Abnormal

Varying from what is regular or usual.

Absorption

The taking up of fluids or other substances by the tissues.

Acidosis

A condition in which the relation of alkalinity to acidity of the blood is disturbed, with an increase in the hydrogen ion concentration. It is characterised by vomiting, drowsiness, hyperventilation (overbreathing), acetone odour of breath (or "new-mown hay") and acetone bodies in the urine. It may occur in diabetes mellitus owing to incomplete metabolism of fat. Also known as Ketoacidosis or Ketosis.

Acromegaly

A chronic condition producing gradual enlargement of the hands, feet, the long bones, and the bones of the head and chest. Associated with over-activity of the anterior lobe of the pituitary gland. It can result in excessive height growth.

ACTH

Adrenocorticotrophic hormone. (ACTH) This is the messenger hormone produced by the pituitary gland which regulates adrenal production of cortisol

ACTH Stimulation Test

This is a blood test in which the amount of cortisol in the blood is measured before and after an injection of ACTH, normally over a period of 60 minutes. People with adrenal disease produce a comparatively small amount of extra cortisol in response to the injection. Different hospitals apply different thresholds to define how small an increase in blood cortisol means adrenal failure but typically an increase of <200nmol/L within 30 minutes is regarded as a failure.

Addisonian Crisis

This is a potentially life threatening situation and requires urgent and immediate medical treatment. Symptoms include a serious drop in blood pressure, mental confusion, and weakness. The signs of steroid insufficiency normally precede these and can include headache, nausea, vomiting, dizziness, abdominal pain and diarrhoea.

Adenoma

A non-malignant tumour of glandular tissue.

Adrenalectomy

Surgical removal of the adrenal glands. Replacement therapy of cortisone is essential.

Adrenal Glands

The two small glands, which are about the size of a walnut and are positioned just above the kidneys, at the top of the abdomen, near the back. The adrenal glands are really two endocrine (ductless or hormone producing) glands in one. The inner or middle of each gland (called the medulla) produces the hormone "epinephrine" (commonly known as "adrenaline"). However, the adrenal medulla is not essential for survival as its absence does not cause disease and the rest of the nervous system can adequately compensate for the lack of adrenaline.

Adrenaline

Also known as Epinephrine, this is the hormone which is produced at times of stress and helps the body respond to "fight or flight" situations by raising the pulse rate, adjusting blood flow and raising blood sugar.

Adrenoleukodystrophy

This is a rare, hereditary condition, which includes neurological degeneration and adrenal insufficiency. It is triggered by the abnormal metabolism of fatty-acids.

Aldosterone

This is one of the hormones produced by the adrenal medulla. It helps maintain blood pressure and blood volume and water and salt balance in the body by helping the kidneys retain sodium and excrete potassium. When aldosterone production falls too low, the kidneys are not able to regulate salt and water balance, causing blood volume and blood pressure to drop.

Androgens

These hormones are produced in small quantities and are present in both sexes. In the female, this is essentially the only source for such hormones and these have a role in sexual libido and also in the distribution of the female body hair. In females, oestrogens are also produced by the adrenal cortex. In the pre-menopausal state, adrenal oestrogens account for only 4% of the oestrogen supply, but in post-menopausal women, the adrenal cortex is the major source of oestrogens. Oestrogens may also play a part in the distribution of female body hair since they can be converted to steroids with androgen activity in hair follicles.

Autoimmune adrenalitis

This is the most common cause of Addison's Disease in modern times and occurs when an over-active immune system attacks the adrenal tissues. Its cause is unknown but may be viral in origin in some cases.

Autoimmune conditions

This is a general term used to describe the many medical conditions which are caused by an over-active immune system. Some more common autoimmune conditions are rheumatoid arthritis, Hashimoto's thyroiditis, Diabetes mellitus, and hayfever.

Blood sugar

This is used by the body for energy and is an important component. Cortisol helps maintain blood sugar at a stable level. Blood sugar is usually measured as serum glucose, or plasma glucose.

Chronic

This is the medical term to describe a long lasting disease or illness, possibly of slower onset (as opposed to 'Acute', which often refers to one of speedy onset.) It does not usually imply anything about the severity of the disease or illness.

Coeliac Disease

This is sensitivity to gluten, which is found in wheat, barley, oats and rye. It causes the small intestine to become diseased and failing to absorb nutrients properly. A marked improvement can normally be achieved by omitting all foods containing gluten.

