Internal Medicine

Cushing threshold

definition

The Cushing threshold describes the amount of glucocorticoids (e.g. cortisone) that is given in the form of a drug and that triggers the clinical picture of Cushing's disease. Since it is not a real Cushing syndrome, it is called Cushing syndrome. The way this disease is triggered by a drug is also known as iatrogenic (literally "triggered by the doctor"). In this disease, an excessive dose of glucocorticoids leads to a typical external appearance with certain specific recognition features. These include, among other things, trunk obesity, a bull's neck and a full moon face as well as virilization, i.e. masculinization.

Read more at: Cushing Syndrome

Threshold dose

The threshold dose for Cushing's disease depends on many factors. This includes the type of medication administration, since an intravenous intake of the medication has different consequences than, for example, an administration in the form of a skin ointment. Another factor is the individual response to the medication. This means that everyone reacts differently to a drug. Furthermore, the drugs also differ from each other.

Cortisone, for example, has the highest Cushing threshold dose at around 40 mg per day in men. Women have a slightly lower Cushing threshold due to different body metabolic conditions. Before menopause, it is 25-30 mg per day, then 15 to 25 mg per day. This means that if more than 40 mg is given per day, the clinical picture of Cushing's disease can be triggered.

In comparison, the threshold dose for prednisolone administration is only around 7.5 mg per day and is therefore significantly lower than that of cortisone. The lowest threshold dose of frequently used drugs is betamethasone with 1 mg per day.

Find out all about the topic here: Cushing's disease.

Threshold dose in children

In the case of children, care must be taken that they have different threshold doses for different preparations due to different physical conditions. Unfortunately, there are also many childhood diseases that require the use of glucocorticoids as a therapy. Therefore, special care must be taken to ensure that nothing at such an early age will trigger Cushing's syndrome from an overdose of glucocorticoids.

The Cushing threshold dose for the preparation prednisone in children is 6 mg per m² body surface per day. However, this amount should only be seen as a guideline for children, as the processing of the preparation in the body can vary from child to child.

What do you need the Cushing threshold for?

Many different diseases are treated with the help of glucocorticoids. These are primarily chronic diseases that will accompany the person affected for the rest of their lives.
Common examples of this are:

the lung disease COPD
Rheumatoid arthritis
or
Autoimmune diseases like
- multiple sclerosis
  or
- Lupus erythematosus.

It is also more and more common for people to suffer from several of these diseases at the same time and accordingly also take therapeutic glucocorticoids for various diseases on a regular basis.

It is therefore very important to note that the high use of glucocorticoids does not result in any additional new and stressful clinical picture. The Cushing threshold is therefore used as an aid to relieve the patient with his illnesses instead of adding to the burden. Doctors can use this as a guide when prescribing glucocorticoids so as not to cause unnecessary side effects.

What happens if the Cushing threshold is exceeded?

If the Cushing threshold is exceeded once, no direct consequences are usually to be expected. Since the clinical picture of Cushing's syndrome is a chronic disease, it is unlikely that symptoms will occur if the dose is exceeded once.

It becomes problematic if the Cushing threshold is exceeded over the long term. This greatly increases the likelihood of developing Cushing's syndrome with hypercortisolism. Depending on how this is manifested, drug therapy to counteract the disease should be considered. So-called adrenostatic drugs can be given, which block the synthesis of cortisol in the body. In all cases, however, the cortisone therapy should be reduced as soon as it becomes apparent that the Cushing's threshold has been exceeded.

For more information, see: typical symptoms of Cushing's syndrome