Synonyms in a broader sense
English: Cushing’s syndrome
- Hypercortisolism
- Cushing’s disease
- Endocrine and exocrine Cushing’s syndrome
Definition
In Cushing’s syndrome (Cushing’s disease) there is too much cortisol in the body. Cortisol is a hormone that is produced by the body itself, but is also used as a drug, for example to suppress inflammatory reactions. Overactivity of the pituitary gland (hypophysis) due to a tumour or a tumour of the adrenal gland can lead to the body’s own increased production and release of cortisol.
Regulation processes in the body
Cortisol is normally produced in the body in response to the signal of ACTH and released into the bloodstream. The hormone chain begins with CRH, which is produced in the hypothalamus, a specific region of the brain. The CRH (corticotropin releasing hormone or corticoliberin) stimulates the pituitary gland to release ACTH into the bloodstream.
ACTH (adrenocorticotropic hormone) is a hormone produced by the pituitary gland and also released into the bloodstream. In the bloodstream, this stimulating hormone reaches the adrenal gland and promotes its activity. The activity of the adrenal glands eventually leads to the production of cortisol.
If more cortisol is now produced in the body and is found in the blood, the formation and release of CRH and ACTH decreases. Cortisol therefore has an inhibitory effect on the formation of these two hormones. This mechanism is called negative feedback and since cortisol acts on two hormones, this particular mechanism is called double negative feedback.
Cushing’s syndrome due to cortisone
Cushing’s syndrome is caused by too much cortisone in the body. Cortisone is a very important hormone produced in the human body. It controls various signalling pathways in the body, which are particularly important in times of stress or hunger and usually lead to an increase in blood sugar levels.
For this reason, cortisone is also used as a drug for various chronic diseases. However, too large an amount of cortisone leads to side effects such as fat redistribution, osteoporosis or the development of a blood sugar disease. If these symptoms occur together, they are grouped together under Cushing’s syndrome.
The increased cortisone can be caused either by excessive medication or by overproduction of the body itself. The pituitary gland, a part of the brain, and the adrenal cortex are particularly involved in the production of cortisone. If one of these organs sends out too strong signals for cortisone production, the amount in the blood increases and Cushing’s syndrome develops. This is most often due to a benign tumour disease of these organs.
Forms of Cushing’s syndrome
An excess of cortisol in the body can be caused in two ways: On the one hand, the cortisol in the body is elevated when it is administered externally as a drug for therapeutic purposes, as may be necessary in a chronic inflammatory reaction (for example in rheumatic diseases). This form of the disease is also known as exogenous Cushing’s syndrome. On the other hand, it is possible that the body itself produces too much cortisol and releases it into the bloodstream, as is the case in endogenous Cushing’s syndrome.
There are various subgroups in this form of the disease, which differ in where the overproduction of the hormone takes place. If an adrenal gland tumour is responsible for the formation of too much cortisol, this is known as adrenal Cushing’s syndrome. When the pituitary gland secretes too much ACTH, the adrenal gland produces too much cortisol; this dysregulation of hormone production is called Cushing’s disease.
In most cases there is a small hormone-producing tumour in the pituitary gland, which is responsible for the excessive ACTH production. ACTH can also be produced by tumours that lie outside the pituitary gland, such as a lung tumour. In these cases, one speaks of ectopic formation of ACTH. Ectopic means that ACTH is not formed in the place where it would be formed under normal conditions in the body. The different forms of Cushing’s syndrome and their subgroups are once again clearly illustrated in the following table:
- Exogenous Cushing’s syndrome caused by medication
- Endogenous Cushing’s syndrome (Cushing’s disease) a. adrenal Cushing’s syndrome b. central Cushing’s syndrome, also known as Cushing’s disease c. ectopic ACTH production
