Known also as hypercortisolism, the Cushing’s syndrome is a collection of signs and symptoms caused by long term exposure to high levels of cortisol.
The Cushing’s syndrome can be caused by diseases that will cause excess cortisol production, CRH levels or ACTH (adrenocorticotropic hormone). Taking glucocorticoid drugs could also cause the Cushing’s syndrome.
The Cushing’s syndrome should not be confused with Cushing’s disease or Cushing’s triad which are completely different things. But the Cushing’s disease can cause the Cushing’s syndrome. Cushing’s disease is caused by excess growth or a tumor of the pituitary gland.
In the case of Cushing’s disease, the pituitary gland releases too much ACTH (adrenocorticotropic hormone) which then causes the Cushing’s disease. It is one of the most common causes of Cushing’s syndrome.
Rapid weight gain and central obesity are the most common symptoms of Cushing’s syndrome. Common symptoms might also include buffalo hump, moon face and fat pads along the collarbone.
Other symptoms might include hirsutism, mucous membranes, excess sweating, thinning of the skin, purple or red striae, and dilation of capillaries. The excess cortisol might also cause impotence in men, insomnia, reduced libido, insomnia, infertility in women and inhibited aromatase. Depression, attention and memory dysfunctions are cognitive conditions often associated with Cushing’s syndrome. Diabetes mellitus, osteoporosis and hypertension are also symptoms of Cushing’s syndrome.
There two types of causes for the Cushing’s syndrome, exogenous and endogenous. The most common exogenous cause is the administration of glucocorticoids. As for the endogenous Cushing’s syndrome, 70% of the cases are caused by Cushing’s disease.
So, how does it work? Well. It’s pretty simple. The pituitary gland sits just below the hypothalamus in the brain. The CRH (corticotropin-releasing hormone) is released by the PVN (paraventricular nucleus) of the hypothalamus. The CRH stimulates the pituitary gland to release ACTH (adrenocorticotropin). Then the ACTH travels through the blood to the adrenal gland to stimulate the release of cortisol. Abnormally high levels of cortisol might cause a negative feedback on the pituitary gland which might lead to a decreased amount of ACTH from the pituitary gland.
When doctors suspect Cushing’s syndrome either a 24 hour urinary measurement of cortisol is performed or a dexamethasone suppression test. When any of the tests are positive MRI of the pituitary gland and CT scanning of the adrenal gland are performed to detect any adenomas or incidentalomas in the pituitary or adrenal gland. Many times the tumors causing the Cushing’s syndrome are very small, less than 2mm and difficult to detect.
Most cases of Cushing’s syndrome are iatrogenic (due to corticosteroid medications) used to treat arthritis, asthma or other inflammatory condition. In those cases the treatment stopping or tapering off the medication that causes the symptoms.
Surgical removal is performed when adrenal or pituitary adenoma is detected. Steroid replacement postoperatively is necessary in most patients until the tissue recovers. If the patient are unwilling or unsuitable for surgery several drugs can be used to inhibit the cortisol synthesis but the effectiveness is limited.
As the decision of the patient is important to ask for the help of a doctor for a better understanding of the disease that could help the patient make the best decision.