Compression Fracture

This is a fracture where the bone "crumbles" and is most commonly seen in osteoporosis.

Congenital adrenal hyperplasia

Cortisol and aldosterone production are blocked by a recessive genetic defect that is caused by this rare hereditary condition. It can also cause over production of androgens (male hormones), which can cause signs of virilisation.

Corticosteroids

This is a generalised term for the cortisol hormone, which the adrenal glands produce. It is also used to describe the synthetic, replacement hormones, such as Hydrocortisone, Prednisolone, Dexamethasone, etc.

Cortisol

This is a type of steroid essential for the general running of the body's metabolism, especially at times of stress or during illness. It mobilises nutrients, modifies the body's response to inflammation, stimulates the liver to raise the blood sugar and also helps to control the amount of water in the body.

Cortisone Acetate

One of the synthetic preparations used in the treatment of Addison's Disease to replace the missing cortisol. Cortisone acetate is an older version of the now more popular Hydrocortisone. It is less readily absorbed by the body and is slower acting because the liver must first convert it into a form the body can use.

Craniopharyngiomas ‡

Craniopharyngiomas are rather uncommon benign tumours, which account for between 4% and 9% of brain tumours in children and 1% in adults. They are congenital, which means they are present from birth, but are not passed on to future generations. They are usually situated close to the pituitary gland and the hypothalamus and consist of solid parts, which often contain calcium, and cysts, which are filled with a dense, oily fluid. Craniopharyngiomas can cause symptoms are any age, from the newborn period to old age, depending on the tumour's rate of growth, but in about 50% of cases, the first effects are noticed during childhood, most commonly between the ages of 5 and 12.

Cushing's Syndrome

A serious condition where there is an over secretion by the adrenal cortex due to an adenoma of either the pituitary or adrenal glands. Symptoms include osteoporosis, weight gain, insomnia, mood swings, depression, fluid retention, "moon" face and thinning skin.

Day Curve Analysis

The most comprehensive test for measuring medication accuracy. This needs to be carried out as an in-patient of the Endocrinology Department of your hospital. This test starts early in the morning, before you take your first dose of medication and involves having blood tests taken every hour, on the hour for 24 hours to monitor the levels of cortisol in the blood. The blood results throughout the day can then be compared to the "ideal" for that of healthy adrenal glands. It is the most accurate way of establishing if you are on the correct dose of Hydrocortisone and allows dose and timings to be adjusted accordingly.

Depression

A mental state of pessimism or despair. Normally, sleep, appetite and concentration are disturbed. A medically defined state of depression is often associated with high cortisol levels, particularly at night.

Dexamethasone

Another of the synthetic preparations used in the treatment of Addison's Disease. This drug is approximately 30 times more potent than Hydrocortisone & is a longer acting drug than Hydrocortisone, staying in the system for a longer period of time. Therefore, doses of Dexamethasone are required to be 50 - 80 times lower than those of Hydrocortisone. Over medication can very easily occur with this medication.

DHEA (Dehydroxyepiandosterone)

A sex hormone, and the third major hormone produced by the adrenal glands. Present in both males and females, DHEA is converted by the body into androgens and oestrogens. It is believed that DHEA improves energy levels, gives protection against osteoporosis, improves libido, gives relief from dry skin and encourages lean muscle.

Diabetes

A disease characterised by excessive excretion of urine and excessive thirst. There are several types of diabetes, most commonly, diabetes mellitus, a deficiency or inefficiency of the pancreas to secrete insulin (often autoimmune in origin). Blood sugar and insulin levels are affected.

Diabetes insipidus

Diabetes marked by an increased flow of urine of low specific gravity, accompanied by great thirst. This disease, which is due to posterior pituitary dysfunction, is rare and some cases can be controlled by daily injections of pituitary extract.

Electrolytes

The maintenance of the correct balance between the different elements in the body tissues and fluids. These include sodium and potassium.

Empty Sella syndrome ‡

A radiological finding where spinal fluid is found within the space created for the pituitary.

Endocrine

Describing those glands whose secretions (hormones) flow directly into the blood and not outwards through a duct. The chief endocrine glands are the thyroid, parathyroids, suprarenals and pituitary. The pancreas, stomach, liver, ovaries and the testicles also produce internal secretions.

