Cushing's syndrome

Also known as Cushing syndrome

Key points about Cushing's syndrome

  • Cushing’s syndrome is caused by too much of the hormone cortisol in your body.
  • It can be caused by long-term use of corticosteroid medicines or your adrenal glands producing too much cortisol.
  • Cushing's syndrome may also be caused by a pituitary or adrenal gland tumour.
  • The most common symptoms are weight gain (often with a 'moon face' and 'buffalo hump') while arms and legs become thinner and weaker. 
  • If you're taking long-term corticosteroid medicines (eg, prednisone, hydrocortisone) DO NOT stop taking them without your healthcare provider's advice. 
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(Demystifying Medicine McMaster, US, 2023)

Cushing’s syndrome is caused by too much cortisol in your body. Cortisol is a hormone made by your adrenal glands, which sit on top of your kidneys. These glands are stimulated to produce cortisol by another hormone (called ACTH) which is released by the pituitary gland (found near your brain).

Infographic showing how cortisol is made by your adrenal glands
Image credit: Healthify He Puna Waiora

helps your body to respond to stress. It regulates your blood pressure, and immune system and balances the effect of insulin to keep your blood glucose in a normal range.

Your body can be exposed to too much cortisol in 2 ways:

  • Long-term use of corticosteroid medicines (most common).
  • Your adrenal glands (repe kōihi) producing too much cortisol.

Long-term use of corticosteroid medications

Corticosteroid medications (eg, prednisone, hydrocortisone) contain a man-made version of cortisol and are used to treat many conditions associated with inflammation, eg, rheumatoid arthritis (mate rumatika), lupus and asthma (huangō). They can also be used to prevent your body from rejecting a transplanted organ.

Corticosteroids can be taken orally (by mouth), inhaled (eg, for asthma) or topically (put on your skin). Short-term use of oral corticosteroids and the use of inhaled and topical corticosteroids carry a very low risk of developing Cushing’s syndrome. Long-term use of oral corticosteroids (more than 3 weeks) carries a higher risk.

Adrenal glands producing too much cortisol

A tumour in an adrenal gland can mean too much cortisol is produced. Sometimes, a tumour in your pituitary gland (or elsewhere in your body) may make too much ACTH (the hormone that stimulates the adrenal glands to make cortisol). A tumour in your pituitary gland is called Cushing’s disease.

Cushing’s syndrome caused by a tumour is 5 times more common in women than men and it usually occurs between the ages of 25 and 40 years. However, it's quite rare.

There are many symptoms of Cushing’s syndrome and you may only have a few. Symptoms vary from person to person and can range from mild to severe.

The most common symptoms are:

  • weight gain, especially around your stomach, with thin arms and legs
  • a round, moon-shaped face
  • a build-up of fat on the upper back between the shoulders (known as 'buffalo hump')
  • pink or purple stretch marks around your arms, stomach, breasts and thighs
  • increased blood pressure.

Cushing’s syndrome can also cause changes to your skin, bones, muscles and mood.

  • Skin changes: Thin skin that bruises easily, slow-healing cuts, acne or an increase in face and body hair in women.
  • Bone and muscle changes: Osteoporosis (thin and weak bones) and muscle weakness, especially in your upper legs and arms.
  • Mood changes: Depression, anxiety, feeling irritable, problems with memory and concentration and feeling tired all the time.

Other symptoms include diabetes (new or worsening). irregular periods for women, problems getting an erection for men and an increase in infections.

Often the diagnosis of Cushing’s syndrome can take some time, as many of the symptoms can be caused by other disorders. If your healthcare provider suspects Cushing’s syndrome, you may need to have some tests. Your urine, saliva or blood is tested. You may have just 1 of these tests or a combination.

Urine test

You may be asked to collect your urine (wee/mimi) over 24 hours. The amount of cortisol in your urine is measured.

Saliva test

You may be asked to collect a sample of your saliva (hūare) late at night, usually for 3 nights in a row.

Blood test

You may be sent for a dexamethasone suppression test. For this you'll need to have a blood test 2 days in a row. 

  • Day 1: You have a blood test at 9am (this will show how much cortisol is in your blood) , then take a dose of dexamethasone tablets at 11pm the same night.
  • Day 2: You have a repeat blood test at 9am.The amount of cortisol in your blood changes during the day so a single blood test isn't enough for a diagnosis.

Dexamethasone is a medicine that stops your body producing cortisol. If you have Cushing’s syndrome, taking dexamethasone won't change how much cortisol your body makes.

If these tests show that you have too much cortisol in your body, you may be asked to go for another blood test to measure ACTH. This can help to find the cause of your high cortisol levels. 

Treatment depends on what's causing your high level of cortisol. The goal of treatment is to reduce the amount of cortisol.

Corticosteroid medicine use 

If corticosteroid medicine is causing Cushing’s syndrome your healthcare provider may try lowering your dose gradually to minimise symptoms while still treating the disease it's being used for. They may also try you on a different non-corticosteroid medicine. 

It's important not to reduce the dose of your corticosteroid medication or stop taking it on your own. Do so only under your healthcare provider's supervision. Stopping these medicines suddenly could lead to low cortisol levels which may be harmful – even life-threatening. Slowly tapering off (lowering) corticosteroid medicines allows your body to restart normal cortisol production.

Pituitary or adrenal gland tumour

If a pituitary or adrenal gland tumour is causing Cushing’s syndrome your treatment options may be surgery to remove the tumour or radiation treatment or chemotherapy.

  • Be familiar with the symptoms of Cushing’s syndrome if you're on long-term corticosteroid medication.
  • Discuss any symptoms you may have with your healthcare provider.
  • Take your corticosteroid medicine as prescribed.
  • Don’t stop taking your corticosteroid medication without your healthcare provider's help, as your body may have stopped producing enough cortisol, which can cause serious harm.
  • Once the underlying cause of your Cushing’s syndrome has been treated, you should start to feel better and have more energy. It’s important to continue to exercise daily but avoid high impact exercises due to your increased risk of osteoporosis. Your healthcare provider can recommend appropriate exercises.
  • Make sure you eat a healthy diet high in calcium and Vitamin D to help maintain and strengthen your bones.
  • Cushing’s syndrome can cause changes to your mood. Look after your mental health and seek help from a healthcare professional if your mood hasn’t improved once your symptoms are being managed.
  • Cushing’s syndrome can be very serious if left untreated. As it can be hard to diagnose, don’t give up seeking advice and tests from your healthcare provider if you notice any symptoms.

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Claire Salter, Pharmacist, Tauranga

Last reviewed: