Cushing's Disease

What causes it?

When a tumour on the pituitary produces adrenocorticotropic hormone (ACTH). This hormone stimulates the adrenal glands causing them to produce excess cortisol. It can also be caused by a hormone on the adrenal gland.

What are the symptoms

Common features include significant weight gain, specifically around the trunk area (arms and legs remain unchanged). High blood pressure (hypertension) and mood changes. These symptoms are not always present.

Image courtesy of (https://courses.stu.qmul.ac.uk/smd/kb/resources/endocrinologyresource/images/q4ptcush.jpg)

 Diagnosis

The symptoms for this disease do not always appear and those that do are similar symptoms to a range of other diseases. This means that Cushings is not always initially diagnosed.

The most common test used for an initial diagnosis of Cushing's is a Cortisol measurement. This measurement is taken either from the saliva or the urine. The method used to detect whether there is too much cortisol in the blood involves giving the patient a tablet which mimics cortisol (dexamethasone). If the body is regulating cortisol efficiently then the cortisol levels will decrease. This will not be the case if the patient has Cushings. 

Although a negative result with this test indicates that Cushing's Disease may be present it still can not be confirm as elevated cortisol levels are symptoms of other disorders e.g depression. These need to be ruled out first and this can be done by adminsitering treatment for them and seeing if cortisol levels normalise. If they do then Cushings Disease is the diagnosis.

 Treatment

The most effective treatment is the removal of the tumour on the pituitary or adrenal gland which is causing the elevated cortisol levels. If surgery is not a viable option then a comination of radio therapy and cortisol releasing drugs. If the adrenal glands have to removed then the patient will need to take cortisol-like tablets and salt balancing tablets everyday for the rest of their life.