Adrenal insufficiency: Clinical

Adrenal insufficiency is a condition in which the adrenal glands don’t produce enough adrenal hormones - particularly cortisol, but sometimes aldosterone can be deficient as well.

Cortisol production is normally under the control of the hypothalamus and pituitary. The hypothalamus secretes corticotropin-releasing hormone, or CRH, which makes the pituitary gland secrete adrenocorticotropic hormone, or ACTH.

ACTH then stimulates the release of cortisol from the adrenal glands. Aldosterone, on the other hand, is the final product of a physiological chain called the renin-angiotensin-aldosterone system, or RAAS for short.

Renin is produced by the kidneys, so aldosterone production is actually independent of hypothalamic and pituitary stimulation. This is important, because adrenal insufficiency actually comes in three distinct flavors.

First, there’s primary adrenal insufficiency, or Addison’s disease, when there’s a problem with the adrenal glands themselves. In this case, both cortisol and aldosterone production are deficient.

The most common cause for primary adrenal insufficiency in high income countries is autoimmune destruction of the adrenal gland. Another common cause can be due to tuberculosis, HIV, or disseminated fungal infections.

Finally, bilateral adrenal metastases from cancer somewhere else in the body, like the lungs, breast, or colon, can also cause adrenal insufficiency.