Diagnosis

In diagnosing Addison’s disease it is very important to distinguish this disease from secondary adrenal insufficiency. The difference is that in Addison’s disease the adrenal glands are damaged and therefore produce too few hormones, whereas in the secondary disorder the adrenal glands are intact but not sufficiently stimulated to produce hormones. If Addison’s disease is suspected, blood tests are performed to check hormone levels.

A sodium deficiency and an elevated potassium concentration in the blood are suspected to cause a disturbance of the adrenal glands. In addition to the usual blood parameters, the amount of cortisol in the blood and the amount of ACTH are determined. ACTH is secreted by the pituitary gland in the brain and stimulates the adrenal glands to produce hormones.

If the cortisol level is reduced although there is enough or even too much ACTH in the blood, this indicates Addison’s disease. A so-called ACTH stimulation test can also be performed. Here ACTH is injected intravenously, which would trigger increased cortisol production in healthy individuals with functioning adrenal glands.

In Addison’s disease, however, this is not the case due to the damaged adrenal glands. In adrenal insufficiency, the cortisol levels in the blood are reduced. The cortisol present in the blood does not allow us to determine the cause.

If one wants to know where the problem of the dysfunction lies, one must determine the ACTH value. This is a hormone from the pituitary gland, which naturally stimulates the adrenal gland to produce cortisol. Based on the ACTH value, it is then possible to find out whether the problem lies in the adrenal gland or the pituitary gland, i.e. whether primary or secondary adrenal insufficiency exists.

In primary insufficiency, the adrenal gland no longer functions properly, but the pituitary gland continues to try to stimulate it by secreting ACTH. As a result, ACTH is present in increased quantities. Furthermore, the levels of aldosterone and DHEAS are determined, which are also hormones that are produced in the adrenal gland.If the disorder is located in the pituitary gland, the ACTH value is reduced. The pituitary gland can no longer perform its function and the hormones it produces can hardly be detected in the blood.