Addison's Disease - What is Addison's Disease?

By Dr Ananya Mandal, MD

Addison’s disease is a rare condition that affects the adrenal glands. This condition affects 1 to 4 persons in every 100,000 in United Kingdom and around 4 to 6 persons per 100,000 in the United States of America.

The average age of diagnosis is around 40 years. Although both men and women may be affected, there a slight predominance of occurrence among females.

Addison’s disease or primary adrenal insufficiency was first described by Dr. Thomas Addison, an English physician in1855 and has been thus named after him.

What are the adrenal glands?

The adrenal glands are small cap or pyramid like organs that lie on top of the kidneys. The adrenals mainly produce two hormones that are important for functioning of the body. These are cortisol and aldosterone. These hormones help to regulate blood pressure.

The adrenal has two zones – the inner medulla that produces the hormone adrenaline and the outer cortex that produces steroid hormones like cortisol and aldosterone.

What happens in Addison’s disease?

In Addison’s disease, the cortex of the adrenal glands is destroyed. This drastically reduces its capability to produce the two steroid hormones - cortisol and aldosterone.

Cortisol is also called the stress hormone. It is secreted when the body is under stress and maintains normal blood sugar levels by regulating metabolic pathways. Aldosterone maintains the balance of salt and water and helps control blood pressure.

What causes Addison’s disease?

Addison’s disease is found to be an autoimmune disorder. This means that the body’s own immune system fails to recognize the cortex cells within the adrenal glands as self and begins to attack and destroy them.

Other diseases like tuberculosis, cancer, HIV infection that affect the adrenal cortex may also cause Addison’s disease.

Symptoms of Addison’s disease

Symptoms may begin with tiredness, dehydration, dizziness and cramps.

Over time there may be fainting spells, exhaustion and dark pigmentation over skin.

When the person faces a stressful situation like an accident or illness, the symptoms often worsen.

Diagnosis of Addison’s disease

Diagnosis is made commonly by using the ACTH stimulation test which measures levels of cortisol in the blood and urine after giving a dose of a synthetic stimulating hormone ACTH.

In normal persons ACTH administration results in secretion of cortisol while in those with Addison’s disease there is little or no response.

Treatment of Addison’s disease

Addison’s disease is treated with medications that serve to replace the hormones that the body cannot produce. These drugs, including corticosteroids, would replace the natural cortisol produced by the body and with regular medication the symptoms may be well controlled.
The symptoms may reappear when there is a stressful situation however. With replacement therapy persons with Addison’s disease may lead a normal life. However, it left untreated levels of cortisol may reach dangerously low levels leading to severe fall in blood sugar and other complications. This is called adrenal crisis and is a medical emergency.

Reviewed by April Cashin-Garbutt, BA Hons (Cantab)

Sources

  1. http://www.nhs.uk/conditions/Addisons-disease/Pages/Introduction.aspx
  2. http://www.bbc.co.uk/health/physical_health/conditions/addisons1.shtml
  3. http://www.addisons.org.au/assoc/whatis.pdf
  4. http://endocrine.niddk.nih.gov/pubs/addison/addisons.pdf
  5. http://www.med.unc.edu/medicine/web/addisons.pdf
  6. http://www.uspharmacist.com/CMSDocuments/2010/6/PTA1006%20Addison%20all.pdf

Further Reading

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