Addison's disease

Addison’s disease (also known as primary adrenal insufficiency or hypoadrenalism) is a rare disorder of the adrenal glands. It affects the production of two hormones - cortisol and aldosterone - which help to regulate blood pressure.

Adrenal glands

The adrenal glands are two small, triangular-shaped glands that sit on top of the kidneys, high up inside the back of the abdominal wall.

Each gland has an inner and outer layer that have separate functions:

• the inner area (the medulla) produces the hormone adrenaline, and
• the outer layer (the cortex) produces steroid hormones and small amounts of the male and female sex hormones, testosterone and oestrogen.

In Addison’s disease, usually the cortex of the both adrenal glands is destroyed. This disrupts the production of steroid hormones, cortisol and aldosterone.

Cortisol

Cortisol belongs to a group of hormones called glucocorticoids. It is often called the stress hormone because it is released in stressful situations. Cortisol helps you to cope by invoking the fight or flight feelings. It also has several other functions, including:

• maintaining blood pressure and heart function,
• suppressing the immune system,
• maintaining your blood glucose (sugar) levels, and 
• regulating your metabolism (the process that turns food into energy).

Aldosterone

Aldosterone is part of a group of hormones called mineralocorticoids. It maintains the balance of salt and water in the body by helping the kidneys keep hold of the sodium in the blood, while removing the potassium. If the kidneys cannot do this properly, the volume of blood falls. If there is less blood being pumped around the body, blood pressure will drop.

When cortisol and aldosterone are not produced in sufficient amounts, it can cause the symptoms of Addison’s disease.

How common is Addison’s disease?

Addison’s disease is rare. It affects about four people in every 100,000 in the UK. The condition can be diagnosed at almost any age and affects both men and women equally.

Outlook

Once diagnosed, it is possible to treat Addison’s disease using medication to replace the missing hormones. The medication will be required for the rest of your life. Your medication may need to be adjusted during particularly stressful periods, such as pregnancy or illness. Otherwise, Addison’s disease should not affect your quality of life or your natural lifespan.

If Addison's disease is left untreated, the amount of steroid hormones in the body will gradually fall, and the symptoms will get progressively worse. Eventually, this will cause an adrenal crisis (when the symptoms are severe and the blood pressure drops very low). This can be fatal if it is not treated immediately.