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

There are two adrenal glands, each has an inner and outer layer that perform 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 adrenal glands is destroyed, which 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 mineralcorticoids. 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, the blood pressure will drop.

When cortisol and aldosterone are not produced in sufficient quantities, they 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, but otherwise, Addison’s disease should not affect your quality of life, or your natural lifespan.

If left untreated, the amount of steroid hormones in the body will gradually fall, and the symptoms of Addison’s disease 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.