Addison’s disease, also known as adrenal insufficiency, occurs when underactive adrenal glands don’t produce enough of the hormone cortisol and, in some cases, the hormone aldosterone. The potentially life-threatening disease affects both sexes and can begin at any age. Approximately four in every 100,000 people have adrenal insufficiency.
In most cases, adrenal insufficiency results from the destruction of the adrenal cortex, the outer layer of the adrenal glands. This disorder is know as primary adrenal insufficiency and is usually an autoimmune condition in which a patient’s immune system uses its antibodies to attack and destroy its own adrenal glands. Some less common causes of primary adrenal insufficiency include: Tuberculosis, adrenal tumors and other infections.
Secondary adrenal insufficiency is a more common form of adrenal insufficiency and is due to a lack of adrenocorticotropin (ACTH). ACTH is a hormone secreted by the pituitary gland, which, in turn, stimulates the adrenal glands to produce cortisol, but not aldosterone. The lack of ACTH leads to a drop in the production of adrenal cortisol.
Abruptly ending treatment with glucocorticoids, such as prednisone is usually the most frequent cause of secondary adrenal insufficiency. Other causes of secondary adrenal insufficiency are less frequent and include: pituitary tumors, history of pituitary surgery, radiation
Symptoms of Adrenal Insufficiency
If the symptoms of adrenal insufficiency are left untreated, they may lead to severe nausea, vomiting, abdominal pain, and low blood pressure. Known as an adrenal crisis, its causes also include stressful events such as surgery, trauma, and infection. If an adrenal crisis is not treated, it can be fatal.
Diagnosis of Adrenal Insufficiency
Diagnosing adrenal insufficiency consists mainly of a series of blood tests to measure levels of cortisol in your system. If the levels are insufficient, CT and MRI scans may be used to determine whether the exact cause can be attributed to adrenal insufficiency.
To measure cortisol response, your doctor may order a stimulation test with either of the following:
Cortrosyn (ACTH) test
- Usually done in the laboratory
- Total duration of one hour
Insulin tolerance test
- Done in Endocrinology outpatient department
- Total duration of two hours
Once it has been determined whether the adrenal insufficiency is primary or secondary, your doctor may order an imaging (radiology) test for either your adrenal glands (usually a CT scan) or your pituitary gland (usually an MRI scan).
Treatment of Adrenal Insufficiency
Treatment of adrenal insufficiency involves replacing the insufficient hormones.
Treatment usually starts with either hydrocortisone or prednisone, corticosteroids that are used as cortisol replacements. The medication is taken orally once or twice a day. Adrenal treatment may also include taking fludrocortisone, a drug that replaces aldosterone, if needed. Patients should double the dose during stress, such as illness with fever, and let other health providers know about their condition prior to any procedures or surgeries. Patients who can’t take the oral medication due to nausea or vomiting should get medical attention and immediately receive injectable steroids to avoid adrenal crisis.
Since adrenal insufficiency is life-threatening, patients should wear a medical alert bracelet or necklace at all times.