Addison's Disease: Description:
Also called as chronic adrenocortical insufficiency.
Adrenocortical insufficiency usually as the result of idiopathic atrophy or destruction of both adrenal glands by tuberculosis, an autoimmune process, or other diseases; characterized by fatigue, decreased blood pressure, weight loss, increased melanin pigmentation of the skin and mucous membranes, anorexia, and nausea or vomiting; without appropriate replacement therapy, it can progress to acute adrenocortical insufficiency
Alternative Names: Hyposupradrenalism, morbus Addisonii, and addisonian syndrome.
The adrenal glands are small organs located on top of each kidney. They consist of an inner layer called the adrenal medulla and an outer layer called the adrenal cortex. Each layer produces several different hormones that control many body systems. Hormone production is regulated by interactions between the hypothalamus, the pituitary gland, and the adrenal glands. If any part of their signaling and feedback system is not working, it can cause major disruptions and illness within the body. Primary adrenal insufficiency, also called Addison's disease, affects the levels of both cortisol and aldosterone. It is caused by underactive or damaged adrenal glands. Secondary adrenal insufficiency is the result of a pituitary dysfunction and typically affects only cortisol production.
Addison's disease affects about 1 in 100,000 people. Most cases are caused by the gradual destruction of the adrenal cortex, the outer layer of the adrenal glands, by the body's own immune system. About 70 percent of reported cases of Addison's disease are caused by autoimmune disorders, in which the immune system makes antibodies that attack the body's own tissues or organs and slowly destroy them. Adrenal insufficiency occurs when at least 90 percent of the adrenal cortex has been destroyed. As a result, often both glucocorticoid (cortisol) and mineralocorticoid (aldosterone) hormones are lacking. Sometimes only the adrenal gland is affected, as in idiopathic adrenal insufficiency; sometimes other glands also are affected, as in the polyendocrine deficiency syndrome.
The symptoms associated with adrenal insufficiency are often vague and nonspecific. They may emerge slowly, first appearing during times of stress, then increasing in intensity over a period of several months.
Causes and Risk Factors:
- Dehydration with Addison's disease.
- Diarrhea or constipation.
- Dizziness and fainting.
- Joint and muscle aches.
- Low blood pressure.
- Muscle weakness.
- Loss of appetite.
- Weight loss.
Primary adrenal insufficiency occurs when the outer layer of the adrenal gland is damaged and does not produce enough hormones. This is usually caused by an autoimmune disease in which the body's own immune system attacks the adrenal glands. Normally, antibodies produced by the immune system help protect the body against viruses, bacteria and other foreign substances. An autoimmune disease is when your immune system produces antibodies that attack your body's tissues and/or organs.
Other causes of adrenal gland failure are:
Secondary adrenal insufficiency occurs when you have another condition that causes the adrenal gland to fail to produce enough hormones. It can be caused by a diseased pituitary gland. The pituitary gland makes a hormone called adrenocorticotropic hormone (ACTH) that stimulates the adrenal glands to produce their hormones. If the pituitary gland is unable to produce enough ACTH, the adrenal glands will not be stimulated to produce their hormones.
Your doctor will ask you about your medical history and your symptoms. He or she may also perform laboratory tests to determine whether you have Addison's disease:
Blood tests: Tests that measure the levels of sodium, potassium, cortisol and ACTH in your blood can help your doctor know whether an adrenal insufficiency is causing your symptoms. Your doctor can also use a blood test to see if an autoimmune disease is the possible cause of your Addison's disease.
ACTH: ACTH is a pituitary hormone that signals the adrenal glands to produce cortisol. This test is primarily ordered as a baseline test to evaluate whether or not the pituitary is producing appropriate amounts of ACTH. In a patient with adrenal insufficiency, low ACTH levels indicate secondary adrenal insufficiency, while high levels indicate primary adrenal insufficiency (Addison's disease). The ACTH test is often ordered along with the ACTH stimulation test.
ACTH Stimulation Test: This test involves measuring the level of cortisol in a patient's blood before and after an injection of synthetic ACTH. If the adrenal glands are functional, cortisol levels will rise in response to the ACTH stimulation. If they are damaged or non-functional, then their response to ACTH will be minimal. This rapid screening test may be ordered along with a baseline ACTH test and, if abnormal, may be followed with a 1 to 3 day prolonged ACTH stimulation test to help differentiate between primary and secondary adrenal insufficiency.
Aldosterone: Blood or urine aldosterone levels are measured to help diagnose Addison's disease - to determine whether the adrenal gland is producing aldosterone. If the levels are low, it is another indication that the patient may have a primary adrenal insufficiency.
Electrolytes: Electrolytes (Sodium, Potassium, Chloride and Carbon dioxide) are measured to help detect and evaluate the severity of an existing electrolyte imbalance and to monitor the effectiveness of treatment. Electrolytes may be affected by many conditions; with Addison's disease the sodium, chloride, and carbon dioxide levels are often low, while the potassium level may be very high.
BUN and Creatinine are tests done to monitor kidney function.
Glucose levels may be very low during an adrenal crisis. Glucose may be ordered in order to help monitor a patient during a crisis.
Occasionally used tests
Insulin-induced hypoglycemia test: Occasionally, a doctor will order this test to assist in the detection of adrenal insufficiency. Glucose and cortisol levels are measured at predetermined intervals after an injection of insulin is used to stress the pituitary gland. In healthy people, blood glucose levels fall and cortisol concentrations increase. In those with adrenal insufficiency, cortisol levels will remain low and glucose levels will fall, then recover slowly.
21-hydroxylase autoantibodies are sometimes ordered as part of the diagnostic process when autoimmune Addison's disease is suspected. They are considered a good marker of autoimmune Addison's disease but are not widely used at this time.
Renin: Renin activity is elevated in primary adrenal insufficiency because a lack of aldosterone causes increased renal sodium losses. This lowers blood sodium levels and decreases the amount of fluid in the blood (which lowers blood volume and pressure), which in turn stimulates renin production by the kidney.
X-rays may be used to look for calcification on the adrenal cortex that may be due to a tuberculosis infection.
CT (computerized tomography) or MRI (magnetic resonance imaging) scans are sometimes used to look at the size and shape of the adrenal glands and the pituitary. The adrenal glands can be enlarged with infections and cancers. With autoimmune diseases and secondary adrenal insufficiency, the adrenal glands are often normal or small in size.
If you receive an early diagnosis of Addison's disease, treatment may involve taking prescription corticosteroids. Because your body is not producing sufficient steroid hormones, your doctor may have you take one or more hormones to replace the deficiency. Cortisol is replaced using hydrocortisone (Cortef), prednisone or cortisone acetate. Fludrocortisone (Florinef) replaces aldosterone, which controls your body's sodium and potassium needs and keeps your blood pressure normal.
You take these hormones orally in daily doses that mimic the amount your body normally would make, thereby minimizing side effects. If you're facing a stressful situation, such as an operation, an infection or a minor illness, your doctor will suggest a temporary increase in your dosage. If you're ill with vomiting and can't retain oral medications, you may need corticosteroid injections.
In addition, your doctor may recommend treating androgen deficiency with an androgen replacement called dehydroepiandrosterone. Some studies indicate that, for women with Addison's disease, androgen replacement therapy may improve overall sense of well-being, libido and sexual satisfaction.
Keep an ongoing relationship with your doctor to make sure that the doses or replacement hormones are adequate but not excessive. If you're having persistent problems with your medications, you may need adjustments in the doses or timing of the medications.
If you have untreated Addison's disease, an addisonian crisis may be provoked by physical stress, such as an injury, infection or illness.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.