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Cushing’s disease
Definition
Cushing’s disease is a condition in which the pituitary gland releases too much adrenocorticotropic hormone (ACTH). The pituitary gland is an organ of the endocrine system.
Cushing's disease is a form of Cushing syndrome.
Alternative Names
Pituitary Cushing's disease
Causes
Cushing's disease is caused by a tumor or excess growth (hyperplasia) of the pituitary gland. This gland is located at the base of the brain.
People with Cushing's disease have too much ACTH. ACTH stimulates the production and release of cortisol, a stress hormone. Too much ACTH means too much cortisol.
Cortisol is normally released during stressful situations. It controls the body's use of carbohydrates, fats, and proteins and also helps reduce the immune system's response to swelling (inflammation).
Symptoms
Symptoms usually include:
- Upper body obesity (above the waist) and thin arms and legs
- Round, red, full face (moon face)
- Slow growth rate in children
Skin changes that are often seen:
- Acne or skin infections
- Purple marks (1/2 inch or more wide), called striae, on the skin of the abdomen, thighs, and breasts
- Thin skin with easy bruising
Muscle and bone changes include:
- Backache, which occurs with routine activities
- Bone pain or tenderness
- Collection of fat between the shoulders (buffalo hump)
- Thinning of the bones, which leads to rib and spine fractures
- Weak muscles
Women often have:
- Excess hair growth on the face, neck, chest, abdomen, and thighs
- Menstrual cycle that becomes irregular or stops
Men may have:
- Decreased or no desire for sex
- Impotence
Other symptoms that may occur include:
- Mental changes, such as depression, anxiety, or changes in behavior
- Fatigue
- Headache
- Increased thirst and urination
Exams and Tests
Tests are done to confirm there is too much cortisol in the body, then to determine the cause.
These tests confirm too much cortisol:
- 24-hour urine cortisol
- Dexamethasone suppression test (low dose)
These tests determine cause:
- Blood ACTH level
- Brain MRI
- Corticotropin-releasing hormone test, which acts on the pituitary gland to cause the release of ACTH
- Dexamethasone suppression test (high dose)
- Petrosal sinus sampling - measures ACTH levels in the veins that drain the pituitary gland
Treatment
Treatment involves surgery to remove the pituitary tumor, if possible. After surgery, the pituitary may slowly start to work again and return to normal.
During the recovery process, you may need cortisol replacement treatments. Radiation treatment of the pituitary gland may also be used.
If the tumor does not respond to surgery or radiation, you may get medications to stop your body from making cortisol.
If these treatments are not successful, the adrenal glands may need to be removed to stop the high levels of cortisol from being produced.
Outlook (Prognosis)
Untreated, Cushing's disease can cause severe illness, even death. Removal of the tumor may lead to full recovery, but the tumor can grow back.
Possible Complications
- Compression fractures
- Diabetes
- High blood pressure
- Infections
- Kidney stones
- Psychosis
When to Contact a Medical Professional
Call your health care provider if you develop symptoms of Cushing's disease.
If you have had a pituitary tumor removed, call if you have signs of complications, including signs that the tumor has returned.
References
Stewart PM, Krone NP. The adrenal cortex. In: Kronenberg H, Melmed S, Polonsky K, Larsen PR, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 15.
Reviewed By: Nancy J. Rennert, MD, Chief of Endocrinology & Diabetes, Norwalk Hospital, Associate Clinical Professor of Medicine, Yale University School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
