What is Cushing’s Disease?

Cushing's disease is a disorder related to abnormal hormone production. In Cushing's disease, this is specifically due to the presence of a benign tumor found in the pituitary gland.

Many of these terms may sound unfamiliar. But not to worry. In this article, we provide an overview of Cushing's disease and common questions patients may have.

Cushing's disease is a condition characterized by the production of excess cortisol, commonly known as "stress hormone". A hormone is a chemical substance produced by glands in the body. Hormones act as messengers, traveling through the bloodstream to target cells or organs where they can exert specific effects on many biological processes.  

When a hormone is produced in excess, many body systems can be affected. In the context of Cushing's disease, a non-cancerous tumor called a pituitary adenoma produces excess adrenocorticotropic hormone (ACTH). This hormone stimulates the adrenal glands on top of the kidneys to produce cortisol.

Cortisol is a critical hormone with impacts on many processes including metabolism, blood pressure, the immune system, and blood sugar levels. Surplus cortisol production produces a diverse array of symptoms. This can include unexplained weight gain, particularly in the facial and abdominal regions, muscle weakness, and even alterations in mood.

Cushing's syndrome and Cushing's disease are both conditions caused by excess cortisol in the body. However, they have different underlying causes. While Cushing's disease is specifically caused by a pituitary tumor, Cushing's syndrome refers to any condition that can cause excess cortisol by the adrenal glands.

Cushing's syndrome can be caused by various factors, including:

• Long-term use of corticosteroid medications, such as prednisone, for conditions like asthma, rheumatoid arthritis, or lupus
• Adrenal gland tumors that produce cortisol
• Tumors located outside of the pituitary gland that produce excess ACTH, such as in the lungs or pancreas

Several diseases can mimic Cushing's syndrome, presenting similar symptoms such as weight gain, high blood pressure, and fatigue. These conditions include polycystic ovary syndrome (PCOS), metabolic syndrome, depression, alcoholism, and obesity. Blood tests to detect abnormally elevated cortisol levels can be used to assist in the diagnosis.

The trajectory of Cushing's disease can exhibit significant variability among individuals, influenced by various factors such as the pituitary tumor itself, and the person's general well-being and treatment response.

Generally, the symptoms of Cushing's disease tend to develop gradually over time as cortisol levels rise. Early symptoms may be subtle and nonspecific, making diagnosis challenging in some cases.

Common symptoms include weight gain, particularly in the abdomen, face, and neck, fatigue, muscle weakness, thinning of the skin, easy bruising, and changes in mood or cognition. These symptoms, especially in isolation, can be mistaken for other conditions.

Cushing's disease is relatively rare, affecting less than 10 to 15 individuals per million people. It predominantly affects adults, usually between the ages of 20 and 50 years. This disease is more commonly observed in women, impacting approximately three times as many women as men.

Cushing’s disease is considered a serious disease if it is not properly treated. In Cushing's disease, the leading cause of mortality is associated with its cardiovascular complications. 

Excess cortisol production can trigger elevated blood pressure, insulin resistance, and abnormal lipid levels, which can lead to hypertension, diabetes, and obesity. These conditions collectively increase the risk of cardiovascular disease such as a heart attack and stroke.

Additionally, untreated Cushing' disease can lead to osteoporosis, characterized by reduced bone density and heightened vulnerability to fractures. Elevated cortisol levels also result in long-term suppression of the immune system, diminishing the body's ability to fend off infections and increasing susceptibility to illnesses.

Furthermore, individuals may experience mood swings, anxiety, depression, and cognitive impairments, exerting profound psychological consequences that significantly influence emotional well-being and overall quality of life.

While both conditions can result in weight gain, Cushing's disease is characterized by specific signs such as the redistribution of weight to the face, neck, and abdomen, along with thinning limbs.

Skin changes, such as easy bruising and purple stretch marks, are more prominent in Cushing's disease. Additionally, individuals with Cushing's disease might exhibit related symptoms like muscle weakness, fatigue, and mood fluctuations due to excess cortisol production.

Conversely, obesity typically lacks these distinctive physical features and is often associated with a more gradual weight gain pattern. Accurate differentiation often requires a comprehensive evaluation by healthcare professionals, involving medical history, physical examinations, and diagnostic tests like cortisol level assessments.

• Cushing's disease arises from the presence of a pituitary adenoma.
• Three signs of Cushing's disease include weight gain, muscle weakness, and fatigue.
• Left untreated, Cushing's disease is regarded as a serious medical condition.
• Distinguishing between obesity and Cushing's disease involves careful consideration of various factors.
• The overproduction of cortisol can lead to a variety of cardiovascular complications.

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