And It's About Time There Was Some Support For Cushing's!
15 Oct 1999 Featured Article by Troya Renee Yoder, used with permission as originally posted on Suite 101.com, Pituitary Disorders
First described by the physician, Harvey Cushing, in 1912, Cushing’s syndrome (sometimes called hypercortisolism) refers to a disorder in which the body suffers from prolonged exposure to high levels of the stress hormone, cortisol. Because of the gradual nature of the disease, the time between the onset of symptoms and the diagnosis of Cushing’s is often long and frustrating.
In order to understand how Cushing’s syndrome arises, it is necessary to briefly examine the cortisol pathway. First, the hypothalamus secretes corticotropin releasing hormone (CRH). CRH stimulates the pituitary gland to secrete ACTH, which causes the adrenal glands to release cortisol into the bloodstream. A biologic feedback loop exists in which the hypothalamus and pituitary release less CRH and ACTH when cortisol reaches adequate levels in the bloodstream. However, there are a number of situations that may upset the cortisol feedback loop, leading to excess cortisol secretion, and hence, Cushing’s syndrome.
The symptoms of Cushing’s are many, and no two patients are affected the same. Some of the most common include:
There are four different possible causes of Cushing’s: a pituitary tumor, an adrenal tumor, a tumor outside the pituitary or adrenal glands, and exposure to certain medications. It is very important to determine the source of Cushing’s (Part 2 in this series will address laboratory tests used to differentiate between the possible causes of Cushing’s).
The most common cause of Cushing’s is a benign pituitary tumor, which secretes adrenocorticotrophic hormone (ACTH). This type of Cushing’s is called “Cushing’s Disease” and is five times more common in women than men.
Some benign or cancerous tumors outside of the pituitary and adrenal glands secrete excess ACTH, causing Ectopic Cushing’s syndrome. The most common types of tumors are oat cell tumors of the lung, thymomas, pancreatic islet cell tumors and medullary carcinomas of the thyroid. Ectopic Cushing’s syndrome occurs in 1 out of 100,000 people and is three times more common in men than women.
The treatment of other diseases such as asthma and rheumatoid arthritis with glucocorticoid hormones can cause exogenous Cushing’s syndrome, or Cushing’s syndrome-like symptoms.
Pseudo Cushing’s describes conditions such as depression, alcoholism, severe stress, and panic disorders that may cause some of the symptoms and altered laboratory findings of consistent with Cushing’s syndrome.