An Overview of Cushing's Syndrome

Cushing’s syndrome is a rare disorder that occurs when the body is exposed to too much cortisol. Cortisol is naturally produced in the body. Cushing's syndrome can occur either because cortisol is being overproduced by the body or from the use of drugs that contain cortisol (corticosteroids drugs like prednisone).

About Cortisol

Cortisol is the body’s main stress hormone. Cortisol is secreted by the adrenal glands in response to the secretion of adrenocorticotropic hormone (ACTH) by the pituitary. One form of Cushing’s syndrome may be caused by an oversecretion of ACTH by the pituitary leading to an excess of cortisol.

Cortisol has several functions, including the regulation of inflammation and controlling how the body uses carbohydrates, fats, and proteins. Corticosteroids such as prednisone, which are often used to treat inflammatory conditions, mimic the effects of cortisol.

Causes of Cushing’s Syndrome

Some causes of Cushing's syndrome include:

Cushing’s Disease

Cushing's disease is one common cause of the Cushing's syndrome that occurs when the pituitary releases excess ACTH, leading to extra cortisol being made. This can result from a pituitary tumor or other growth.

Iatrogenic Cushing’s Syndrome

The use of high doses of steroid medications for a long time can cause this form of Cushing’s syndrome. Steroid drugs or corticosteroid drugs are used to treat many inflammatory conditions, including asthma, lupus, rheumatoid arthritis, and inflammatory bowel disease (IBD). In some cases, they’re prescribed at high doses and for a long period of time.

Adrenal Gland Tumor

Finally, another cause, though less common, is caused directly by a tumor on the adrenal glands. These types of tumors cause high levels of cortisol, independent of ACTH production from the pituitary gland. When the tumor is only in one adrenal gland, the excess amount of cortisol produced can cause the non-affected adrenal gland to begin to shrivel and shrink.

Symptoms

Signs and symptoms of Cushing’s syndrome can include the following:

• Acne
• Buffalo hump (extra fat deposited on the back of the neck)
• Elevated glucose levels
• Excessive thirst
• Fatigue
• Increased urination
• Headache
• High blood pressure
• Hirsutism (excessive hair growth)
• Menstrual changes
• Obesity around the trunk
• Psychological symptoms such as mood instability, depression, anxiety, panic attacks
• Round, full face (known as moon face)
• Skin changes
• Stretch marks on the abdomen, arms, breasts, buttocks, and thighs (also called striae)
• Weakness

There could be other signs and symptoms of this condition that are not covered above. It’s important to see a physician with any concerns about symptoms of Cushing's syndrome.

Diagnosis of Cushing's Syndrome

There are distinguishable physical characteristics, such as the round moon face and buffalo hump, that are typical among people with Cushing’s syndrome. If a physician suspects Cushing’s, after the routine history, physical exam, and basic blood work, they will order blood and urine tests to measure the amount of cortisol present in the body.

If those levels are high, the doctor may order a test called a dexamethasone suppression test. This is a test where an oral steroid called dexamethasone is given and blood and urine tests are taken again to measure cortisol and other adrenal hormones. More tests may be ordered if these initial tests come back with results that indicate Cushing’s syndrome might be a concern.

A physician may move to a more intensive testing procedure if the initial screening shows that this is necessary. If a tumor is suspected as the cause of Cushing’s, other tests that might be ordered include a CT scan or an MRI. While the testing can seem like a lot of work or inconvenient, it is important to follow up and complete all of the testings that the doctor orders.

Treatment

Cushing's syndrome is best treated by determining what is causing the high levels of cortisol and removing it.

Cushing’s Disease

Surgery is usually the first-line treatment for patients with Cushing's disease.

Removal of the pituitary tumor and sometimes the entire pituitary gland, through a procedure, called transsphenoidal resection (behind the nose) by a neurosurgeon is usually necessary. If the entire pituitary needs to be removed, supplements of cortisol, thyroid, and sex hormones will need to be given.

If surgery is contraindicated or the tumor cannot be removed, radiation therapy can be used to shrink the tumor. If the tumor is found to be malignant, chemotherapy or radiation may be prescribed to reduce the risk of reoccurrence. There are medical treatments available for treating Cushing's disease as well as its symptoms, including Signifor (pasireotide) and Korlym (mifepristone).

Iatrogenic Cushing’s Syndrome

If the syndrome is being caused by prescribed medication, it is best to begin to taper the medication down, supervised by a physician, to remove the excess steroid. It is important to slowly decrease the amount of corticosteroid taken over the course of weeks or even months. A different medication or dose may be found to be a more appropriate treatment for the underlying condition. It is important to follow instructions precisely, as steroids cannot be stopped suddenly, but must be slowly tapered down.

If the steroids can't be stopped, or if it is going to take a long time to stop them, other treatments might be given to manage some of the signs and symptoms of Cushing's syndrome. Some of the aspects of this syndrome that might need treatment with other medications and changes to the diet include high blood sugar and high cholesterol. Reducing the risk of fractures with medications used to treat osteoporosis might also be necessary. In the case of depression or anxiety, referral to a mental health specialist for treatment may also be effective.

A Word From Verywell

In the case of Cushing's disease, most people recover well after surgery. Some signs of the disease may continue after surgery, such as hypertension, but these can often be managed with medications. If surgery isn't possible, there are also medical treatments available that can decrease the effects of increased cortisol. 

Taking steroid medications presents the risk of developing Cushing's syndrome, but the goal is always to get patients off steroids as quickly and as safely as possible to lower this risk. Cushing's syndrome can be treated by lowering the number of steroids being taken, and by treating some of the signs and symptoms. The use of steroids and the potential risk versus the benefits should always be discussed with a physician