What are the 4 underlying causes of Cushings syndrome?

Inhaltsverzeichnis Show

Symptoms of Cushing’s syndrome
The hormone cortisol
Causes of Cushing’s syndrome
Tumour of the pituitary gland
Tumour of the adrenal gland
ACTH-producing tumours
Multiple endocrine neoplasia 1 (MEN1)
Glucocorticoid hormone therapy
Diagnosis of Cushing’s syndrome
Treatment for Cushing’s syndrome
Where to get help
Things to remember

Cushing's syndrome is a condition caused by having too much of a hormone called cortisol in your body. It can be serious if it's not treated.

Cushing's syndrome is uncommon. It mostly affects people who have been taking steroid medicine, especially steroid tablets, for a long time. Steroids contain a synthetic version of cortisol.

Very rarely, it can be caused by the body producing too much cortisol.

This is usually the result of:

a growth (tumour) in the pituitary gland in the brain
a tumour in 1 of the adrenal glands above the kidneys

The tumours are usually non-cancerous (benign). They're most common in young women.

Symptoms of Cushing's syndrome can start suddenly or gradually. They tend to get slowly worse if not treated.

One of the main signs is weight gain and more body fat, such as:

increased fat on your chest and tummy, but slim arms and legs
a build-up of fat on the back of your neck and shoulders, known as a "buffalo hump"
a red, puffy, rounded face

Other symptoms include:

skin that bruises easily
large purple stretch marks
weakness in your upper arms and thighs
a reduced sex drive (low libido) and fertility problems
depression and mood swings

Cushing's syndrome can also cause high blood pressure, which can be serious if not treated.

See a GP if you have symptoms of Cushing's syndrome, especially if you're taking steroids.

Do not stop taking your medicine without getting medical advice.

Lots of things can cause similar symptoms to Cushing's syndrome, so it's a good idea to get checked to find out what the problem is.

Your doctor may suspect Cushing's syndrome if you have typical symptoms and are taking steroid medicine.

If you're not taking steroids, it can be difficult to diagnose because the symptoms can be similar to other conditions.

If Cushing's syndrome is suspected, the amount of cortisol in your body can be measured in your:

If these tests show a high level of cortisol, you may be referred to a specialist in hormone conditions (endocrinologist) to confirm or rule out Cushing's syndrome.

You may also need other tests or scans to find out the cause.

Cushing's syndrome usually gets better with treatment, although it might take a long time to recover completely.

Treatment depends on what's causing it.

If it's caused by taking steroids:

your steroid dose will be gradually reduced or stopped

If it's caused by a tumour, treatment may include:

surgery to remove the tumour
radiotherapy to destroy the tumour
medicines to reduce the effect of cortisol on your body

Speak to your doctor about the benefits and risks of the different treatment options.

Read more about Cushing's syndrome and the main treatments from the Pituitary Foundation

Page last reviewed: 25 March 2021
Next review due: 25 March 2024

Cushing’s syndrome is a collection of hormonal disorders resulting from high levels of the hormone cortisol.
Many overweight people with hypertension or diabetes have some features of Cushing’s syndrome. Tests can be done to rule out this possibility.
Causes include certain tumours and glucocorticoid drug therapy for inflammatory disorders.
Without treatment, Cushing’s syndrome can be fatal.

Cushing’s syndrome is a collection of hormonal disorders characterised by high levels of the hormone cortisol. Another name for Cushing’s syndrome is hypercortisolism. Some people have Cushing’s syndrome symptoms when they take glucocorticoid hormones to treat inflammatory conditions such as asthma, lupus or rheumatoid arthritis. Other causes include tumours of the pituitary and adrenal glands, and tumours in other areas of the body. Around one in 50,000 people are affected by Cushing’s syndrome, with females more susceptible to some forms than males. Without treatment, the disorder can be fatal.

Many overweight people with hypertension or diabetes have some features of Cushing’s syndrome. Tests can be done to rule out this possibility.

Symptoms of Cushing’s syndrome

Some of the symptoms include:

Weight gain around the abdomen, and obesity
Wasting of the limbs
A ‘buffalo’ hump of fat high on the back
Round, red and puffy-looking face (‘moon face’)
Thin skin, easily bruised, slow healing and ulcers
Muscular weakness
Thirst
Frequent urination
Headaches
High blood pressure
High white blood cell count, low serum potassium
High blood sugar (in 80 per cent of patients)
Mood swings, irritability, anxiety, depression
Impotence
Irregular menstrual periods or no menstrual periods
Increased facial hair in women
Weakened bones, susceptibility to bone fractures (especially in ribs and spine), osteoporosis and backache
Susceptibility to pneumonia and TB.

The hormone cortisol

Cortisol is made by the adrenal glands. When cortisol levels are too low, the pituitary secretes the stimulating hormone adrenocorticotropin (ACTH). High levels of cortisol prompt the pituitary to decrease ACTH, which slows cortisol production.

Cortisol is essential to life. Its functions include:

Helping the body manage stress
Helping to maintain constant blood sugar levels
Inhibiting inflammation
Contributing to the maintenance of constant blood pressure
Contributing to the workings of the immune system.

