CUSHING'S SYNDROME

What is Cushing's syndrome?

This is a clinical disease caused by the excessive level of circulating cortisol hormone.

One of the steroid hormones produced from the adrenal glands. It is essential for the survival of a person.

The pituitary gland is a small pea size gland situated in a hollow bony pouch, at the base of the brain, at the back of the bridge of the nose. It is the master gland of the endocrine system and controls the functions of the other endocrine glands. The pituitary gland releases a hormone called ACTH which enters the blood circulation and passes to the adrenal glands making these glands release cortisol.

The adrenal glands lie just above each of your two kidneys and when stimulated by ACTH release cortisol into the blood.

This can be caused by;

1. excessive intake of medicines containing cortisol for other medical reasons such as asthma, rheumatoid arthritis, connective tissue diseases
2. over production of cortisol from the adrenal glands.
3. abnormal growth in the pituitary gland called an adenoma which produces excess ACTH hormone which in turn stimulates the over production of the cortisol from the adrenal glands.
4. some cancers e.g. lung cancer can produce ACTH which can stimulate the adrenal glands to produce excessive amounts of cortisol.

If the excessive production of cortisol is caused by the abnormality in the pituitary, it is called Cushing’s Disease.

Excessive cortisol in the long term will cause brittle bones, high blood pressure, strain on circulation leading to heart attack and heart failure. It can cause weak muscles, brittle bones, thinning of the skin and increase likelihood of infections. Life expectancy in Cushing's is dramatically shorter than that of a normal person.

It can develop slowly and might be unnoticed for sometime.
You may notice

1. Weight gain, usually around the trunk especially the tummy but the arms and legs remain thin quite unlike simple obesity.
2. Round face- also called moon face
3. Thin skin which can easily bruises, increased pigmentation, abnormal violet coloured stretch marks called striae
4. Excessive and abnormal facial and body hair growth. Excessive acne. Loss of scalp hair
5. Weak muscles, especially difficulty standing, arising from the chair and going upstairs
6. Difficulty with healing of any wound
7. Excessive swings of mood possibly depression
8. Weak bones which easily fracture with the slightest bump.
9. High blood pressure
10. Diabetes mellitus

A specialist will arrange special tests to confirm the diagnosis and to identify the site of excessive cortisol production.

1. 1 mg overnight dexamethasone suppression test

Dexamethasone is a steroid. When you take dexamethasone, this replaces the body’s own cortisol. Therefore the morning after the dexamethasone the normal person has very low cortisol level. If the patient has Cushing’s then the cortisol level remains high.

2. 24 hour urine collection to measure for cortisol

This is to check the amount of total cortisol output in the urine. In Cushing’s this level will be high.

If the initial tests indicate excessive amount of cortisol production, you will need to come into hospital for additional special tests for confirmation and to find the actual site of excessive production.

1. Measurement of the cortisol level at different times of the day especially at midnight to check the rhythm of cortisol production.

2. Further measurement of 24-hour urine output for cortisol

3. Measurement of blood cortisol and ACTH before and after taking the different strength of dexamethasone at very precise regular time intervals. These tests take some days to perform but only require you to take tablets of dexamethasone at 6 hourly intervals with a blood test daily

4. You may also have to have a CRF test whereby measurement of ACTH and cortisol are measured in your blood after the stimulation with a hormone called CRF which is given by injection..

5. Additional tests will be required possibly of your adrenals, pituitary and other sites as required using MRI or CT scanning .

6. Measuremento of different pituitary hormone if the Cushings is due to an adenoma of the pituitary.

7. A special scan to check the strength of the bones is also performed as excess cortisol can cause brittle bones.

All the above tests are very important to decide the site and degree of excess cortisol production before the specialist can advise you of the treatment required.

This depends on the cause.

1. If it is due to excessive intake of steroid containing medicine, the aim will be to rebalance the medicine so as to find the most effective dose which does not cause you to develop Cushing’s. This will require close monitoring by the specialist or the addition of another medicine to help reduce the dose of steroid required.

2. If it is due to excessive production from the tumour of an adrenal, the treatment will be to remove the tumour (adrenalectomy). After the operation you will need to take two different steroid replacements medicines namely hydrocortisone and fludrocortisone.

3. If it is due to excessive production from the pituitary, you will require surgery to remove the abnormal growth of the pituitary (hypophysectomy). After the operation you will most likely require radiotherapy to prevent recurrence. In some patients where hypophysectomy and radiotherapy fail to cure the Cushing’s then both adrenals may also have to be removed. Depending on the amount of pituitary removed, you may require replacement of the different hormones produced by the pituitary.

4. If the cause is an ectopic tumour such as a lung tumour then often this will be removed surgically. If this fails to cure the Cushing’s then both adrenals will have to be removed. Sometimes the ectopic tumour is so small that it cannot be found and so cannot be removed.. This often happens with the rare carcinoid type of tumour and then the Cushing’s can only be controlled by removal of both adrenals.

Approximately six weeks after the treatment is complete , you will need to come in again for the tests to make sure that the Cushing’s has been successfully treated.

You may require repeated scan of adrenal/pituitary or the bone scan in due course.

ADDITIONAL POINTS

1. If you require life long replacement therapy after the surgery, you will get free prescription.

2. If you require cortisol replacement, you will require to increase the dose at the time of acute illness, you should carry a steroid card and wear a medi-bracelet and should always inform doctors of your replacement therapy.
   
3. You should inform the DVLC and Insurance Company of your condition.
   
4. Muscle weakness should recover after the treatment of Cushing’s although it may take time.
   
5. You may have very little or no steroid at all after the surgery and may require hydrocortisone, which is a steroid. This dose will be adjusted to maintain the normal requirements of the body.
   
6. It is very important to have check up by a specialist so that your condition can be monitored life long.

The Pituitary Foundation
PO Box 1944
Bristol, BS99 2UB.
Tel/Fax 0117 927 3355
e-mail- helpline@pitpat.demon.co.uk

Cushing Care
Meadows, Woodplumpton Village, Preston, Lancashire. PR4 0LJ.
Tel; 01772 690680.

This provides information and support to Cushing’s sufferers and their families. A patient runs this.

Why not try the website: http://world.std.com/~csrf/

or www.pituitary.org.uk

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Ó NHS Tayside; 2006; version 1.0

Disclaimer; no liability whatsoever is accepted for information given and all such information, especially with regard to drug usage (UK version provided), must be checked with a person’s health provider.