[[Image:adrenalatrophy123456.jpg|left|thumbnail|Adrenal Atrophy; source: U.S. National Toxicology Program - available at: https://ntp.niehs.nih.gov/nnl/endocrine/adrenal/cxzatrophy/index.htm]]
The normal physiology of adrenal atrophy can be understood as follows:
===Primary adrenal insufficiency===
Adrenal glands produce hormones that help regulate your metabolism, immune system, blood pressure, response to stress and other essential functions. The glands are composed of two parts:
Primary adrenal insufficiency, which can be acute or chronic, may be caused by the anatomic destruction of the gland. This destruction can have various causes, including [[tuberculosis]] (TB) or fungal infection, other diseases infiltrating the adrenal glands, and hemorrhage. However, the most frequent cause is idiopathic atrophy, which is probably autoimmune in origin.
*The adrenal cortex is the outer region and also the largest part of an adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones.
*The adrenal medulla is located inside the adrenal cortex in the center of an adrenal gland. It produces “stress hormones,” including epinephrine.
Primary adrenal insufficiency also may be caused by metabolic failure (eg, insufficient hormone production). This failure may be a result of congenital adrenal hyperplasia, enzyme inhibitors (e.g., [[metyrapone]]), or cytotoxic agents (e.g., [[mitotane]]).
[[Image:adrenalatrophy123456.jpg|left|thumbnail|Adrenal Atrophy; source: U.S. National Toxicology Program - available at: https://ntp.niehs.nih.gov/nnl/endocrine/adrenal/cxzatrophy/index.htm]]
Primary adrenocortical insufficiency is rare and it occurs at any age. The male-to-female ratio is 1:1.
===Secondary adrenal insufficiency===
Secondary adrenal insufficiency may be caused by [[hypopituitarism]] due to hypothalamic-pituitary disease, or it may result from suppression of the hypothalamic-pituitary axis by exogenous steroids or endogenous steroids (i.e., [[tumor]]).
Secondary adrenocortical insufficiency is relatively common. Extensive therapeutic use of steroids has greatly contributed to increased incidence.
===Acute adrenocortical insufficiency===
Adrenal crisis may result from an acute exacerbation of chronic insufficiency, usually caused by sepsis or surgical stress. Acute adrenal insufficiency also can be caused by adrenal hemorrhage (e.g., usually septicemia-induced [[Waterhouse-Friderichsen syndrome]] - [[fulminant meningococcemia]]) and anticoagulation complications.
[[Steroid]] withdrawal is the most common cause of acute adrenocortical insufficiency, and it almost exclusively causes a glucocorticoid deficiency.
<div align="center">
<gallery heights="175" widths="175">
Image:Adrenal atrophy 1.JPG|Adrenal atrophy [http://www.gfmer.ch/000_Homepage_En.htm Image courtesy of Geneva Foundation for Medical Education and Research]
Image:Adrenal atrophy 2.JPG|Adrenal atrophy [http://www.gfmer.ch/000_Homepage_En.htm Image courtesy of Geneva Foundation for Medical Education and Research]
Image:Adrenal atrophy 3.JPG|Adrenal atrophy [http://www.gfmer.ch/000_Homepage_En.htm Image courtesy of Geneva Foundation for Medical Education and Research]
Image:Adrenal atrophy 4.JPG|Adrenal atrophy [http://www.gfmer.ch/000_Homepage_En.htm Image courtesy of Geneva Foundation for Medical Education and Research]
Image:Adrenal atrophy 5.JPG|Adrenal atrophy [http://www.gfmer.ch/000_Homepage_En.htm Image courtesy of Geneva Foundation for Medical Education and Research]
The normal physiology of adrenal atrophy can be understood as follows:
Adrenal glands produce hormones that help regulate your metabolism, immune system, blood pressure, response to stress and other essential functions. The glands are composed of two parts:
The adrenal cortex is the outer region and also the largest part of an adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones.
The adrenal medulla is located inside the adrenal cortex in the center of an adrenal gland. It produces “stress hormones,” including epinephrine.
