Antigen

Any substance which is capable, under appropriate conditions, of inducing a specific immune response and of reacting with the products of that response, that is, with specific antibody or specifically sensitised T-lymphocytes, or both.

Antibody

An immunoglobulin molecule that has a specific amino acid sequence by virtue of which it interacts only with the antigen that induced its synthesis in cells of the lymphoid series (especially plasma cells), or with antigen closely related to it.

Bacterium

A one-celled organism without a true nucleus or functionally specific components of metabolism that belongs to the kingdom Procaryotae (Monera). The internal cytoplasm surrounded by a one or two-layered rigid cell wall composed of phospholipids.

Virus

Small living particle (much smaller than bacteria) that can infect cells and change how the cells function. Infection with a virus can cause a person to develop symptoms. A virus is a sub-cellular entity composed merely of genetic material (DNA or RNA) surrounded by a protein envelope. Viruses can reproduce only within living cells into which they inject their genetic material. The viral genes then subvert an infected cell's normal chemical processes to create new virus particles, usually killing the cell in the process. The disease and symptoms that are caused depend on the type of virus and the type of cells that are infected.

Angina

Severe pain around the heart caused by a relative deficiency of oxygen supply to the heart muscle. It occurs most often after increased activity, exercise or a stressful event. Pain or numbness typically radiates to the left shoulder and down the left arm.

Arteriosclerosis

Condition in which the walls of arteries become hard and thick, sometimes interfering with blood circulation.

Cardiomyopathy

Disease of the myocardium especially that caused by primary disease of the heart muscle.

Cerebrovascular disease

A disease which affects an artery's ability to supply blood to the brain. See also stroke.

Coronary heart disease

See ischaemic heart disease.

Heart attack

See myocardial infarction.

(Congestive) heart failure

The inability of the heart to pump blood effectively; characterised by fluid collecting in various parts of the body, typically legs, but also lungs and liver.

Ischaemic heart disease

Narrowing or blockage of one or more of the coronary arteries resulting in decreased blood supply to the heart (ischaemia).

High blood pressure

A condition forcing the heart to pump blood through the circulatory system at a force much greater than is necessary to maintain a steady flow. See also hypertension.

Hypertension

Condition in which the blood is pumped through the body under abnormally high pressure; see also high blood pressure.

Ischaemia

A condition in which a tissue or organ does not receive a sufficient supply of blood.

(Acute) myocardial infarction

The death of an area of heart muscle as a result of the blockage of one or more of the coronary arteries resulting in interruption of blood flow to that part of the heart; characterised by severe pain in the chest; commonly known as heart attack.

Peripheral vascular disease

The narrowing of blood vessels in the legs or arms, causing pain and possibly tissue death (gangrene) as a result of a reduced flow of blood to areas supplied by the narrowed vessels.

Rheumatic fever

A disorder that may follow a streptococcal throat infection; characterised by an inflammatory response that may cause arthritis and, more importantly, damage to the heart valves.

Rheumatic heart disease

One of the complications of rheumatic fever involving irreversible damage to the heart valves.

Stroke

An injury of the brain due to bleeding or to an interruption of the blood supply.

Asthma

Condition characterised by constriction or congestion of the bronchial tubes, associated with wheezing, coughing and difficult breathing.

Chronic bronchitis

Marked by increased mucus secretion by the tracheo-bronchial tree. The productive cough is usually present for at least three months of two consecutive years. The diagnosis can be made only if bronchopulmonary diseases such as bronchiectasis, tuberculosis, and tumor have been excluded.

Chronic obstructive airways (pulmonary) disease

A disease process that decreases the ability of the lungs to perform ventilation. Diagnostic criteria include a history of persistent dyspnea on exertion with or without chronic cough and less than half of normal predicted maximum breathing capacity. Diseases that cause this condition are chronic bronchitis, pulmonary emphsema, chronic asthma and chronic bronchiolitis.

Emphysema

1.Pathological distention of interstitial tissues by gas or air. 2. A chronic pulmonary disease marked by an abnormal increase in the size of air spaces distal to the terminal bronchiole with destructive changes in their walls.

Influenza

An acute viral infection involving the respiratory tract; characterised by inflammation of the nasal mucosa, pharynx, and conjunctiva, and by headache and severe, often generalised myalgia. Damage to bronchial membranes results in susceptibility of patients to secondary bacterial infections.

Pneumonia

An inflammation of the alveoli, interstitual tissue and bronchioles of the lungs due to infection by bacteria, viruses or other pathogenic organisms or to irritation by chemicals or other agents (eg oil, radiation, drugs).

Diabetes mellitus

A condition where the pancreas produces insufficient or no insulin, a hormone which controls sugar levels in the blood. Without insulin, the blood cannot absorb sugar into cells for energy and into liver and fat cells for storage.

Gestational diabetes

Diabetes that develops during pregnancy. The hormones secreted during pregnancy cause the mother's blood sugar to rise, and the mother cannot produce enough insulin to handle these higher levels. Gestational diabetes usually goes away after pregnancy, but about 60 percent of women who've had it eventually develop NIDDM.

