Health Conditions Autoimmune Diseases

Addison's Disease - Definition, Causes, Symptoms, Diagnosis and Treatment

Addison's disease affects people from all age groups, as well as both men and women. Addison's disease is often characterized by muscle weakness, fatigue, weight loss, low blood pressure, and on occasion by a darkening of the person's skin.

Defining Addison's Disease

Addison's disease is caused by either a partial or complete failure of the outer layer of a person's adrenal glands, which produce hormones that control a number of bodily functions. The disease involves a chronic deficiency of cortisol, aldosterone, and adrenal androgens. When a person's body is deficient in these hormones they may experience low levels of salt and high levels of potassium which cause an electrolyte imbalance in their body.

Addison's disease affects people from all age groups, as well as both men and women. Addison's disease is often characterized by muscle weakness, fatigue, weight loss, low blood pressure, and on occasion by a darkening of the person's skin. Addison's disease happens when a person's adrenal glands do not produce enough cortisol, or in some cases enough aldosterone. The disease is sometimes referred to as, 'Chronic Adrenal Insufficiency.' Cortisol is a hormone that affects nearly every organ and tissue in a person's body.

The most important job cortisol has is to help a person respond to stress; it also assists in maintaining cardiovascular function, blood pressure, and in slowing a person's immune system's inflammatory response. Cortisol balances the effects of insulin in breaking down sugars for energy, regulation of metabolism of proteins, carbohydrates, and fats. The hypothalamus and pituitary gland regulate cortisol. In fact; one of the main functions of the pituitary gland is to secrete Adrenocorticotropin (ACTH) – a hormone which stimulates a person's adrenal glands.

A person's adrenal glands are located right above their kidneys, producing the cortisol and other hormones called, 'Corticosteroids,' that they need. Some of these corticosteroid hormones are essential for life. Addison's disease commonly occurs in persons between the ages of thirty and fifty years, although it can affect people of any age or sex.

Causes of Addison's Disease

There are some different reasons a person may not produce enough cortisol. 'Primary Adrenal Insufficiency,' occurs when there is a disorder of a person's adrenal glands. 'Secondary Adrenal Insufficiency,' occurs when the person's pituitary gland is not secreting enough ACTH. The most common form of Addison's disease in America involves autoimmune destruction of the adrenal glands that can happen either alone, or as a part of a syndrome. Additional causes of Addison's disease may include tuberculosis, adrenal hemorrhage, or genetic disorders. People who have been receiving a form of glucocorticoid hormone such as Predinsone to treat another disorder who suddenly stop taking it may experience a temporary type of secondary adrenal insufficiency.

Symptoms of Addison's Disease

Addison's disease presents a number of different symptoms which often begin slowly. Characteristic symptoms of the disease include fatigue and muscle weakness, weight loss, and loss of appetite. Half of all person's with Addison's disease experience diarrhea, nausea and vomiting. People with the disease often experience low blood pressure that falls even lower when they stand, causing them to feel dizzy or possibly even faint. Skin changes are common as well in person's with Addison's disease; they many times experience areas of dark tanning which cover their skin that is most visible in skin folds, scars and pressure points.

Persons with Addison's disease may experience depression and irritability. Cravings for salty foods is common due to a loss of salt from their system. Children with the disease are affected by low blood sugar levels more often than adults. Women with Addison's disease can experience menstrual periods that can be either irregular, or cease completely.

The symptoms of Addison's disease, for approximately twenty-five percent of persons affected, do not appear until they experience an, 'Addison's Crisis.' The symptoms of Addison's disease tend to progress slowly, causing people to ignore them until either a stressful event, illness, or an accident makes the symptoms worse. An Addison's crisis requires prompt medical attention; such a crisis can be fatal. The symptoms of an Addison's crisis include:

* Dehydration
* Low blood pressure
* Loss of consciousness
* Severe vomiting and diarrhea
* Sudden penetrating pain in the lower back, abdomen, or legs

Diagnosing Addison's Disease

When Addison's disease is in its early stages it can be difficult to diagnose. Doctors diagnose the disease through a review of the person's medical history, the symptoms the person presents, a physical examination, as well as blood testing. The aim of the laboratory tests is to determine not only the levels of cortisol in the person's system and whether or not they are sufficient, but also to establish a cause. A doctor may order X-rays of the person as well. There are a couple of different laboratory tests a doctor may order in relation to Addison's disease.

ACTH Stimulation Test: The ACTH Stimulation Test is one that measures cortisol in the person's blood and urine before they are given an injection of a synthetic form of ACTH. In the, 'rapid,' ACTH test, the cortisol level in the person's blood is measured thirty to sixty minutes after they have received the injection of ACTH. The expected response is that the person's ACTH levels in both their blood an urine will rise. Persons who experience a form of adrenal insufficiency respond either poorly, or not at all.

CHR Stimulation Test: The CHR Stimulation Test is required when a person has responded poorly to the ACTH Stimulation Test. The CHR Stimulation Test assists in determining the cause of the person's adrenal insufficiency. During the test the person is given an intravenous injection of synthetic CRH and their blood cortisol is measured not only before; but thirty, sixty, ninety, and one-hundred and twenty minutes after they have received the injection. Persons with primary adrenal insufficiency have high ACTH's, yet do not produce cortisol. Person's with secondary adrenal insufficiency have deficient cortisol responses, but either absent or delayed ACTH responses. An absent ACTH response suggests that the person's pituitary is the cause. A delayed ACTH response suggests their hypothalamus is the cause.

People who have received a diagnosis of primary adrenal insufficiency may find a doctor ordering X-rays to discover if their adrenal glands present any signs of calcium deposits, which could indicate tuberculosis. The doctor could order a TB skin test as well. People who have been diagnosed with secondary adrenal insufficiency might find their doctor ordering a CT scan to determine further methods of treatment, as well as additional methods of testing their pituitary gland and hormone testing.

Treatment of Addison's Disease

The treatment of Addison's disease involves using a combination of glucocorticoids and mineralocorticoids to replace the ones the person's body is not producing. Cortisol is replaced with Hydrocortisone tablets that can be taken once or twice each day. If the person is also experiencing an aldosterone deficiency, they can take a mineralocorticoid called, 'Fludrocorisone,' once each day. Persons taking Fludrocorisone are many times advised by their doctor to increase the amount of salt they take in. Persons affected by secondary adrenal insufficiency usually continue to produce the amount of aldosterone they need. The amount of these medications are adjusted in order to meet the requirements of individuals.

People who are experiencing an Addison's crisis accompanied by low blood sugar, low blood pressure, and high levels of potassium are at great risk of life. Doctors commonly treat an Addison's crisis with injections of hydrocortisone, saline, and dextrose, producing quick improvement in the person involved. Once the person can drink fluids and take oral medications, the amount of hydrocortisone they take is decreased until they reach a maintenance dose. If they require fludrocortisone, this medication level is achieved as well.

Doctors are not able to make a reliable diagnosis of Addison's disease while a person is being treated for an Addison's crisis. A doctor can; however, measure the person's blood ACTH and cortisol both during the crisis and prior to administration of any glucocorticoids. These measurements are usually enough to make a diagnosis. Once the crisis is over and medication related to it have ceased, a doctor commonly waits for up to a month in order to make an accurate diagnosis.

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