What is Cushing’s?
The condition is named after Harvey Cushing, an eminent American neurosurgeon who described the first patients with this condition in 1912.
Cushing’s syndrome develops if your body makes too much of a hormone called cortisol.
Cortisol is made by the adrenal glands (two small glands which lie just above each kidney) and it is vital for life. It has several functions including:
- Helping to regulate blood pressure
- Helping to regulate the immune system
- Helping to balance the effect of insulin to keep blood sugar normal
- Helping the body to respond to stress
Why do we get Cushing’s?
The most common reason that people develop Cushing’s is glucocorticoid treatment – for example, taking a steroid such as prednisolone for asthma, arthritis or colitis. This type of Cushing’s is known as exogenous Cushing’s.
Another type of Cushing’s, known as spontaneous Cushing’s, occurs when the condition originates from within the body (e.g. is not due to taking medication). This is rare but occurs when the adrenal glands are making too much cortisol (the body’s natural glucocorticoid steroid hormone).
Spontaneous Cushing’s may happen for one of several reasons, so you will have tests to find out which reason applies to you. The quoted incidence of Cushing’s is 1 in 200,000 but it is now being found more frequently when it is specifically investigated. The symptoms of Cushing’s can be very wide ranging and thus the diagnosis may not necessarily be considered. It can also be difficult to establish at the earlier stages and this can cause a delay in diagnosis.
Far more women than men experience Cushing’s but it is not known why. It is most commonly diagnosed between the ages of 30 to 40. Although it is rare in children, some as young as six have been diagnosed. There are no environmental triggers known and it’s not hereditary.
Causes
A pituitary gland tumour
The most common cause of spontaneous Cushing’s (accounts for around 70% of cases) is a small benign (non-cancerous) tumour of the pituitary gland. This tumour causes the pituitary gland to produce too much of a hormone called ACTH, (adrenocorticotrophic hormone), which goes through the blood stream to the adrenal glands and causes them to release too much cortisol. In this case there is a good chance that an operation on your pituitary gland, to remove the tumour, will solve the problem.
A tumour elsewhere in the body
Sometimes, the tumour that is causing Cushing’s is not found in the pituitary gland. There could be a small growth in another part of your body that is producing ACTH (this is called ectopic ACTH), leading to overproduction of cortisol. If so, removing this growth will usually solve the problem.
Tumour of the adrenal glands
The adrenal glands are small, hormone-secreting glands that sit above each kidney. A small growth in one of the adrenal glands can cause Cushing’s. In this case, an operation will be needed to remove that gland. In some circumstances it may be necessary to remove both adrenal glands to solve the problem.
Cushing’s syndrome vs Cushing’s disease
Cushing’s syndrome is the name given to any cause of high cortisol. This could be because of many different reasons, such as those listed above. If Cushing’s is caused by a growth in the pituitary gland then the correct name is Cushing’s disease.
Cyclical Syndrome
Sometimes, the amount of cortisol causing the condition can vary greatly. This is called ‘Cyclical Cushing’s’ with varying symptoms, often over months or even years depending on the levels of cortisol. This can cause difficulty and delays in diagnosis. Occasionally, repeated testing by your endocrinologist will be needed to assess whether you have this more uncommon type of Cushing’s.
Cortisol and Cushing’s
The video below explores what cortisol is and how overproduction of this hormone leads to the symptoms seen in Cushing’s.
By loading the video, you agree to YouTube’s privacy policy.
Learn more
