Cushing’s syndrome is a hormonal condition. It happens when a person’s cortisol levels are too high. It can have severe and wide-ranging effects on the body.
It often results from using medications that lead to high levels of cortisol in the body, but other causes include a benign or cancerous tumor.
People sometimes confuse Cushing’s syndrome with Cushing’s disease. The two are related but not the same.
In Cushing’s disease and Cushing’s syndrome, a number of factors can lead to high levels of the hormone cortisol. This, in turn, leads to a number of symptoms.
In Cushing syndrome, too much cortisol in the body results in a range of symptoms.
One cause of Cushing’s syndrome is Cushing’s disease. This is a rare condition that happens when a pituitary adenoma — a non-cancerous tumor in the pituitary gland — releases high levels of a hormone known as adrenocorticotropic hormone (ACTH).
These high levels of ACTH trigger high levels of cortisol, resulting in a range of symptoms.
Sometimes, the tumors form because of certain genetic changes or syndromes. Most of the time, it is unclear why it happens.
Genetics Home Reference note that it usually appears in adults between the ages of 20 and 50 years, but it can affect children, too.
Statistics suggest it affects about 10 to 15 people per million globally.
Seven out of 10 people with Cushing’s disease are women.
Cushing’s syndrome includes Cushing’s disease, but it most commonly happens when the use of steroid medications affects hormone levels.
Apart from those with Cushing’s disease, people who are at risk of developing Cushing’s syndrome include those who:
take large doses of steroid medication for another illness, such as asthma
have a tumor in the adrenal gland
have cancerous tumors that produce ACTH, for example, certain lung cancers
All of these factors can lead to a high level of cortisol in the body.
Less commonly, tumors develop in other organs that release ACTH, leading to similar symptoms.
When Cushing’s syndrome happens for reasons that are not drug-linked, 70 percent of these cases will be due to Cushing’s disease, according to the American Association of Neurological Surgeons (AANS).
Pseudo-Cushing’s syndrome is when symptoms are similar to those of Cushing’s syndrome, but further tests show that the syndrome is not present. Common causes include consuming too much alcohol, obesity, persistently high blood glucose levels, pregnancy, and depression.
How does it happen?
The pituitary gland produces hormones. If a tumor develops on this gland, Cushing’s symptoms may result.
The body system that controls hormone production is the endocrine system.
Within this system, the glands work together and produce different types of hormones.
The hormones that one gland produces can directly affect the hormone production of other glands.
These glands include the adrenal glands, pituitary gland, thyroid gland, parathyroid glands, pancreas, ovaries, and testicles.
The adrenal glands are just above the kidneys. They produce cortisol, along with other hormones. Cortisol is the primary stress hormone, and it is the major natural glucocorticoid (GC) in humans.
Cortisol helps to regulate how the body turns proteins, carbohydrates, and fat from food into energy.
It also helps to control blood pressure and blood glucose levels and to maintain cardiovascular function. It can suppress the immune system, and it affects how the body responds to stress.
When cortisol levels are persistently high, Cushing’s syndrome can result.
Genetic factors may play a role in some cases, but Cushing’s syndrome and Cushing’s disease do not appear to run in families.
There are two types of Cushing’s syndrome.
Exogenous Cushing’s syndrome
Exogenous Cushing’s syndrome is when the cause comes from something outside the body’s function.
It often results from long-term, high-dose usage of corticosteroid drugs, also known as glucocorticoids. These are similar to cortisol.
People with rheumatoid arthritis, lupus, asthma, and recipients of an organ transplant may need high doses of these drugs.
Injectable corticosteroids, a treatment for joint pain, back pain and bursitis, can also lead to Cushing’s syndrome.
Steroid medications that do not appear to increase the risk of Cushing’s syndrome are:
steroid creams, a treatment option for eczema
inhaled steroids, a treatment for asthma
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) note that over 10 million people in the United States use glucocorticoid medications each year, but it remains unclear how many develop the symptoms of Cushing’s syndrome.
Endogenous Cushing’s syndrome
Endogenous Cushing’s syndrome is when the cause comes from inside the body, for example, when the adrenal glands produce too much cortisol.
Cushing’s disease is an example of this.
Similar symptoms can also result from adrenal gland tumors or from a benign or malignant tumor in the pancreas, thyroid, thymus gland, or lung.