Cushing's Disease: Let's Untangle It

Cushing's disease affects many different parts of your body

Cushing's disease is caused by a tumor on the pituitary gland, located at the base of your brain. This tumor is usually benign, meaning not cancerous. Through a chain of hormonal events that will be described throughout this site, the pituitary tumor results in high levels of cortisol, a naturally occurring hormone commonly known as the "stress hormone." It's called this because cortisol is released during times of stress.

Too much cortisol in your blood is what causes the symptoms of Cushing's disease. This can have long-term effects on your overall health, appearance, energy, well-being, and quality of life.

It's important to note that Cushing's disease is not the same as Cushing's syndrome. You can learn about the difference here.

Breaking down the numbers of Cushing's disease

Rare* but serious, has an incidence of 1.2 to 2.4 cases per million people per year

3 times more likely to develop in women, most commonly between ages 30-60

It may take 5-7 years before a diagnosis of Cushing's disease is made

*The US Food and Drug Administration defines a rare disease as a condition that affects fewer than 200,000 people.

We know. It's complicated. But the main thing to remember is that someone with Cushing's disease has too much cortisol being produced. This extra cortisol over a period of time causes many symptoms throughout the body.

Recognize the symptoms: What does your cushing's disease look like?

I'm just physically unable to do many things I should be able to.

Cushing's disease has many different symptoms. Why so many? It has to do with high levels of cortisol, and all the different roles cortisol plays in the body. We'll get into those details later. Cushing's disease symptoms can differ from person to person. Rapid weight gain in the stomach area and the face is usually the first sign of Cushing's disease. However, you may experience one or more of the following symptoms to varying degrees.

What a person with Cushing's might look like

A person with Cushing's disease might have one or the following symptoms:

Depression, anxiety, problems with memory and attention—a general mind "fog"
Buffalo hump, a fat pad between shoulders
Unexplained osteoporosis or brittle bones
High blood pressure
Diabetes
Thinning of skin
Muscle weakness
"Moon" face
Oily skin or acne
Red cheeks
Hirsutism, or irregular hair growth
Unusual weight gain above collarbone
Unexplained weight gain in stomach area
Reddish-purple stretch marks
Poor healing of wounds
Easy bruising of skin

Cushing's disease can make it hard to remember things. Making a list of your symptoms can help you share the full story with your doctor. It may also be helpful to show your doctor pictures of how you looked before your symptoms appeared. Having a hard time dealing with the mental side of Cushing's disease? Visit our Tips for Coping.

Role of cortisol: The stress hormone

My cortisol levels were too high. I couldn't keep my anxiety under control. Sometimes I would sleep for 20 minutes, sometimes 2 days.

To better understand Cushing's disease, it helps to understand cortisol. A naturally occurring hormone, cortisol is often referred to as the stress hormone. Under normal circumstances, it is released in times of stress and illness. Cortisol also helps to maintain many systems in the body, such as blood pressure, blood sugar levels, bone formation, and the sleep/wake cycle. Cortisol plays an important role in how the body uses fats, proteins, and carbohydrates.

What happens when there is too much cortisol?

Uncontrolled blood pressure
High blood sugar levels (diabetes)
Fats, protein, carbohydrates not processed correctly
Bones become brittle
Disrupted sleep/wake cycle (insomnia)
Constant feeling of anxiety, stress

When cortisol levels are too high over a period of time, things like blood pressure and weight start to become unregulated. Food may not be processed correctly, and diabetes can develop. You can feel stressed, and have a hard time sleeping. Your moods may even be affected, and you may become frustrated or irritated.

Cushing's disease is outward anger. You tend to take it out on those close to you.

Where does all of this cortisol come from?

Cortisol is made in the adrenal glands, which are located on the top of each kidney. Cortisol is released via a pathway called the hypothalamic-pituitary-adrenal axis, or HPA axis. When the body needs cortisol, the hypothalamus, which is located in the brain, triggers the pituitary gland to release a hormone called ACTH (AdrenoCorticoTropic Hormone).

Next, ACTH signals the adrenal glands on the kidneys to release cortisol. Normally, the hypothalamus and pituitary gland can sense when there is enough cortisol in your blood. They send a signal to the adrenal glands to turn off until more cortisol is needed.

