Cushing's Syndrome

What is Cushing's syndrome?

Cushing's syndrome occurs when glucocorticoid levels in the body are too high over a long period of time. This can be caused by taking too much glucocorticoid medication (exogenous), or high levels of glucocorticoid made by your own body (endogenous):
Exogenous: long term steroid treatment is the commonest cause of cushing's syndrome. Steroid medicine, such as prednisolone, may have been prescribed to you for arthritis, cancer or muscle problems.
Endogenous: this means that your body makes too much of a steroid called cortisol. Although rare, this type of cushing's syndrome can be very serious.


Five in one million people develop cushing's syndrome due to endogenous cortisol every year. Most patients are aged 20 to 50 years of age. Women are more commonly affected than men

What is cortisol?

Cortisol is a steroid hormone made by your adrenal glands which lie above your kidneys. Cortisol helps your immune system, blood pressure and enables your body to cope with stress. It also assists in regulating blood sugar levels.

What causes high levels of cortisol?

Pituitary adenoma (Cushing's Disease): 80% of cases are caused by this benign (non-cancerous) tumour of the pituitary gland. This gland releases ACTH and this stimulates your adrenal to produce cortisol.

Adrenal Hyperplasia: the cells in the adrenal multiply uncontrollably and hence release too much cortisol. Adrenal hyperplasia can be caused by a benign or malignant (very rare) tumour.

Rare cancers such as lung cancer can release ACTH stimulating cortisol.

Long term steroid medication.

Other causes such as depression or excess alcohol.


High levels of cortisol can go unnoticed for a long time, but symptoms can develop:
  • Excess weight - especially around in your waist
  • Your arm and legs can become thinner out of proportion to your trunk
  • Muscle weakness in your arms and legs (especially in the muscles close to your trunk)
  • Thin skin which easily bruises
  • Stretch marks (striae)
  • Facial weight gain
  • Facial redness and hair
  • High blood pressure
  • Diabetes
  • Tiredness
  • Depression and mood swings
  • Low libido (sex drive)
  • No or irregular periods in women
  • Thin bones (osteoporosis)
  • Water retention (edema) around your ankles
  • More susceptible to infections
  • Poor height growth in children


You GP may refer you to an endocrinology specialist as you will need tests to confirm that you cortisol levels are very high.
Cortisol levels change throughout the day, so the tests are designed to measure cortisol levels over the day. These include:

Collecting all the urine that you pass throughout the day into a plastic container. The whole amount is then analysed to measure cortisol levels. A blood test after medication to try to suppress your cortisol levels - the medication does not work and levels are still high in cushing's syndrome. A blood or saliva test at night when cortisol levels are usually low

After this, you may need to have investigations to ascertain the cause of your high cortisol levels such as scans or more specialised blood tests.


Treatment of cushing's syndrome depends on the exact cause. For example, if excess cortisol is being released from enlarged or abnormal adrenal glands, they will need to be removed, and you will probably need to take life-long steroid replacement therapy.

Further help and support

Protocol of Diagnosis and Care on the Cushing syndrome.
ACTH is the Association for Cushing's Treatment and Help and provides support for patients:

Tel: 01628 670389

The Pituitary Foundation helps you and your carers:

Tel (Helpline): 0845 450 0375

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