Addison’s disease is a condition which involves a lot of complex, medical terms. It can be confusing to know what these terms mean so we have produced a short glossary explaining some of the more common medical expressions you may come across.

Adrenal crisis
An adrenal crisis occurs in people with Addison’s when the cortisol present in their body is not sufficient to keep it functioning. Common triggers include vomiting, diarrhoea, other infections such as flu or extreme emotional stress. An adrenal crisis is a life-threatening situation and requires immediate medical treatment. The person needs to be given an emergency injection of hydrocortisone straight away. You can read more about this in the emergency section of our website or visit our ADSHG video hub.


Adrenal glands
The adrenal glands are small, triangular shaped glands, one sits on top of each kidney. They produce a number of hormones, including cortisol and aldosterone, which keep the body functioning correctly.


Adrenal cortex
This is the outer layer of the adrenal gland. It produces the corticosteroid hormones, cortisol and aldosterone, which are essential for life. They help to control blood sugar, blood pressure, salt and water balances in the body.


Adrenal medulla
The inner core of the adrenal glands, it produces adrenaline, sometimes referred to as the ‘fight or flight’ hormone.


This is one of the hormones produced by the adrenal glands. It stimulates the heart to beat faster and raises blood pressure. It is sometimes known as the ’fight or flight’ hormone because the body produces it in large amounts in response to scary situations. It is produced in the inner core of the adrenal gland, known as the medulla. Sometimes adrenaline is also called epinephrine. Adrenaline is not essential for life; it can be compensated for by a similar hormone noradrenaline, which is produced in nerve endings around the body.


This is one of two adrenal hormones that is essential for life. It helps to control blood pressure, sodium and potassium levels and the amount of fluid in body tissues. Known as a corticosteroid, it is produced in the outer layer of the adrenal gland, the cortex, along with cortisol.


This is a form of iron deficiency where the body gradually loses the ability to absorb enough iron from the food that is eaten. In Addison’s, this is often caused by damage to the stomach lining (atrophic gastritis), so that it loses the ability to secrete certain enzymes necessary for the absorption of iron and vitamin B12. This makes the person feel weak, tired and breathless. It is treated with iron supplements.


This is the collective name for the adrenal hormones, which are essential for life. They are produced by the outer layer of the adrenal gland, known as the cortex. There are two main corticosteroids: cortisol and aldosterone.


This is one of two adrenal hormones that is essential for life. It is sometimes called a glucocorticoid hormone, because it helps to control blood sugar levels as well as blood pressure, salt and other minerals in the bloodstream. Like aldosterone, it is produced in the outer layer of the adrenal gland, the cortex. People with Addison’s can not produce cortisol and they need to take medication to replace this hormone.


This was the name given to the first man-made chemical version of the adrenal corticosteroid hormones produced by the body. This is short for its full chemical name of cortisone acetate. Cortisone is now understood to be a weaker (inactive) form of the more important adrenal hormone, cortisol. To become active in the bloodstream, it must first be converted by the liver into cortisol, so it is not as fast acting as other medications such as hydrocortisone.


Dehydroepiandrosterone (DHEA)
DHEA is another hormone that is produced by the outer layer of the adrenal gland, the cortex. It influences stamina and libido and is a precursor hormone (meaning the body can convert it into lots of other types of hormone).

DHEA is optional, not all people find it helpful; usually 25–50mg per day taken in one dose on wakening. DHEA can’t be prescribed on the NHS as it is classed as a food supplement. Some ADSHG members receive DHEA on a Named Patient Basis following discussions with their Doctors, where others purchase DHEA direct from a pharmacy or health food store. For more discussion on this, join the conversation on our online forum. You can also read more about DHEA under "Replacement of other adrenal hormones" in the 'Living with Addison's' Book.

Several clinical trials replacing DHEA have been performed demonstrating the benefits of DHEA replacement therapy for many women with primary and adrenal insufficiency.


This is a condition that occurs when another endocrine gland, the pancreas, stops working properly. It happens when the pancreas can’t produce enough of another essential hormone, insulin, so that the person’s blood sugar climbs too high, particularly when they eat something. Depending on the type of diabetes they are diagnosed with, people with this condition usually need to inject themselves with insulin to keep their blood sugar levels in balance. Diabetes is 300 times more common than Addison’s. Some people with Addison’s also get diabetes.


This is a doctor who specialises in treating patients with hormone-related conditions. If your GP suspects you have Addison’s, you will be referred to see an endocrinologist who will use their specialist knowledge to provide the correct diagnosis and oversee ongoing treatment.


