Cushing Disease
A pituitary tumor that drives excess cortisol
Quick Facts
- Type: Hormone (endocrine) disorder
- Cause: Pituitary tumor releasing ACTH
- Hormone involved: Cortisol (made by adrenal glands)
- Main treatment: Surgery to remove the tumor
Overview
Cushing disease is a hormone disorder caused by a tumor of the pituitary gland, a small gland at the base of the brain. The tumor releases too much of a hormone called ACTH, which signals the adrenal glands to produce excess cortisol. Cortisol is a vital stress hormone, but consistently high levels harm many parts of the body.
Cushing disease is the most common cause of naturally occurring Cushing syndrome, the broader term for the effects of too much cortisol. (Cushing syndrome can also result from other causes, such as long-term use of steroid medications or an adrenal tumor.) The pituitary tumor is usually small and benign, and treatment, most often surgery, can control the excess cortisol and reverse many symptoms.
Symptoms
Excess cortisol affects the body in many ways. Common signs include:
- Weight gain, especially around the abdomen and upper back, and a rounded face
- A fatty hump between the shoulders
- Thin, fragile skin that bruises easily and heals slowly
- Wide purple or pink stretch marks
- High blood pressure and high blood sugar
- Muscle weakness, especially in the upper arms and thighs
- Thinning bones (osteoporosis)
- Fatigue, mood changes, irritability, or depression
- Irregular periods in women and reduced sex drive
Causes
Cushing disease is caused specifically by a pituitary tumor (usually a benign adenoma) that produces excess ACTH. This drives the adrenal glands to make too much cortisol.
It is important to distinguish Cushing disease from the broader Cushing syndrome. Cushing syndrome can also be caused by long-term use of corticosteroid medications, an adrenal gland tumor, or, rarely, ACTH produced by a tumor elsewhere in the body. Identifying the exact cause is essential because the treatment differs.
Risk Factors
- Female sex, as Cushing disease is more common in women
- Adulthood, with most cases diagnosed in young to middle-aged adults
- Rare inherited conditions that increase the risk of pituitary tumors
Most cases occur without an identifiable inherited cause.
Diagnosis
Diagnosis usually begins by confirming that cortisol is genuinely high. Tests may include measuring cortisol in a 24-hour urine sample, late-night saliva cortisol, and a dexamethasone suppression test that checks whether a steroid pill lowers cortisol as it should.
If excess cortisol is confirmed, blood ACTH is measured to find the source. In Cushing disease, ACTH is inappropriately high because of the pituitary tumor. An MRI of the pituitary gland looks for the tumor, and a specialized blood-sampling procedure may be used to confirm the pituitary as the source when imaging is unclear.
Treatment
The goal is to bring cortisol levels back to normal and reverse the effects of the disease. Options include:
- Surgery: Removing the pituitary tumor, often through the nose (transsphenoidal surgery), is the usual first treatment and can cure the condition.
- Radiation therapy: Used when surgery does not fully control the disease or is not possible.
- Medications: Drugs that lower cortisol production or block its effects, used as additional or temporary treatment.
- Adrenal surgery: Rarely, removing the adrenal glands is considered when other treatments fail.
After successful treatment, people may temporarily need steroid replacement and ongoing monitoring while the body readjusts. Related problems such as high blood pressure, diabetes, and bone loss are also managed.
When to See a Doctor
See a doctor if you have a combination of symptoms such as central weight gain, a rounded face, easy bruising, purple stretch marks, muscle weakness, and new high blood pressure or high blood sugar, especially if these are worsening. These can point to excess cortisol.
Seek prompt medical care for sudden severe headache, sudden vision changes, severe weakness, or symptoms of very high blood sugar or very high blood pressure. If you take steroid medications, never stop them suddenly without medical guidance, as this can cause a dangerous drop in cortisol.
Frequently Asked Questions
What is the difference between Cushing disease and Cushing syndrome?
Cushing syndrome is the general term for the effects of too much cortisol from any cause. Cushing disease is one specific cause, a pituitary tumor that releases excess ACTH and drives high cortisol. It is the most common natural cause of Cushing syndrome.
What causes Cushing disease?
It is caused by a tumor of the pituitary gland, usually small and benign, that produces too much ACTH. This hormone signals the adrenal glands to make excess cortisol, which leads to the symptoms of the disease.
How is Cushing disease treated?
Surgery to remove the pituitary tumor is the usual first treatment and can cure the condition. Radiation therapy and medications that lower cortisol are used when surgery is not fully effective, along with care for related problems like high blood pressure and bone loss.
Can Cushing disease be cured?
Yes, often. Successful surgery to remove the pituitary tumor can normalize cortisol and reverse many symptoms over time. Some people need additional treatment, and ongoing monitoring is important because the condition can sometimes recur.
Why should steroid medications not be stopped suddenly?
Long-term steroid use can suppress the body's own cortisol production. Stopping suddenly can cause a dangerous drop in cortisol. Steroid doses should always be reduced gradually under medical guidance.
References
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Cushing's Syndrome.
- Mayo Clinic. Cushing syndrome — Symptoms and causes.
- The Endocrine Society.
- MedlinePlus, U.S. National Library of Medicine. Cushing disease.