Hypoglycemia

A condition in which blood glucose levels drop too low; also called insulin reaction or insulin shock.

Impaired glucose tolerance

A condition diagnosed when a glucose tolerance test shows that a person's blood sugar level is between normal and diabetic; people with this condition have a greater chance of developing the illness.

Insulin

A hormone made by the pancreas or taken by injection that regulates the amount of sugar (glucose) in the bloodstream.

Insulin-dependent diabetes mellitus (IDDM)

(or Type I diabetes; formerly called juvenile diabetes): a form of diabetes that often shows up before 30 years of age but may occur at any age; usually caused when the immune system attacks the beta cells of the pancreas and the pancreas can no longer produce insulin. People who have IDDM must take insulin injections to survive.

Non-insulin-dependent diabetes mellitus (NIDDM)

(or Type II diabetes; formerly called adult-onset diabetes) a form of diabetes that usually occurs in people over 40 years but may develop in younger people. Most people who develop NIDDM are insulin-resistant--that is, the pancreas makes enough insulin but the body's cells don't respond to it properly. Some people, however, simply cannot produce enough insulin to meet their body's needs. Others have a combination of these problems. Most people with NIDDM control it through diet and exercise, but some must also take pills or insulin injections. Ninety per cent of people with diabetes have NIDDM.

Acute post-streptococcal glomerulonephritis

An acute form of glomerulonephritis following infections caused by particular strains of streptococci.

Acute renal failure

Acute failure of the kidney to perform its essential functions. It may be due to trauma; any condition that impairs the flow of blood to the kidneys; certain toxic substances such as mercury compounds, carbon tetrachloride, or ethylene glycol; bacterial toxins; glomerulonephritis; or acute obstruction of the urinart tract.

End-stage renal disease (ESRD)

The final phase of kidney disease; treated by dialysis or kidney transplantation. See also: Dialysis; nephropathy.

Glomerulonephritis

A form of nephritis in which the lesions involve primarily the glomeruli. This condition may be acute, subacute or chronic. Acute glomerulonephritis, also known as acute nephritic syndrome, frequently follows infections, especially those of the skin and upper respiratory tract caused by particular strains of streptococci.

Kidneys

Two bean-shaped organs located in the back portion of the upper abdomen that are responsible for excreting urine and regulating the water and chemical contents of the blood.

Pyelonephritis

Inflamation of kidney and renal pelvis, usually due to bacteria that have ascended from the bladder after entering through the urethra.

Renal disease

The inability of the kidneys to excrete wastes, concentrate urine and maintain electrolyte balance.

Body mass index (BMI )

A key index for relating weight to height. BMI is weight in kilograms (kg) divided by height in meters (m) squared.

Failure to thrive

A condition in which infants and children not only fail to gain weight but also may lose it. The organic causes include almost any severe chronic or recurrent condition (including infections). The causes of nonorganic failure to thrive include starvation, emotional deprivation, and social deprivation.

Fibre

As applies to food, a substance that resists digestion and passes through the system essentially unchanged. Fibre adds bulk to the diet and aids in elimination.

Intra-uterine growth retardation (IUGR)

A decreased rate of fetal growth. The infant's birthweight is below the 10th percentile on the intrauterine growth curve for the calculated gestation period. This may be the result of any condition that interferes with the blood supply to or state of health of the placenta or the general health or nutrition of the mother.

Low birthweight

Birthweight of less than 2,500 grams.

Obesity

Abnormal body weight, defined in Australia as a body mass index of 30 or more.

Overweight

Slightly abnormal body weight, defined in Australia as a body mass index of 25 or more and less than 30.

Small for gestational age (SGA)

The term describing an infant whose birthweight is less than would be considered normal for the length of the calculated gestation period.

Nutrition

All the processes involved in the taking in and utilisation of food substances by which growth, repair and maintenance of activities in the body as a whole or in any of its parts are accomplished. These processes include ingestion, digestion, absorption, and metabolism.

Benign

Not cancerous; does not invade nearby tissue or spread to other parts of the body.

Cancer

Diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can metastasise (spread) through the bloodstream and lymphatic system to other parts of the body.

Carcinoma

Cancer that begins in the lining or covering of an organ.

Lymphoma

Any neoplastic disorder of the lymphoid tissue; used alone, the term is used to denote malignant lymphoma.

Malignant

Cancerous; can spread to other parts of the body.

Metastasis

The transfer of disease from one organ or part to another not directly connected with it.

Oncogenes

Genes present in normal cells that, upon exposure to cancer-inducing factors may lead to development of tumors.

Tumor

Abnormal mass of tissue; can be cancerous or benign.

AIDS (Acquired Immunodeficiency syndrome)

The late stage of the illness triggered by infection with human immunodeficiency virus (HIV); the diagnosis of AIDS is made when the person has a CD4 (helper T-cell) count of less that 200 and/or certain opportunistic infections common with advanced immune deficiency.

