Cushings Disease

What Is It?

Cushings disease is caused by a pituitary adenoma (a benign pituitary tumor) which secretes adrenocorticotropic hormone (ACTH). Cushing's disease is named for Harvey Cushing, considered to be the father of modern neurosurgery.

ACTH is a hormone that normally stimulates the cortex of the adrenal glands to secrete its hormones, predominately cortisol. Cortisol has effects on many different aspects of metabolism but is particularly important for the stress response. It is secreted in times of stress and increases blood pressure and blood sugar, amongst other metabolic effects.

With an ACTH secreting adenoma, the adrenal gland is over-stimulated and very high levels of cortisol occur.

Do not confuse Cushings disease with Cushing's syndrome, which is the general name for the set of symptoms seen with excess levels of cortisol from any cause (not necessarily a pituitary adenoma secreting ACTH).

What Types of Symptoms Are Typical?

High levels of cortisol have many effects. High blood pressure and high blood sugar (diabetes mellitus) are common. In addition, over time the metabolic changes lead to characteristic changes in the body. For example, weight gain is common. The weight gain is mostly central (central obesity) with sparing of the arms and legs. There is also fat deposition in the face, leading to what is called "moon facies", and in the back of the neck, called a "buffalo hump". Skin growth and wound healing is also impaired and can lead to stretch marks, or "striae". Some patients experience various psychological disturbances. Many other effects are also possible and in the long-term, untreated patients may develop significant heart disease, opportunistic infections, diabetes and other problems.

In addition to this syndrome, termed Cushing's syndrome, patients with larger ACTH-secreting tumors can have any of the symptoms associated with other pituitary tumors, including headache, visual changes and hypopituitarism of other hormones.

How Is The Diagnosis Typically Made?

Like other brain tumors, a CT scan or MRI scan is often used to detect the tumor. In the case of Cushing's disease, occasionally the tumor is very small and cannot be seen adequately.

As with other pituitary adenomas, blood tests are used to evaluate the pituitary hormones. In the case of Cushings disease, particularly in those patients with very small tumors which cannot be adequately seen on MRI, a special procedure called inferior petrosal sinus sampling is occasionally used. In some cases, this procedure helps to confirm that the excess ACTH is coming from the pituitary and may help to localize the tumor to one side or the other. It is performed by placing a small catheter into a vein-like structure, called the inferior petrosal sinus, which drains some of the blood coming from the region of the pituitary gland.

What Are Some Common Treatments?

The most common treatment for Cushings disease is surgical removal of the tumor through a transsphenoidal operation. When the tumor is small and cannot be easily seen this can be difficult to obtain a complete cure. In rare cases part or all of the pituitary gland is removed. In extreme cases where cortisol levels remain high despite multiple attempts to remove the tumor, both adrenal glands are removed to prevent the long-term complications and morbidity of untreated Cushing's syndrome. In the case of pituitary gland removal and/or adrenal gland removal, life-long hormonal replacement therapy is required.

As with other pathologies, each tumor and patient is different, so it is hard and inappropriate to make generalizations about what treatment plan is most appropriate. Each patient should discuss their options with their own physician team.

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Important Note: This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.

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