In Cushing's disease, the cortisol pathway is disrupted by a pituitary gland tumor

This causes too much ACTH to be released, which in turn leads to a constant release of cortisol by the adrenal glands. It is this high level of cortisol in your blood that causes the symptoms of Cushing's disease.

Cortisol pathway

The pituitary gland releases ACTH (adrenocorticotropic hormone) when signaled by the brain.

ACTH tells the adrenal glands on the kidneys to make cortisol. Normally, your body can sense when there is enough cortisol in the blood, and ACTH production stops. This feedback keeps the cortisol levels normal.

Cortisol levels remain high in Cushing's disease. This is caused by a tumor on the pituitary gland causing the release of too much ACTH. This ACTH tells the adrenal glands to keep making cortisol. It is these high levels of cortisol that cause the symptoms of Cushing's disease.

Cushing's disease and Cushing's syndrome: They are not the same

Cushing's syndrome is a broader term used to describe a group of symptoms caused by high levels of cortisol circulating in the body due to many different reasons.

Cushing's disease is the most common form of Cushing's syndrome, and a little more specific. The symptoms in this case are caused by high levels of cortisol due to a pituitary tumor.

I was frustrated but determined to try and solve the problem. I would try to stay positive and smile on the outside, but I was a mess on the inside.

If symptoms are the same, why does it matter?

It is important to know the exact cause of your high cortisol levels so your doctor can treat it properly. There are two categories of Cushing's syndrome, ACTH-dependent and ACTH-independent. Cushing's disease falls under the ACTH-dependent category of Cushing's syndrome, since the tumor on the pituitary gland causes it to release too much ACTH.

Cushing's syndrome can also be due to causes outside of the body, such as taking steroid medicines (that act like cortisol) for a long period of time.

Four most common causes of cushing's syndrome

ACTH-Dependent	ACTH-Independent
Cushing's Disease Pituitary tumor causes excess ACTH to be released, which results in high levels of cortisol. Cushing's disease makes up almost 80% of Cushing's syndrome cases.	Ectopic ACTH Syndrome Excess cortisol is due to an ACTH-producing tumor somewhere other than the pituitary gland (for example, in the lungs).	Adrenal Adenoma Excess cortisol is due to a non-cancerous adrenal gland tumor (located in the kidneys).	Adrenal Carcinoma Excess cortisol is due to a cancerous adrenal gland tumor.

ACTH-Dependent

ACTH-Independent

Cushing's Disease

Pituitary tumor causes excess ACTH to be released, which results in high levels of cortisol. Cushing's disease makes up almost 80% of Cushing's syndrome cases.

Ectopic ACTH Syndrome

Excess cortisol is due to an ACTH-producing tumor somewhere other than the pituitary gland (for example, in the lungs).

Adrenal Adenoma

Excess cortisol is due to a non-cancerous adrenal gland tumor (located in the kidneys).

Adrenal Carcinoma

Excess cortisol is due to a cancerous adrenal gland tumor.

These are the most common causes of Cushing's syndrome. There is another ACTH-dependent cause that is known as ectopic CRH. This is very rare. It occurs when a tumor causes the hypothalamus to produce too much corticotropin-releasing hormone (CRH), which causes the pituitary gland to release too much ACTH.

So many unfamiliar words! Let us help

Adenoma: a non-cancerous, or benign tumor

ACTH: adrenocorticotropic hormone

Ectopic: when something, like a tumor, is in an abnormal place

Carcinoma: a cancerous tumor

Diagnosing Cushing's disease is not easy. Why? Well, it's rare, symptoms can be confused with other conditions, and no two people with Cushing's disease are alike. For these reasons, it may take some time to get diagnosed.

But don't give up until you find answers, because it is important to get diagnosed as soon as possible. If the high cortisol is not treated, high blood pressure or other heart problems, diabetes, and thinning bones (called osteoporosis) may get worse over time. The earlier you are diagnosed and treated, the more likely your quality of life will improve.

Finding an endocrinologist that specializes in pituitary diseases is so important when looking for answers about Cushing's disease. Need help finding one? Follow me.

Diagnosing Cushing's Disease ›