Cushing's syndrome - Treating Cushing's syndrome

Treatment for Cushing's syndrome will depend on what is causing the high levels of cortisol to accumulate in your body.

If your Cushing's syndrome is caused by the long-term use of corticosteroids (iatrogenic Cushing’s syndrome), you will need to gradually reduce your dosage to the lowest possible dose required to control the condition being treated (see below).

If your Cushing's syndrome is caused by a tumour (endogenous Cushing’s syndrome), the following treatment options are available:

• cortisol-inhibiting medications
• radiotherapy
• surgery 

Reducing corticosteroid use

It is usually not safe to suddenly stop taking corticosteroids.

If you have been taking corticosteroids for a long time, your body may stop producing natural steroids. If you suddenly stop taking your medication, you may experience symptoms such as fatigue, vomiting and diarrhoea.

Also, you may need to continue taking your medication until the symptoms of the condition being treated are under control.

If you have only been taking corticosteroids for a few days, it may be possible to safely stop the dose straight away.

There is no ‘one size fits all’ plan for withdrawing treatment with corticosteroids. However, for most people, a gradual reduction is recommended. After a while a blood test should tell if your body is producing natural steroids.

It is only safe to stop taking steroids completely once your body is producing them naturally. This can take from a few months to more than a year. During this time you may need treatment for some of the symptoms of Cushing's syndrome, such as medication to lower your blood pressure.

Cortisol-inhibiting medications

Cortisol-inhibiting medications are designed to block the adverse effects of cortisol. They tend to be used short-term as a preparation for surgery or for a short time after surgery or radiotherapy to help make these treatments more effective.

Occasionally, cortisol-inhibiting medications are used on a long-term basis in people unwilling or unable to have surgery. Ketoconazole and metyrapone are two widely used cortisol-inhibiting medications.

Ketoconazole is not licensed for the treatment of Cushing’s syndrome. This means the manufactures designed and tested the medication for treating another condition (fungal infection), and it was subsequently found to also be useful for treating Cushing’s syndrome.

However, there have been no large scale safety trials of ketoconazole in people with Cushing’s syndrome. The doctor in charge of your care will be able to provide more information about ketoconazole.

Find out more about the medicines that are licensed to treat Cushing's syndrome.

Surgery

Surgery may be needed to remove a tumour in the pituitary gland or adrenal gland. Removing a tumour from the lungs is much more challenging and may not be possible.

Pituitary gland removal

Surgery to remove a tumour in the pituitary gland is known as transsphenoidal adenoectomy. Under general anaesthetic, the surgeon removes the pituitary tumour either through your nostril or an opening made in your upper lip.

This type of surgery has a good track record of success. More than 80% of cases are cured. If necessary, the procedure can be repeated, usually with very good results.

Adrenal gland removal

In most cases, only one adrenal gland will need to be removed. To do this, laparoscopic (keyhole) surgery is usually used.

During the procedure, the surgeon makes a small incision in your abdomen and passes tiny instruments through it to remove your adrenal gland. The advantage of this approach is that you will feel less pain after surgery and have minimal scarring.

Laparoscopic surgery has a good record of success, with over 65% of people’s symptoms being completely cured.

In some cases, removing both of your adrenal glands may be recommended, so that they are unable to produce cortisol. This may be needed if your Cushing’s syndrome symptoms put your long-term health at risk – for example, if you have poorly controlled high blood pressure (hypertension).

Lung tumour

If the tumour is located deep inside your lung, it may not be possible to destroy or remove it safely without seriously damaging the lung.

If this is the case, an alternative approach may be recommended, such as using cortisol-inhibiting medication or completely removing the adrenal glands to stop the production of cortisol.

Radiotherapy

Radiotherapy may be recommended if pituitary gland surgery is unsuccessful or if you are unable to have surgery. It involves using high-energy X-rays to shrink the tumour.

A type of radiotherapy known as stereotactic radiosurgery (SRS) is increasingly being used to treat pituitary tumours. It uses a series of movable frames to hold your head in a precise position. A computer is then used to send energy rays to the exact location of the pituitary tumour.

SRS minimises the chances of other parts of your brain being accidentally damaged. It usually takes just one session. As the procedure is only available at a number of specialised centres, it's likely you will have to travel to receive treatment. There may also be a waiting list for treatment.

The results of SRS are good, with around 75% of people's symptoms being completely cured.

Complications of surgery

Complications can sometimes develop following surgey for Cushing's syndrome. Loss of hormonal function and Nelson's syndrome are two possible complications. These are described below.

Loss of hormonal function

The surgeon will try to save as much of your pituitary or adrenal gland as possible to preserve their normal functions of producing hormones. However, in some cases, this may not possible, particularly if you have a large tumour.

If you have both of your adrenal glands removed, you'll lose normal hormonal function. Radiotherapy also increases your risk of losing normal hormonal function.

If you lose normal hormonal function, you'll need to take synthetic (man-made) hormones. This is sometimes known as hydrocortisone replacement therapy (not to be confused with hormone replacement therapy, which is often used to treat the menopause).

Hydrocortisone comes in tablet form. Most people need to take two to three tablets a day. If your glands recover their normal function after a few months, treatment can be stopped. However, it may be that you need to take hydrocortisone for the rest of your life.

Most people tolerate hydrocortisone well, but it can take a while to work out the best dose for you. During this time, you may experience some Cushing's syndrome-like side effects, such as weight gain and thinning of your skin.

Nelson’s syndrome

Nelson’s syndrome is a fairly common complication that occurs in people who have had both of their adrenal glands removed because they were unresponsive to surgery or radiotherapy.

Nelson’s syndrome is a rapidly growing tumour inside your pituitary gland. The symptoms include:

• darkening of your skin
• headaches 
• vision problems, such as partial vision loss or double vision

The cause of Nelson’s syndrome is poorly understood. One study carried out several years ago found that one in four people who had both adrenal glands removed went on to develop Nelson’s syndrome. However, this figure is likely to be lower today due to improvements in the treatment of Cushing’s syndrome.

The recommended treatment for Nelson’s syndrome is to surgically remove the tumour. This may be followed by an additional course of radiotherapy.