Causes of Cushing's Disease

A diagnosis of Cushing's disease can evoke a mix of emotions. While it may be the long-awaited answer regarding the cause your symptoms, it can also be a source of anxiety as you think about navigating through the uncertainties that lie ahead.

The first questions that may arise are, "Why me?" and "What exactly causes Cushing's disease?" In this article, we delve into the origins of Cushing's disease and address common questions that patients may have about this rare condition.

The main cause of Cushing’s disease is a pituitary adenoma, which is a non-cancerous tumor located in the pituitary gland. The pituitary gland is a small, pea-sized structure located at the base of the brain and is responsible for producing and regulating various hormones in the body.

In Cushing's disease, the pituitary adenoma produces excessive amounts of adrenocorticotropic hormone (ACTH). ACTH stimulates the adrenal glands located atop the kidneys, prompting them to produce cortisol, commonly known as the "stress hormone".

Maintaining appropriate ACTH levels helps to regulate the body's stress response. However, when ACTH levels become elevated, it can result in uncontrolled overproduction of cortisol, leading to a persistent state of stress in the body and various symptoms such as weight gain, fatigue, and skin thinning.

Here is a breakdown of the key components related to Cushing's disease:

• Pituitary gland: The pituitary gland is a 6 to 8 mm structure located at the base of the brain, just below the hypothalamus. It is often referred to as the "master gland" because it produces and regulates several hormones that control various bodily functions, including growth, reproduction, metabolism, and stress response.

• Adenoma: A pituitary adenoma is a benign (non-cancerous) tumor that originates from the cells of the pituitary gland. Adenomas can develop in any part of the pituitary gland and may produce excess hormones, leading to hormonal imbalances and associated symptoms. In the case of Cushing's disease, the adenoma secretes excessive amounts of ACTH.

• ACTH: Adrenocorticotropic hormone (ACTH) is produced by the front (anterior) part of the pituitary gland. Its primary function is to stimulate the adrenal glands to produce cortisol, a steroid hormone that helps regulate metabolism, immune function, and stress response. In Cushing's disease, the pituitary adenoma produces an excess of ACTH, leading to increased cortisol production by the adrenal glands.

• Adrenal Glands: Also known as the suprarenal glands, are small, triangular-shaped glands located on top of the kidneys. They secrete various hormones, one of which is cortisol. In response to excess ACTH, the adrenal glands release more cortisol than the body needs.

Most pituitary tumors, including those causing Cushing's disease, typically develop sporadically without any known specific risk factors or genetic predispositions. Ongoing research aims to deepen our understanding of the mechanisms behind the development of Cushing's disease and pituitary adenomas in general.

This is a very common question asked by those concerned about Cushing’s disease. However, Cushing’s disease is not actually caused by a deficiency. Rather, the condition is a result of a hormonally overactive pituitary gland, specifically caused by the presence of the adenoma.

Cushing's disease is not linked to a deficiency in any hormone, vitamin, or any other substance. Instead, it stems from the overproduction of cortisol, resulting in the diverse symptoms associated with the condition. The underlying cause of Cushing's disease is the pituitary adenoma itself, which triggers excess cortisol production, rather than a deficiency in any hormone or factor.

Cushing's disease is not triggered by stress. Rather, it is a medical condition resulting from a non-cancerous pituitary adenoma, a tumor located in the pituitary gland. Although stress can prompt the body to release cortisol as part of its natural "fight or flight" response, chronic or prolonged stress does not directly induce Cushing's disease.

Cushing's disease predominantly affects adults, usually between the ages of 20 and 50 years. This hormonal disorder is more commonly observed in women, with approximately three times as many affected compared to men. While estimates of its prevalence vary among different sources, approximately 10 to 15 individuals per million are affected by the disease.

While Cushing's disease is excess cortisol due to a pituitary adenoma, Cushing's syndrome is a more general term referring to excess cortisol from any cause. Prolonged use of corticosteroid medications like prednisone, hydrocortisone, or dexamethasone, often prescribed for conditions such as severe asthma or rheumatoid arthritis, is a common cause.

There are additional potential causes, such as tumors in the adrenal glands directly producing cortisol or ACTH-secreting tumors elsewhere in the body, known as ectopic Cushing's syndrome. During a comprehensive evaluation for suspected Cushing's disease, your doctor will conduct tests to rule out these alternative possibilities. Providing information about any current or past medication use is crucial to aid in the diagnostic process.

• Cushing's disease is caused by a specific type of pituitary adenoma, a non-cancerous tumor, located in the pituitary gland.
• The exact cause of pituitary adenomas that lead to Cushing's disease is not always clear, but some cases may be linked to genetic mutations or other factors that contribute to abnormal cell growth in the pituitary gland.
• Cushing's disease is relatively rare and typically affects adults, most commonly women between the ages of 20 and 50.
• Early diagnosis and appropriate treatment are crucial for managing the condition effectively.

• Endocrine Society
• Pituitary Foundation
• Urology Care Foundation
• National Adrenal Diseases Foundation