Insufficient levels of corticosteroid hormones in the blood, causing changes in body chemistry
Corticosteroids are adrenal hormones involved in metabolism (the chemical reactions constantly occurring in the body). They also help to control blood pressure and salt and water balance in the body. In the rare disorder Addison’s disease, underproduction of corticosteroids leads to changes in body chemistry. The condition is twice as common in women and sometimes runs in families.
The usual cause of Addison’s disease is damage to an adrenal gland by an autoimmune disorder, in which the body attacks its own tissues. Less common causes of the disorder include HIV infection and AIDS, tuberculosis, growth of cancer cells in the adrenal glands, lack of stimulation from the pituitary gland (see Hypopituitarism), and sudden, severe low blood pressure (see Shock).
Corticosteroid secretion is also suppressed if you take corticosteroid drugs long term for another disorder. If you suddenly stop treatment, undergo surgery, or become ill, levels of natural corticosteroids will be too low.
The symptoms of Addison’s disease appear gradually but become increasingly obvious over a period of several weeks or months. You may develop:
Vague feeling of ill health.
Tiredness and weakness.
Gradual loss of appetite.
Skin pigmentation similar to suntan, especially in the creases of the palms and on knuckles, elbows, and knees.
People with Addison’s disease usually develop low blood pressure (see Hypotension). If you develop a serious illness or sustain an injury, corticosteroid levels may be too low for your body’s needs, and this may result in a condition called an Addisonian crisis. In such a crisis, excessive loss of salt and water results in dehydration, extreme weakness, abdominal pain, vomiting, and confusion. Left untreated, a crisis may lead to coma and death.
The diagnosis will be obvious if you have suddenly stopped taking corticosteroid drugs. Otherwise, if your doctor suspects Addison’s disease, you may have a blood test to measure salt and potassium levels. Further tests may include blood tests to check levels of corticosteroids or to assess your response to an injection of a substance that normally stimulates the adrenal glands.
Any underlying conditions will be treated if possible. In addition, people with Addison’s disease usually need long-term treatment with oral corticosteroid drugs.
The dose of corticosteroid drugs will need to be increased in times of illness or stress. If you develop an infection while taking corticosteroid drugs long term, you should increase the dose as advised and consult your doctor. If you are vomiting or unable to take the drugs orally, you will need an injection of corticosteroids. Corticosteroid injections are also needed as emergency treatment in an Addisonian crisis along with intravenous fluids and glucose. If you are taking corticosteroid drugs long term for any reason, you should carry a card or wear a tag with this information.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.