CUSHING’S SYNDROME
WHAT IS CUSHING’S SYNDROME?
Cushing’s syndrome is an endocrine disorder caused by an excess of cortisol in the blood produced by a neuroendocrine tumour, usually a benign tumour located in the pituitary gland. The tumour cells may secrete either cortisol or ACTH (the hormone that causes cortisol secretion), and though they may do so in other parts of the body, such as the lung, it is much rarer. The most common cause of this condition is the treatment with high doses of cortisone for months or years.
WHAT ARE THE SYMPTOMS?
The symptoms of Cushing’s syndrome include changes in fat distribution, moon face, truncal obesity, a pad of fat in the neck and above the clavicles, thin and fragile skin, stretch marks (striae) on the belly and inner thighs, marks of hematomas, increased pigmentation, muscle atrophy in the arms and legs, increased body hair, menstrual disorders in women, hypertension, decalcification of bones and diabetes. There are usually psychiatric symptoms such as mood changes, depression, and memory disorders.
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Cushing’s syndrome symptoms
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Striae due to Cushing’s syndrome
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Moon face due to Cushing’s syndrome
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Cushing’s syndrome as seen up front
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Cushing’s syndrome as seen from behind
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HOW IS DIAGNOSIS MADE?
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Cushing’s syndrome is suspected due to the appearance of patients and then confirmed by analytical studies of cortisol levels in urine over 24 hours. Once the syndrome has been confirmed, its cause must be sought through MRI brain studies to rule out a tumour in the pituitary gland. Some ACTH-producing tumours are very small and can be found only after repeated examinations. If nothing is found in the brain it may be necessary to study the adrenal capsules or find other sources, such as infrequent tumours in the pancreas or lung, but these cases are extremely rare.
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Pituitary gland tumour
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TREATMENT
The objective is to bring the blood levels of cortisol and ACTH back to normal. There are some drugs to try to control the effects of cortisol, such as ketokonazol, but they are only temporary measures until the cause is found and a correction applied. The most common cause is a tumour in the pituitary gland, which would require surgery, in most cases though the nose (transphenoidal approach), though nowadays the approach is usually done endoscopically. With larger tumours, however, an intervention through the top of the head (craniotomy) may be necessary.
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Transnasal endoscopic approach to pituitary gland tumour
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Craniotomy to remove a pituitary gland tumour
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In some cases radiotherapy is used to supplement the treatment. More commonly, however, radiosurgery is performed, because it enables the treatment of tumour remains or recurrences. If the tumour is close to the optic nerves, however, fractionated stereotactic radiotherapy techniques can be used. They allow greater accuracy while minimising the amount of damage to the optic nerves.
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Radiosurgery in the treatment of pituitary tumours
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When the problem lies in the adrenal glands, the tumour in them must be removed. They are long and complex interventions that carry associated risks to be discussed with the medical team.
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Pituitary gland and adrenal glands
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In the very rare case that Cushing’s syndrome has been produced by a lung tumour, the tumour is usually malignant and will require a treatment consisting of a combination of surgery (when possible), radiotherapy and chemotherapy.
WHAT ARE THE RESULTS?
If the cause is cortisone ingestion for months, with the withdrawal of the medication the changes are reversed, but very slowly and only partially. In the case of pituitary tumours it is not always possible to completely remove the tumour, especially with large tumours, and in these cases combined therapies and even conventional radiotherapy may be necessary. In some cases it is also necessary to block the effects of cortisol with other drugs, such as ketokonazol. When the intake of corticosteroids has persisted for months, a significant amount of time will be needed before cortisol production from the patient is fully recovered.