Endocrinologist

A professionally qualified physician experienced in the science of the endocrine glands and their secretions.

Fludrocortisone

The only synthetic preparation available to replace aldosterone, one of the adrenal hormones.

Haemochromatosis ‡

A disease caused by excess iron overload in the body.

Histiocytosis ‡

A generic name for a group of syndromes characterized by an abnormal increase in the number of certain immune cells called histiocytes.

Hydrocortisone

Another synthetic preparations used in the treatment of Addison's Disease. Hydrocortisone is now the preferred drug of use as the body quickly and easily absorbs it.

Hyperglycaemia

Excess of sugar in the blood (normal 2.5 - 4.7 mmol/litre when fasting). A sign of diabetes mellitus.

Hyperkalaemia

An excess of potassium in the blood. If untreated, this will lead to cardiac arrest.

Hypernatraemia

An excess of sodium in the blood.

Hyperparathyroidism

Excessive activity of the parathyroid glands, causing drainage of calcium from the bones, with consequent fragility and liability to spontaneous fracture.

Hyperpituitarism

Over-activity of the pituitary gland.

Hypertension

Abnormally high blood pressure.

Hyperthyroidism

Excessive activity of the thyroid gland. This affects the metabolic process, which is speeded up. The appetite is large but weight is lost. The temperature tends to be above normal and respirations are increased. It also affects the nervous system causing the individual to become excitable and restless. Diarrhoea and excessive sweating are also common, along with a rapid pulse and atrial fibrillation (palpitation like symptoms).

Hypoglycaemia

A condition in which the blood sugar level is less than normal. Usually arising in a diabetic patient having insulin, due to too high a dose, delay in eating, or a rapid combustion of carbohydrate. Symptoms include muscle weakness, sweating, mental confusion and poor coordination.

Hypoglycaemic coma

Caused by extremely low blood sugar. The individual loses consciousness following symptoms of extreme weakness, dizziness and mental confusion.

Hypokalaemia

A low potassium level in the blood. This is likely to be present in dehydration and with the repeated use of some diuretics.

Hyponatraemia

A deficiency of sodium in the blood.

Hypoparathyroidism

A lack of parathyroid secretion leading to a low blood calcium and tetany (an increased excitability of the nerves due to a lack of calcium, accompanied by painful muscle spasm of the hands and feet.)

Hypophysis ‡

Another term for the pituitary gland.

Hypopituitarism

Deficiency of secretion from the anterior lobe of the pituitary gland, causing excessive deposit of fat in children. Dwarfism may result. In adults, loss of strength, debility, drowsiness and adiposity (obesity) may occur, together with an impairment of sexual activity and premature senility.

Hypotension

Abnormally low arterial blood pressure. Can cause giddiness and sometimes even a faint, normally on standing (postural hypotension).

Hypothyroidism

An insufficiency of thyroid secretion. In children, it may produce cretinism (characterised by a thickness of the neck, stunted growth, course facial features and impaired mental development). In adults, it leads to myxoedema (swelling of the face, limbs and hands, dry, rough, itchy skin, loss of hair, slow pulse, low body temperature, slowed metabolism and mental dullness).

Idiopathic

Applied to a condition the cause of which is unknown.

Insulin

The endocrine secretion of the pancreas, which regulates sugar metabolism and ensures complete fat combustion. A deficiency of insulin causes Diabetes mellitus.

Kallman syndrome ‡

Describes the occurrence of hypothalamic gonadotrophin releasing hormone deficiency. (see hypergonadism)

Ketones

Produced when the body metabolises fat. Raised levels occur when there is an imbalance in the metabolism and can be associated with several conditions that may damage overall health (e.g.diabetic coma).

Lymphocytic hypophysitis ‡

A rare disorder found in women. It relates to postpartum hypopituitarism and can emulate pituitary adenomas. (See above for postpartum hypopituitarism and pituitary adenomas)

Metabolism

The use of foods by the body following digestion, absorption and circulation to the body cells. Ingested foods are used both as an energy source and, after being broken down chemically during digestion, as basic materials for making complex chemical compounds required by the body.

Mineralocorticosteroids

The general term for the salt and water-regulating hormone, aldosterone, which is produced by healthy adrenal glands.

