Addison’s disease is a rare condition which affects the adrenal glands. It is also identified as primary adrenal insufficiency and hypoadrenalism. Addison’s disease affects the body’s production of two important hormones: cortisol and aldosterone.
The adrenal glands are small glands based higher than the kidneys, with each person possessing two adrenal glands. The hub of the adrenal gland (known as the medulla) produces adrenaline, while the outer sector of the gland (known as the cortex) produces steroid hormones. In people with Addison’s disease the cortex is usually damaged and this prevents the glands from producing aldosterone and cortisol, two types of steroid hormones.
Cortisol and aldosterone have important functions within the body. Cortisol is involved in metabolic processes, regulating blood pressure, regulating energy levels and controlling the body’s reply to traumatic situations. Aldosterone is important for regulating the sum of water and sodium in the blood, which helps to control blood pressure.
How common is Addison’s disease?
Addison’s disease is a rare condition and affects approximately 14 in every 100,000 people in the UK. The disease affects males and females equally and can affect individuals of all ages. There are currently around 8,400 causes of Addison’s disease in the UK, according to information from the Department of Health.
What causes Addison’s disease?
Addison’s disease happens when the outer cortex of the adrenal glands is damaged and the most common cause of the damage is autoimmune conditions. Autoimmune conditions cause the body’s immune system to produce antibodies, which attack healthy cells and organs by mistaking them for a harmful threat. In the UK and other developed countries, autoimmune conditions cause 80 percent of cases of Addison’s disease.
If 90 percent of the outer cortex of the adrenal glands is damaged, this prohibits the glands from producing cortisol and aldosterone. As the levels in the blood decrease this causes symptoms of Addison’s disease to develop.
There is some evidence to suggest that genetics plays a role in increasing the risk of Addison’s disease. Certain genetic variants, which increase the risk of autoimmune conditions, have been identified and there is specific genetic coding that has been found in people with Addison’s disease and other autoimmune diseases, including vitiligo, hypothyroidism (underactive thyroid gland) and type 1 diabetes.
Tuberculosis can also cause Addison’s disease, though it is uncommon in the UK. In the developing world tuberculosis remains a problem and the proportion of cases of Addison’s disease linked to TB is higher than it is in the developed world. Tuberculosis causes Addison’s disease if the disease damages the outer cortex of the adrenal glands.
Other possible causes of Addison’s disease include:
- Cancer (if cancerous cells spread to the adrenal glands from a different part of the body).
- Surgery on the adrenal glands, to remove a tumour for example.
- Haemorrhage in the adrenal glands, sometimes caused by meningitis or sepsis.
Symptoms of Addison’s disease
The early symptoms of Addison’s disease are similar to those associated with other conditions, including anaemia and flu. They include:
- Generally feeling unwell.
- Loss of appetite.
- Muscle weakness.
Dehydration is often experienced by people with Addison’s disease and is caused by reduced levels of aldosterone, which is in charge of controlling sodium and water levels in the blood.
Other symptoms include:
- Lack of energy and motivation.
- Mood swings.
- Feeling thirsty.
- Craving salty foods.
- Weight loss.
- Urinating frequently.
- Low blood sugar (hypoglycaemia).
As the disease progresses the symptoms tend to get worse and they can also become more severe in times of stress. Symptoms of advanced Addison’s disease include:
- Low blood pressure.
- Feeling faint.
- Constantly feeling tired and exhausted.
- Reduced libido (usually in women).
- Joint pain and muscle ache.
- Sickness and diarrhoea.
- Discolouration of the gums, lips and skin (this usually appears as a brownish colour and is known as hyperpigmentation).
- Muscle cramps.
If Addison’s disease is left untreated or poorly managed an individual may experience adrenal crisis, which is caused by the levels of cortisol and aldosterone falling over a period of time. During an adrenal crisis symptoms come on and off quickly and are usually severe. Symptoms of adrenal crisis include:
- Severe dehydration.
- Severe low blood pressure.
- Extreme weakness in the muscles.
- Severe vomiting.
- Severe diarrhoea.
An adrenal crisis can be very serious and should always be treated as a medical emergency. If you know somebody with Addison’s disease or you come across somebody with the disease and notice the symptoms listed above, call 999 immediately and wait with them until help arrives.
How is Addison’s disease diagnosed?
If you experience symptoms or feel unwell you should see your GP. Your GP will ask you questions about your symptoms, medical history and will also want to find out if you have a family history of autoimmune conditions. Your GP will check for signs of hyperpigmentation on your skin and check your blood pressure. If your GP suspects that you have Addison’s disease they will refer you to a specialist for further tests.
Blood samples will be taken and analysed to measure the levels of sodium, potassium and cortisol. If the levels of cortisol or sodium are low and the level of potassium is high, this may indicate Addison’s disease. Other tests may also be ordered by an endocrinologist (a specialist in hormones), which would include tests to check for the following signs of Addison’s disease:
- Low level of aldosterone.
- Low level of glucose.
- High level of ACTH (adrenocorticotropic hormone).
- Presence of adrenal antibodies.
A test called a synacthen stimulation test may also be conducted. This test involves taking blood samples before and after an injection of synacthen, an artificial form of ACTH. If the sample shows that the level of ACTH is high but levels of aldosterone and cortisol are low, this usually confirms that the patient has Addison’s disease.
Thyroid function tests may also be carried out to check that the thyroid function is working properly.
Treatment for Addison’s disease
In cases where Addison’s disease is caused by an underlying health condition, such as tuberculosis or infections, treating the cause often improves symptoms. Treatment for Addison’s disease involves taking hormone replacement medication on a daily basis for life. With the help of this medication most people are able to live a normal, healthy life.
Treatment usually involves corticosteroid replacement therapy which lasts a lifetime. This form of medication is used to replace the cortisol and aldosterone that the body is unable to produce. Hydrocortisone is used most commonly to replace cortisol, while fludrocortisone is used to replace aldosterone. Your GP may also advise you to start including more salt in your diet.
Living with Addison’s disease
If you stick to your medication and see your doctors on a regular basis, there is no reason why you should not be able to live a healthy, fulfilling life. However, if Addison’s disease is poorly managed this can be serious and potentially fatal and it is therefore vital to take the following precautions:
- Always ensure you renew your prescriptions.
- Keep spare medication.
- If you are travelling or plan to be away from home make sure you have plenty of medication with you.
- Take your medication at the recommended time each day.
- Keep your medication on you at all times.
It is also advisable to tell friends, relatives and colleagues about your condition, and inform them where you keep your medication in case you suffer an adrenal crisis. It is also a good idea to wear a bracelet that alerts people to your condition, which will be helpful in the event of an accident, for example, as your body is supposed to produce cortisol to cope with the shock. Therefore, if you are involved in an accident or an emergency situation, the paramedics will see your bracelet and know that you need an injection of hydrocortisone. Bracelets are available from a variety of outlets and you can ask your GP for further information. They will contain information about your condition and an emergency contact number.
You will be trained in how to inject yourself with hydrocortisone in the incident of an emergency, but it is also beneficial for a family member to learn how to do this in case you suffer a crisis.