Changes in body chemistry and physical appearance caused by excessive amounts of corticosteroid hormones
- More common in females
- Age, genetics, and lifestyle are not significant factors
Corticosteroid hormones are involved in the regulation of metabolism (the chemical reactions that continually occur in the body) and play a part in the control of salt and water balance and blood pressure. In Cushing’s syndrome, an excess of corticosteroids causes disruption of these control mechanisms. The distribution of fat around the body and the growth of body hair are affected, resulting in significant changes in physical appearance. Depression and other psychological problems may also develop. Cushing’s syndrome is more common in women than in men.
What are the causes?
The most common cause of Cushing’s syndrome is long-term treatment with oral corticosteroid drugs. These drugs mimic the effects of natural corticosteroids produced by the adrenal glands. Less commonly, Cushing’s syndrome is due to the overproduction of corticosteroids by the adrenal glands. This may be caused by a hormone-secreting tumour in one of the adrenal glands (see Adrenal tumours) or by a tumour in the pituitary gland (see Pituitary tumours) that produces the hormone ACTH, which stimulates the adrenal glands.
Some cancers, such as primary lung cancer, produce hormones that mimic pituitary hormones and may cause Cushing’s syndrome as a result.
What are the symptoms?
The symptoms of Cushing’s syndrome appear gradually and become increasingly obvious over a period of weeks or months. Any of the following may occur:
Changes in the appearance of the face, which may become red and rounded.
Weight gain concentrated around the chest and abdomen.
Excessive growth of facial or body hair (more noticeable in women).
In women, irregular menstruation. Eventually, menstruation may stop.
Reddish-purple stretch marks on the abdomen, thighs, and arms.
Pads of fat between the shoulder blades at the base of the neck.
Difficulty climbing stairs, associated with muscle wasting and weakness of the legs. Arms may also be affected.
Tendency to bruise easily, especially on the limbs.
Lack or loss of sexual drive; men may develop erectile dysfunction.
Depression and mood swings.
If the condition is left untreated, it may eventually lead to complications such as high blood pressure (see Hypertension), thinning of the bones (see Osteoporosis), diabetes mellitus, and chronic heart failure.
How is it diagnosed?
If you have been taking large doses of corticosteroid drugs, your doctor will probably be able to diagnose Cushing’s syndrome from your symptoms. Otherwise, tests on blood or urine may be carried out to look for raised levels of natural corticosteroids. Abnormally high levels of corticosteroids may indicate that you have an adrenal tumour or that your adrenal glands are overstimulated.
Once the diagnosis is confirmed, the cause will be investigated. You may have tests in hospital to distinguish between raised hormone levels that may be due to a pituitary tumour and those possibly due to an adrenal tumour. MRI or CT scanning of the adrenal glands may be carried out.
What is the treatment?
The treatment of Cushing’s syndrome depends on the underlying cause. If you are on a long-term course of corticosteroid drugs, your doctor may reduce your dosage or, if possible, discontinue the treatment. However, you should not stop taking corticosteroid drugs without first consulting your doctor.
If the cause is a tumour in one of the adrenal glands, your doctor may initially prescribe drugs to lower corticosteroid levels. After that, it may be necessary to have the affected adrenal gland surgically removed.
If the adrenal glands have been overstimulated by a pituitary tumour, the tumour may be surgically removed. In most cases, the surgery is successful but radiotherapy or drug treatment are sometimes necessary to destroy any remaining abnormal cells.
You may need to take small doses of corticosteroid drugs for several months after surgery until your adrenal gland or glands adapt and produce normal amounts of hormones. The symptoms of Cushing’s syndrome should then improve gradually. In rare cases, if both adrenal glands are removed, you will need corticosteroid drugs for life.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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