Cushing’s disease is a rare condition in which the pituitary gland releases excess adrenocorticotropic hormone (ACTH). ACTH is responsible for prompting the adrenal glands to produce cortisol. Cortisol is a hormone that helps regulate various processes in the body, like metabolism and the body’s response to stress. Cortisol is necessary in certain amounts but when the body produces too much, it can cause complications to one’s health. When the body produces too much ACTH, the result is that this excess in ACTH signals the body to make more.
Cushing’s disease is a form of Cushing’s syndrome. Cushing’s syndrome is the general state of too much cortisol production. Cushing’s disease is characterized by elevated cortisol levels as a direct result of the pituitary gland producing too much ACTH due to the presence of a tumor.
Causes
Cushing’s disease develops as a result of a tumor in the pituitary gland called a pituitary adenoma. An adenoma is almost always benign or noncancerous; however, these growths can cause physiological changes in the pituitary gland. In this case, the pituitary tumor stimulates the pituitary gland and causes an overproduction of adrenocorticotropic hormone (ACTH).
Symptoms
Not every individual diagnosed with this disease will experience the same symptoms. Symptoms, and their severity, will vary from person to person.
In general, symptoms may include:
- Obesity above the waist, while maintaining thin arms and legs
- A round, fuller face
- Excess fat on the back of the neck
- Acne
- Skin that bruises easily
- Mood changes, like depression or anxiety
- Weakened bones
- Bone pain
- Weakened muscles
- Stretch marks (striae) on the abdomen, thighs, and/or breasts
- In children, slow growth rate accompanied by obesity
Women may experience:
- Excess hair growth on the stomach and face
- Irregular menstrual cycle or one that stops
Men may experience:
- Impotence
- Decreased libido
What to expect at your appointment
During your appointment, your doctor will ask you about your symptoms and your medical history, including any current medications you’re taking. If your doctor suspects Cushing’s disease based on your symptoms, they will begin the diagnostic process. In order to diagnose the disease, your doctor will prescribe multiple testing techniques that may include seeing an endocrinologist and other specialists.
The first step toward diagnosing Cushing’s disease involves identifying elevated levels of cortisol in the body, or Cushing’s syndrome. Cushing’s syndrome is the general term used to describe elevated cortisol in the body.
Some of the tests used to measure the amount of cortisol in the body include:
- Urinary free cortisol test, which is done using a urine sample
- Dexamethasone suppression test (DST), which can be done overnight or over the course of two days
- Salivary cortisol test, which can be done early in the morning or late at night
If testing shows high levels of cortisol, your doctor will proceed with further testing in order to diagnose Cushing’s disease or another form of Cushing’s syndrome.
Diagnostic tests used to diagnose this disease include:
- Blood test to measure the amount of adrenocorticotropic hormone (ACTH) in the blood
- Imaging tests, such as an MRI or a CT scan, to locate a tumor
- Corticotropin-releasing hormone (CRH) stimulation test
Treatments
Non-surgical treatments
Cushing’s disease is somewhat unusual in that surgery, not medication, is usually the first line of treatment. Initial treatment for this disease aims to remove the pituitary tumor in order to lower the amount of cortisol in the body. Radiation may be necessary if the entire tumor cannot be removed. If the tumor does not respond to surgical treatment or radiation, special medication may be prescribed that stops the production of cortisol.
Surgical treatment and post-treatment
Surgical removal of the pituitary tumor is the only treatment that provides a long-term solution or cure for the disease. If the tumor is not fully removed, radiation treatment may be necessary in order to shrink the remaining piece of the tumor.
After surgery, the pituitary gland will need time to start working again and return to its normal capacities. During this time, some individuals may be prescribed cortisol replacement treatments until the pituitary gland is able to produce ACTH on its own. If surgery is unsuccessful in treating the symptoms, patients may be prescribed medication that inhibits the production of cortisol.
In some individuals, the tumor does not respond to surgical intervention, radiation, or medications that prevent excess cortisol production. If this occurs, surgical intervention to remove the adrenal glands may be recommended in order to inhibit the body from producing cortisol altogether.
Recovery can take as long as one to two years. This is because this condition affects every system in the body.
Outlook and prognosis
In order to successfully treat Cushing's disease, it is important to seek care from a team of experts who are highly experienced in the diagnosis and treatment of this condition. If left untreated it can lead to serious health complications, long-term health complications like hypertension, and even premature death. Removal of the entire tumor may result in a full recovery. However, there is a risk that the tumor can return; therefore, careful monitoring is necessary.
The MedStar Pituitary Center, based at MedStar Washington Hospital Center, is the only multi-disciplinary pituitary tumor program in the Washington, D.C., area. We are dedicated to providing a comprehensive approach to the diagnosis and treatment of Cushing’s disease.
"With various key specialists interacting closely, it allows for rapid exchange of thoughts and ideas, leading to better care for patients."
—Dr. Susmeeta Tewari Sharma,
Director of Pituitary Endocrinology at the MedStar Pituitary Center
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