Endocrinology : Pathophysiology of Addison"s Disease :

Pathophysiology of Addisons Disease :

Addison's disease is caused by damage to the  adrenal glands, resulting in not enough production  of the hormone cortisol and, often, not enough aldosterone as well. 

These hormones have effects that influence  virtually every organ and tissue in the body.

Parts of the adrenal glands

The adrenal glands have mainly two parts :

The interior (medulla) produces adrenaline-like hormones.

The outer layer (cortex) produces a group of hormones called corticosteroids.

Corticosteroids include:

Glucocorticoids.

These hormones, which include cortisol, influence the body's ability to convert food into energy, play a role in  immune system's inflammatory response and help the body respond to stress.

Mineralocorticoids.

These hormones, which include aldosterone, maintainr body's balance of sodium and potassium to keep blood pressure normal.

Causes Of Addison”s Disease :

Primary adrenal insufficiency :

When the cortex is damaged and doesn't produce enough adrenocortical hormones, the condition is called primary adrenal insufficiency.

This is most commonly the result of the body attacking itself (autoimmune disease).

For unknown reasons,the body”s immune system views the adrenal cortex as foreign, something to attack and destroy.

People with Addison's disease are more likely than others to have another autoimmune disease as well.

Other causes of adrenal gland failure may include:

Tuberculosis

Other infections of the adrenal glands

Spread of cancer to the adrenal glands

Bleeding into the adrenal glands.

Secondary adrenal insufficiency

The pituitary gland makes a hormone called adrenocorticotropic hormone (ACTH).

ACTH in turn stimulates the adrenal cortex to produce its hormones.

Benign pituitary tumors, inflammation and prior pituitary surgery are common causes of not producing enough pituitary hormone.

Too little ACTH can lead to too little of the glucocorticoids and androgens normally produced by your adrenal glands, even though adrenal glands themselves aren't damaged.

This is called secondary adrenal insufficiency.

Mineralocorticoid production is not affected by too little ACTH.

Most symptoms of secondary adrenal insufficiency are similar to those of primary adrenal insufficiency.

However, people with secondary adrenal insufficiency don't have hyperpigmentation and are less likely to have severe dehydration or low blood pressure.

They're more likely to have low blood sugar.

A temporary cause of secondary adrenal insufficiency occurs when people who take corticosteroids (for example, prednisone) to treat chronic conditions, such as asthma or arthritis, stop taking the corticosteroids all at once rather than tapering off.