Cushing's syndrome

What causes it?

Cushing's syndrome occurs when the body is exposed to an excess of glucocorticoid hormones over a long period of time. Glucocorticoids, such as cortisol (or hydrocortisone) and corticosterone, are involved in the metabolism of fats, carbohydrates and proteins, in the control of inflammation and in helping the body to recover from stress.

The most common cause of this excess is the taking of oral steroid treatment for medical conditions such as rheumatoid arthritis and other inflammatory conditions.

Less often, the adrenal gland produces too much hormone. This may be because of a hormone-secreting tumour in the adrenal gland or because the gland is being inappropriately over-stimulated. This can occur as the result of a tumour in the pituitary gland (the gland that produces the hormone that in turn stimulates the adrenal gland).

What are the symptoms?

Cushing's syndrome causes characteristic changes in the appearance and structure of the body. These include:

• Weight gain around the chest and abdomen
• Reddish-purple stretch marks on the thighs, abdomen and arms
• Red and rounded face ('moon face')
• Excessive facial and body hair
• Thin and weak muscles of the arms and legs
• Skin that bruises easily and doesn't heal well
• Fluid retention in the legs

If left untreated, Cushing's syndrome can also be responsible for:

• Depression
• Poor libido
• High blood pressure
• Osteoporosis
• Diabetes

How is it diagnosed?

It's usually obvious someone has Cushing's syndrome, because of the characteristic ways in which the excess hormones affect the body.

Straightforward urine and blood tests can confirm the diagnosis. Other tests, such as scans and x-rays, may be needed to determine the exact cause.

What's the treatment?

When Cushing's syndrome is the result of medication, the dose is reduced.

If a tumour in the adrenal or pituitary gland is responsible, this will be removed if possible. Sometimes radiotherapy is needed to destroy a tumour in the pituitary gland if it's difficult to remove surgically.

Once treatment is completed, the symptoms gradually improve.