context: You have two adrenal glands, one above each kidney. They make important hormones that your body uses for some of its most basic functions. When they don't make enough of those hormones, you have a condition called adrenal insufficiency, also called adrenocortical insufficiency or hypocortisolism. Your adrenal glands have two jobs. The first is to make adrenaline, a hormone your body creates in times of stress. But the more important job is making two steroid hormones, cortisol and aldosterone. Cortisol also helps your body deal with stress. Among its jobs: Controls your blood pressure and your heart rate Controls how your immune system deals with viruses, bacteria, and other threats Puts more sugar in your bloodstream to give you more energy Adjusts how your body breaks down carbohydrates, proteins, and fats Aldosterone keeps the sodium and potassium in your blood balanced, which helps control your blood pressure and the balance of fluids in your body. When there's not enough of these hormones, your body has trouble with these basic functions. That causes the symptoms of adrenal insufficiency -- fatigue, muscle weakness, low appetite, weight loss, and belly pain, among others. You can have either primary, secondary or tertiary adrenal insufficiency. Primary adrenal insufficiency is when your adrenal glands are damaged and can't make the cortisol you need. They also might not make enough aldosterone. This condition is often called Addison's disease. Secondary adrenal insufficiency is more common than Addison's disease. The condition happens because of a problem with your pituitary gland, a pea-sized bulge at the base of your brain. It makes a hormone called adrenocorticotropin ( ACTH). This is the chemical that signals your adrenal glands to make cortisol when your body needs it. If your adrenal glands don't get that message, they may eventually shrink. Tertiary starts in the hypothalamus, which is a small area located near the pituitary. It makes a hormone called corticotropin-releasing hormone ( CRH) which tells the pituitary to make ACTH. When the hypothalamus is not making enough CRH, then it affects the pituitary's ability to produce ACTH , in turn keeping the adrenal glands from producing enough cortisol. Adrenal Insufficiency is quite complicated and can be caused by about 50 different conditions. The most common cause of Addison's disease today is an autoimmune problem, when your immune system malfunctions and attacks and damages your own body, in this case, your adrenal glands. Less common causes include: Fungal infections Tuberculosis A virus called cytomegalovirus, which is more common in people with AIDS Cancer that has spread from another part of the body Secondary adrenal insufficiency starts with damage to your pituitary gland or to the part of your brain that controls it, called the hypothalamus. Conditions that can damage these parts include: Some inflammatory diseases Cysts or tumors in your pituitary gland Surgery or radiation to treat those tumors If you've had surgery for a condition called Cushing's syndrome, you're even more likely to get secondary adrenal insufficiency. In this procedure, surgeons remove pituitary gland tumors that were making extra ACTH. You'll have to take hormone replacements until your body is able to make normal amounts of cortisol on its own. You can also get secondary adrenal insufficiency because of drugs called glucocorticoids, such as cortisone, hydrocortisone, prednisone, prednisolone, and dexamethasone. People take these medicines regularly to treat diseases such as rheumatoid arthritis, ulcerative colitis, or asthma. The drugs act like cortisol in your body. When your body detects them, it senses that cortisol is present, so your pituitary gland doesn't make as much ACTH to prompt your adrenal glands to make more. How long the effect lasts depends on how much of the medication you take and for how long. You shouldn't have a problem if you take them for just a few days. Tertiary adrenal insufficiency is the result of damage to the hypothalamus which can affect its ability to produce CRH. The most common causes for this are brain tumors, trauma to the base of the skull or sudden withdrawal from long-term use of exogamous steroids.