Normal values

Used to describe the optimum level of hormones and other chemical components of the blood. Most components have an upper and lower limit to the optimum.

Osteomalacia

A disease characterised by painful softening of the bones. It is due to vitamin D deficiency (Ricketts).

Osteopenia

A term used to describe a general deficiency of bony tissue.

Osteoporosis

Rarefaction (loss of density) of bone. Caused a lack in mineral salts in bony tissue. The bones become brittle and liable to fracture. A bone scan is used (often of the pelvis and hip joint) to detect osteoporosis.

Pernicious anaemia

Due to the lack of absorption of vitamin B12 for the formation of red blood cells. It can be caused by Coeliac disease, or an autoimmune deficiency of 'Intrinsic factor', normally secreted by the stomach's parietal cells and which transports B12 through the gut wall into the blood circulation. Treatment is by monthly injection of vitamin B12.

Pituitary Adenomas ‡

A slow growing benign tumour of the pituitary gland.

Pituitary gland

One of the most important endocrine glands, the pituitary is situated at the base of the brain, just behind the eyes. The pituitary regulates and controls the activity of other endocrine glands and many body processes.

Plasma

The yellow fluid part of blood which has been chemically stopped from clotting & thus still contains the clotting factors. (As opposed to 'Serum' which is the yellow fluid part of blood which has been allowed to clot & thus has virtually no clotting factors remaining. Many biochemical blood tests may use either plasma or serum)

Plasma cortisol

The term used to describe the levels of the adrenal hormone, cortisol, in the blood.

Plasma renin

The term used to describe the levels of renin in the blood.

Polyendocrine deficiency syndrome or Polyglandular autoimmune syndrome

The polyendocrine deficiency syndrome is classified into two separate forms, referred to as type I and type II. Type I occurs in children, and adrenal insufficiency may be accompanied by underactive parathyroid glands, slow sexual development, pernicious anaemia, chronic candida infections, chronic active hepatitis, and, in very rare cases, hair loss. Type II, often called Schmidt's Syndrome, usually presents in young adults. Features of type II may include an underactive thyroid gland, slow sexual development and diabetes mellitus. About 10% of patients with type II have vitiligo, or loss of pigment, on areas of skin. Polyendocrine deficiency syndrome could be inherited as frequently more than one family member has one or more endocrine deficiency.

Potassium

An essential mineral in the blood which helps to maintain normal functioning muscles and nerves.

Prednisolone

Another synthetic corticosteroid used in the treatment of Addison's Disease. It is roughly four times stronger than Hydrocortisone and is active in the bloodstream over a longer period of time.

Primary adrenal insufficiency

Results from the body's immune system attacking its own tissue, in this case the tissue forming the cortex of the adrenal glands. This causes the adrenal tissue to shrink (atrophy) and fail to produce the essential hormones.

Renin

A blood enzyme which causes vasoconstriction and increases blood pressure in the absence of aldosterone.

Sarcoidosis ‡

Is an inflammatory disease characterized by granulomas (small rounded outgrowths made up of blood vessels, cells and connective tissues) that can produce many different symptoms. It is generally a chronic disease, lasting for several years or a lifetime. Some people, however, may have a type that only lasts a few months.

Secondary adrenal insufficiency

Caused by a lack of ACTH (through disease or impairment to the pituitary gland), which causes a drop in the adrenal glands' production of cortisol, but not of aldosterone.

Secondary adrenal suppression

Steroid induced adrenal suppression. Normally caused by long-term treatment with steroids.

Sodium

An essential mineral in the blood which helps to maintain normal functioning muscles and nerves.

Steroid

A general term relating to either naturally occurring hormones produced by the adrenal glands, or their synthetic equivalents.

Steroid replacement therapy

The prescription of synthetic steroids used to replace deficiency in the body's natural production of these hormones.

Thyroid

A butterfly shaped endocrine gland situated in front and on either side of the trachea (windpipe). It secretes the hormones thyroxine (T4) and tri-iodothyronine (T3), which are concerned in regulating the metabolic rate.

Thyroid Stimulating Hormone (TSH)

A hormone produced by the pituitary gland which controls the activity of the thyroid gland.

Thyrotoxicosis

See Hyperthyroidism.

If there are other medical terms, encountered in context with Addison's Disease, that you would like explained, please ask via the e-mail link on the 'Contact us' page and we will do our best to assist.