decrease to substantially lower levels at night. Rather than the normal decrease in late evening cortisol, patients with Cushing’s syndrome of any cause fail to decrease cortisol secretion in the late evening. Therefore, the measurement of elevated late evening cortisol is helpful in the diagnosis of Cushing’s syndrome. Obtaining a late night, unstressed plasma cortisol is virtually impossible in most clinical practices. Salivary cortisol is in equilibrium with the free, biologically active portion of cortisol in the plasma. Therefore, if one obtains a saliva sample in patients at bedtime in their homes under unstressed conditions, one can make the diagnosis of endogenous hypercortisolism.

A simple way to sample saliva is by using a Salivette made by the Sarstedt Company (Newton, NC). This device consists of a cotton tube and plastic tubes. The patient only has to chew the cotton tube for 2-3 minutes and place it in the plastic tube. The tube is then transported to our lab for analysis.

Late-evening salivary cortisol is not intended to replace the current standard screening test – measurement of a 24 hr urine free cortisol. However, the salivary cortisol test can be extremely useful for patients suspected of having intermittent Cushing’s syndrome. Due to the convenience of sample collection, the patient can sample saliva several evenings in a row. In fact, our clinical endocrinologists routinely order 2-3 consecutive late-evening salivary cortisol samples.


Our research (Raff H, Raff JL, Findling JW. 1998 LATE-NIGHT SALIVARY CORTISOL AS A SCREENING TEST FOR CUSHING’S SYNDROME. J Clin Endocrinol Metab. 83:2681-2686) has shown that the combination of late-evening salivary cortisol and urine free cortisol is very accurate in diagnosing Cushing’s syndrome in most patients. Doctors can obtain a kit by contacting ACL Client Services at 1-800-877-7016.

Editor’s Note: DR. HERSHEL RAFF, PH.D. IS A PROFESSOR OF MEDICINE AND PHYSIOLOGY AT THE MEDICAL COLLEGE OF WISCONSIN’S ENDOCRINE RESEARCH LABORATORY AT ST. LUKE’S MEDICAL CENTER IN MILWAUKEE, WISCONSIN.

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