Addison's disease

Addison's disease is an endocrine disorder where the adrenal gland do not produce an adequate amount of glucocorticoids, mineralocorticoids, and adrenal androgens. It is also called primary adrenal insufficiency.

The adrenal glands, also known as suprarenal glands, are two small triangular-shaped glands located just above the kidneys. They produce and secrete hormones that are essential for the body. The outer part of the gland is known as the cortex and the inner part is known as the medulla.

Addison's disease involves a disrupted functioning of the cortex that cause a decreased production and secretion of two important hormones:

• Cortisol: Regulates the functioning of numerous organs and tissues throughout the body.
  • Is involved in the metabolism of carbohydrates, fats, and proteins
  • Regulates blood pressure
  • Help maintain blood sugar levels
  • Regulates kidney, brain, and nerve function
  • Is important in the response of the immune system
• Aldosterone: Essential to regulate salt and water balance of the body.

Addison's disease has an incidence of approximately 1 per 100,000 of the population per year. It affects both men and women of all ages.

The most common cause is due to an autoimmune disorder (70% of all cases) where the body erroneously produces antibodies against the cells of the adrenal glands, destroying them. It is unclear why this happens.

The second most common cause is due to tuberculosis (20% of cases), a contagious infection.

It may also be caused by:

• Other infections (Histoplasmosis, HIV/AIDS, Cytomegalovirus infection, Cryptococcosis, Waterhouse-Friderichsen syndrome, etc.)
• Hemorrhage
• Hemochromatosis (increased deposition ion of iron in the adrenal glands)
• Amyloidosis
• Sarcoidosis
• Metastatic cancer
• Medications (such as ketoconazole or rifampicin)
• Congenital adrenal hyperplasia

The main symptoms related to Addison's disease are:

• Gastrointestinal symptoms (abdominal pain, nausea, and vomiting)
• Weakness and fatigue
• Anorexia and weight loss
• Hypoglycemia (low blood sugar)
• Postural or orthostatic hypotension (dizziness when standing)
• Dark or pigmented patches on the skin and the mucous membranes
• Muscle and joint pain
• Apathy and changes in emotion and behavior
• Stress intolerance
• Bradycardia (slow heart rhythm)
• Lose of pubic and underarm hair in women and menstrual disorders

Some tests may help to diagnose Addison's disease:

• Plasma cortisol test: A level below 10 μg/dL is usually a sign of the disease.
• Adrenocorticotropic hormone (ACTH) stimulation test: ACTH hormone is administered to stimulate cortisol production. Basal serum cortisol is measured after 30 and 60 minutes of stimulation with 250 μg of Cosyntropin or Cortrosyn. The test is considered normal if basal serum cortisol is greater than 5 μg/dL, with a 30-60 minute increase of 7 μg/dL, and a peak of 15 μg/dL.
• Adrenocorticotropic hormone (ACTH) blood test: The ACTH hormone level will be increased. A levels greater than 250 pg/mL is common in Addison's disease.
• Other tests looking for the underlying cause: They include the anti-adrenal antibody screen, screening for tuberculosis and the assessment of the hypothalamic-pituitary-adrenal axis.

The recommended treatment consists of glucocorticoids (corticosteroids) and mineralocorticoids replacement (oral administration).

• Glucocorticoids: Cortisone, hydrocortisone (synthetic cortisol), prednisone or dexamethasone to restore cortisol level.
• Mineralocorticoids: Fludrocortisone to treat the decreased level of aldosterone.

In any case, when a patient has any kind of trauma, infection, surgery or stress it is recommended to double the dose.

It is necessary to look for medical care in case of food intolerance (e.g. gastritis that reduce the effect of oral administration of the medication) and to wear a medical identification card.

In case of suffering an acute adrenal crisis, it is necessary to inject 100 mg of hydrocortisone solution (Hydrocortisone Sodium Succinate) I.V. (intravenous) every 8 hours.

Without treatment, the life expectancy is less than two years. With drug therapy, patients can expect to enjoy a normal lifespan.