This is the study of hormones and the body’s glands that produce hormones (the endocrine glands). It is a specialised branch of medicine. The main endocrine glands are the pituitary, hypothalamus, thyroid, parathyroid, pancreas, ovaries or testes and adrenals.


This is a synthetic chemical compound that is the key component in the medication taken to replace the adrenal hormone aldosterone. It is not quite identical to aldosterone, but has the advantage that it is longer-acting. Most people with Addison’s take it once or twice a day: on waking, with a second, smaller dose sometimes taken at lunchtime or bed-time. Read our blog article "Why Salt?" to learn more about the connection between aldosterone, fludrocortisone and salt cravings. 


This is a type of protein found in wheat, barley and other grains. Some people become allergic to gluten and can’t eat foods such as bread, pasta, or cakes made with wheat flour without becoming ill. People with Addison’s are more likely to react badly to gluten. This allergy is known as coeliac disease.


These are special molecules that various glands in the body produce. They are pumped into the bloodstream where they act as chemical messengers, helping to keep various body systems well-balanced. Hormones control lots of functions within the body including growth, metabolism, appetite, blood pressure, reproduction and many other important functions.


This is now the main glucocorticoid medication for people with Addison’s. It was first developed in the 1960s and chemically it is identical to the adrenal hormone cortisol. It is fast acting and is usually absorbed from the stomach within 30 minutes of being swallowed. This means it has to be taken two or three times a day: the first dose as soon as the person wakes up; the next, smaller dose five or six hours later.


Hydrocortisone Day Curve
Hydrocortisone is measurable in blood (as cortisol) and this can help guide your dosing. Dosage is dependent on bodyweight, metabolism and absorption; so dosage is best confirmed by clinical assessment as well as, in some cases, a ‘day curve’.

A hydrocortisone ‘day curve’ can be performed in an endocrine ward, where you take your normal daily steroid replacement and you have blood taken 4 or 5 times during the day to measure the amount of cortisol absorbed into the blood. If the levels are too low, your doctors would use this to guide a dose increase.


If conventional treatment on hydrocortisone does not improve symptoms, alternative oral steroids can be used to see if these help. For example low dose prednisolone, dual release hydrocortisone (Plenadren, Duocort) and delayed release hydrocortisone (Chronocort).

A single or twice-daily dose of prednisolone for some improves their symptoms. You can read more about Professor Karim Meeran’s research into prednisolone on the Imperial, London, website here, to learn more and see if it would be helpful for yourself.


Pituitary gland
This is a small pea sized endocrine gland found at the base of the brain, inside the skull. It is sometimes known as the master gland because it pumps out lots of different hormones that control the function of many other endocrine glands around the body, including the production of cortisol in the adrenals and thyroid hormones in the thyroid. If the pituitary gland stops functioning correctly, it stops sending these hormone signals to the adrenal glands, meaning they don’t work – this is called secondary adrenal insufficiency.


Short Synacthen test
This test is also called the ACTH stimulation test or a cosyntropin test. It measures the ability of your adrenal glands to produce cortisol and involves two blood samples being taken. The first is a ‘baseline’ reading to measure how much cortisol is in your blood when at rest. You are then given an injection of a hormone called ACTH (this is the hormone normally produced by your pituitary gland to instruct your adrenal glands what to do) and a second blood sample is taken 30-60 minutes after this. If the adrenal glands are healthy, cortisol production in the second sample will exceed a certain level, commonly 500-550 nmol/L. By contrast, adrenal glands that aren’t working properly will not be able to produce this amount of cortisol.


A bacterial infection that usually attacks the lungs; it can also infect other parts of the body. When it damages the lungs it causes a persistent cough, fever, night sweats and weight loss. Treatment is difficult and requires long courses of antibiotics. Left untreated, tuberculosis can result in death.


Thyroid gland
This is another endocrine gland that produces hormones which are essential for life. Thyroid hormones control body temperature and energy. People with Addison’s are more likely to lose thyroid function and many need thyroid supplements as well as replacement adrenal medications.


Vitamin B12 deficiency
Sometimes known as pernicious anaemia, this is a condition that occurs when damage to the stomach lining (atrophic gastritis) means the body cannot absorb enough vitamin B12. It usually occurs alongside iron deficiency, making the person feel weak and tired, sometimes with tingling or numbness in the hands and feet. It is treated with vitamin B12 injections or supplements.


This is a harmless skin condition where patches of skin gradually lose their pigmentation so that they appear white and get easily sunburnt. It is more noticeable in dark-skinned individuals. Some people with Addison’s also get vitiligo.


Further resources:

You can find explanations for further medical terms on an educational website maintained by the Society for Endocrinology, You and your hormones.