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.

Symptoms usually develop gradually and so the diagnosis may not be clear for some time.

Cushing’s syndrome develops if your body makes too much cortisol hormone.

Cortisol is a hormone 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 Cushings?

The most common reason for Cushing’s overall is glucocorticoid treatment -for example taking a steroid such as prednisolone for asthma, arthritis or colitis.

Spontaneous Cushing’s, originating from within the body is rare, but occurs when the adrenal glands are making too much of a hormone called cortisol (the body’s natural glucocorticoid steroid hormone).

This 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 be difficult to establish at the earlier stages and this can cause a delay in diagnosis.

Far more women than men suffer from Cushing’s, but it isn’t 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.


The commonest cause of spontaneous Cushing’s (around 70%) is a small benign tumour (growth) of the pituitary gland. This produces the 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 will solve the problem.

Alternatively, there could be a small growth in another part of your body which is having the same effect (this is called ectopic ACTH). If so, removing this growth will usually solve the problem.

Lastly, there may be a small growth in one of the adrenal glands themselves, in which 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

If the source of the problem is the pituitary gland, then the correct name is Cushing’s disease. Whereas, if it originates anywhere else, then the correct name is Cushing’s syndrome.

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.