Question: What are the symptoms of adrenal insufficiency?
Answer: The most common symptoms of adrenal insufficiency are

chronic, or long-lasting, fatigue
muscle weakness
loss of appetite
weight loss
abdominal pain

Other symptoms of adrenal insufficiency can include

nausea
vomiting
diarrhea
low blood pressure that drops further when you stand up, causing dizziness or fainting
irritability and depression
joint pain
craving salty foods
hypoglycemia, or low blood glucose
irregular or no menstrual periods
loss of interest in sex

People with Addison’s disease may also have darkening of their skin. This darkening is most visible on scars; skin folds; pressure points such as the elbows, knees, knuckles, and toes; lips; and mucous membranes such as the lining of the cheek.

Because symptoms of adrenal insufficiency come on slowly over time, they may be overlooked or confused with other illnesses. Sometimes symptoms appear for the first time during adrenal crisis. If you always feel tired, weak, or are losing weight, ask your health care professional if you might have adrenal insufficiency. Early treatment can help avoid an adrenal crisis.
Question: What causes adrenal insufficiency?
Answer: Different types of adrenal insufficiency have different causes. The most common cause of adrenal insufficiency overall is suddenly stopping corticosteroids after taking them for a long time.

Addison’s disease

Damage to the adrenal glands in Addison’s disease is usually caused by autoimmune disease—when your immune system attacks your body’s own cells and organs. In developed countries, autoimmune disease causes 8 or 9 of every 10 cases of Addison’s disease.4

Certain infections can also cause Addison’s disease. Tuberculosis (TB) can damage the adrenal glands and used to be the most common cause of Addison’s disease. As treatment improved over the years, TB became a much less common cause. People with HIV/AIDS, whose weakened immune systems can’t fight off infections that could cause Addison’s disease, are also at risk.

Less common causes of Addison’s disease are

cancer cells in the adrenal glands
surgical removal of the adrenal glands to treat other conditions
bleeding into the adrenal glands
genetic disordersthat affect the way the adrenal glands develop or function
certain medicines, such asantifungalmedicines or etomidate, a type ofgeneral anesthesia

Secondary adrenal insufficiency

Anything that affects the pituitary’s ability to make ACTH can cause secondary adrenal insufficiency. The pituitary makes many different hormones, so ACTH may not be the only hormone that’s lacking.

Causes of secondary adrenal insufficiency include

autoimmune disease
pituitary tumors or infection
bleeding in the pituitary
genetic diseases that affect the way the pituitary gland develops or functions
surgical removal of the pituitary to treat other conditions
traumatic brain injury

Tertiary adrenal insufficiency

The most common cause of tertiary adrenal insufficiency is suddenly stopping corticosteroids after taking them for a long time. Prescription doses of corticosteroids can cause higher levels of cortisol in your blood than your body normally makes. High levels in your blood for a long time cause the hypothalamus to make less CRH. Less CRH means less ACTH, which in turn causes the adrenal glands to stop making cortisol.

Once you stop taking corticosteriods, your adrenal glands may be slow to start working again. To give them time to start making cortisol again, your doctor will gradually reduce your dose over a period of weeks or even months. Even so, your adrenal glands might not begin to work normally for many months. Your doctor should watch you carefully for symptoms of adrenal insufficiency.

Tertiary adrenal insufficiency can also occur after Cushing’s syndrome is cured. Cushing’s syndrome is a hormonal disorder caused by high levels of cortisol in the blood for a long time. Sometimes Cushing’s syndrome is caused by tumors, usually noncancerous, in the pituitary or adrenal glands that make too much ACTH or cortisol. Once the tumors are surgically removed, the source of excess ACTH or cortisol is suddenly gone. Your adrenal glands may be slow to start working again.