Causes of Cushing’s syndrome

The symptoms of Cushing’s syndrome are caused by damage to body tissues due to high levels of the hormone cortisol in the blood over a long time. The disorders that trigger high cortisol levels include:

Tumour of the pituitary gland
Tumour of the adrenal gland
ACTH-producing tumours (ectopic) elsewhere in the body
Multiple endocrine neoplasia 1 (MEN1)
Glucocorticoid hormone therapy.

Tumour of the pituitary gland

This form is known as Cushing’s disease and accounts for about seven in 10 cases of Cushing’s syndrome. One type of pituitary gland tumour secretes additional ACTH, which forces the adrenal glands to make too much cortisol.

These tumours are usually benign non-cancerous adenomas and they occur more often in women than men (3 to 1). Complications include diabetes, kidney stones and mental disturbances, such as psychosis.

Tumour of the adrenal gland

A tumour on one of the adrenal glands triggers the production of high cortisol levels. The tumours are usually non-cancerous. The pituitary responds by dropping its level of ACTH hormone, which causes the healthy adrenal gland to shrink. Onset of symptoms can be quite rapid.

ACTH-producing tumours

In rare cases, other tumours in the body can produce ACTH. Approximately 17 per cent of Cushing’s syndrome develops this way. Fifty per cent of cases result from lung tumours. Other causes come from tumours in the thymus, pancreas and thyroid gland. This type of Cushing’s syndrome is sometimes referred to as ‘ectopic’.

Multiple endocrine neoplasia 1 (MEN1)

The pituitary, pancreas, adrenals, thyroid and parathyroid glands belong to the endocrine system. MEN1 is an inherited condition characterised by tumours on at least two of these glands. If the pituitary or adrenals are affected, Cushing’s syndrome can result.

Primary pigmented micronodular adrenal disease occurs in children and young adults, where there is an increase in the number of cortisol-producing adrenal tumours.

Glucocorticoid hormone therapy

Glucocorticoid drugs are commonly used to ease the symptoms of inflammatory conditions such as asthma, rheumatoid arthritis and lupus erythematosus. These drugs can trigger symptoms of Cushing’s syndrome, although the effects should reverse once the drug therapy is stopped. However, suppression of a person’s own adrenal function may persist, creating adrenal insufficiency, which may require replacement therapy during gradual withdrawal of glucocorticoid drugs.

Diagnosis of Cushing’s syndrome

Diagnosis of Cushing’s syndrome involves discovering high cortisol levels and uncovering the cause. Diagnosis may involve:

Physical and visual examination, with full family medical history
Blood tests to check if Cushing’s is of pituitary or ectopic origin, and to compare ACTH levels elsewhere in the body. A combination of these two tests gives great accuracy for diagnosis
Urine tests
Dexamethasone suppression test using steroids to check the body’s reaction to glucocorticoid drugs
Magnetic resonance imaging (MRI) scans and computed tomography (CT) scans to check for gland size and evidence of tumours.

Treatment for Cushing’s syndrome

Treatment depends on the cause and may include:

Tumour of the pituitary gland – the tumour is surgically removed. Other options include radiation therapy and drug therapy to shrink the tumour and stop it from producing hormones. Various hormone replacements may be required after pituitary surgery.
Tumour of the adrenal gland – the tumour is surgically removed. Replacement hormone therapy may be necessary for a short while.
ACTH-producing tumours – treatment includes surgery to remove the tumour, followed possibly by chemotherapy, immunotherapy and radiation therapy. Medication can reduce the ability of the adrenal glands to make cortisol.
MEN1 – radiation therapy and surgery are used to remove the tumours and associated glands. Ongoing hormone replacement therapy is needed after surgery.
Glucocorticoid hormone therapy – induced Iatrogenic Cushing’s syndrome – symptoms will gradually resolve if treatment can be reduced or stopped, which depends on the activity of the disorder. Treatment should never be stopped suddenly because of the possibility of adrenal suppression.

Where to get help

Your doctor
Endocrinologist
The Australian Addison's Disease Association Inc. Tel. (02) 6652 4761; (02) 6657 2571.
Australian Pituitary Foundation Tel. 1300 331 807
The Western Australian Cushing's Disease Association Tel. (08) 9402 4394; (08) 9390 2132.

Things to remember

Cushing’s syndrome is a collection of hormonal disorders resulting from high levels of the hormone cortisol.
Many overweight people with hypertension or diabetes have some features of Cushing’s syndrome. Tests can be done to rule out this possibility.
Causes include certain tumours and glucocorticoid drug therapy for inflammatory disorders.
Without treatment, Cushing’s syndrome can be fatal.

This page has been produced in consultation with and approved by:

Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional. The information and materials contained on this website are not intended to constitute a comprehensive guide concerning all aspects of the therapy, product or treatment described on the website. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions and to ascertain whether the particular therapy, service, product or treatment described on the website is suitable in their circumstances. The State of Victoria and the Department of Health shall not bear any liability for reliance by any user on the materials contained on this website.