Chlamydia

A group of micro-organisms that causes various infections in humans, including trachoma and genital disease (Chlamydia is the most common sexually transmitted disease in Australia); can be treated with antibiotics.

Donovanosis

A granulomatous ulcerative disease in which the initial lesion commonly appears in the genital area as a painless nodule.

Gastroenteritis

An inflamatory condition of the stomach and intestines leading to nausea, vomiting, abdominal pain and diarrhea. Usually of bacterial or viral origin.

Gonorrhea

A contagious bacterial infection spread through sexual contact, including vaginal, oral or anal sex; one of the most common infectious diseases in the world; can be treated with antibiotics.

Haemophilus influenzae type B (HIB)

An important cause of meningitis, unusually in infants. In children this organism also causes acute epiglottitis pneumonia, septic arthritis and cellulitis.

Hepatitis

Inflammation of the liver caused by microbes or chemicals. Can be accompanied by jaundice, enlarged liver, fever, fatigue and nausea and high levels of liver enzymes in the blood.

Hepatitis A

. A self-limiting virus-induced liver disease; most commonly acquired through ingesting faecally contaminated water or food.

Hepatitis B

A viral infection which attacks the liver and causes inflammation; can be transmitted vertically (from mother to baby) or horizontally (most commonly through sexual intercourse, or by exchange of blood - by needle sharing among drug users, razor sharing.

Hepatitis C

A viral infection which attacks the liver and causes inflammation; transmitted most commonly by exchange of blood, particularly through needle sharing among drug users.

Hepatitis D

A form of hepatitis which appears to only cause symptoms when an individual is already infected with hepatitis B.

Herpes (simplex)

Virus causing small, painful skin blisters around the lips; genital herpes causes blisters on the sex organs.

HIV (Human immunodeficiency virus)

A virus which can destroy the immune system and lead to AIDS.

Leprosy

A chronic communicable disease caused by the acid-fast Mycobacterium leprae. It may occur at any age and in various clinical forms. The two principal forms are lepromatous and tuberculoid.

Meningitis

An inflammation of the meninges (the protective covering around the brain and spinal cord) usually accompanied by stiff neck and extreme sensitivity to light.

Scabies

A highly communicable skin disease caused by an arachnid Sarcoptes scabiei, variety hominis, the itch mite.

Sexually transmitted disease (STD)

Any infection that is acquired through sexual contact in a substantial number of cases.

Streptococcus

The most common disease-causing bacteria in humans which can be treated with antibiotics. If left untreated, some types of streptococcal bacteria may give rise to more serious diseases.

Syphilis

A sexually transmitted disease caused by bacteria which invade the blood through broken tissue linings in the sex organs, rectum, or mouth; can be treated with antibiotics.

Tuberculosis (TB)

A lung infection that occurs most frequently in people with weakened immune systems. TB can be easily passed to others and can lead to death if not treated.

Caries

Decay of tooth or bone; also known as cavities.

Dental plaque

A soft, thin film of food debris, mucin, and dead epithelial cells deposited on the teeth, providing the medium for the growth of various bacteria. Plaque plays an important role in the development of dental caries and periodontal and gingival diseases.

Periodontal

Pertaining to the area immediately around a tooth.

Periodontal disease

A disease of the supporting structures of the teeth, the periodontium, including alveolar bone to which the teeth are anchored. The most common symptom is bleeding gums, but loosening of teeth, receding gums, abscesses in pockets between gums and the teeth, and necrotising ulcerative gingivitis may be present as the disease process continues.

Alcoholism

A disorder characterised by pathological pattern of alcohol use that causes a serious impairment in social or occupational functioning. (In DSN III-R this is termed alcohol abuse or, if tolerance or withdrawal is present, alcohol dependence).

Kava

A Polynesian beverage made from the root of the plant, Piper methysticum. It has the effect of a tranquiliser and muscle relaxant with caffeine-like properties.

Deafness

Complete or partial loss of the ability to hear. Some forms of conductive deafness may be remedied by a fenestration operation or stapes mobilisation.

Otitis media

Inflammation of the middle ear (between the eardrum and inner ear) because of the spread of an infection from the nose, sinuses, and throat.

Blindness

Inability to see. The leading causes in Australia are cataracts, glaucoma and age-related macular degeneration.

Cataract

An opacity of the crystalline lens of the eye, which can prevent light from reaching the retina at the back of the eye. Cataract is increasingly frequent as people grow older and its occurrence doubles with each decade after the age of 40 years. Cataract develops progressively. At an early stage, cataract may only reduce vision a little, but with time a mature cataract can cause marked blindness. Because a cataract forms in the lens of the eye, the eye will not focus properly after cataract surgery without a replacement lens. An intraocular lens is now implanted at the time of surgery for this purpose. The quality of vision after modern cataract/intraocular lens surgery is usually excellent, although normal bifocal glasses are usually needed.

Glaucoma

A condition where abnormally high pressure of the fluid in the eye causes damage.

Retinopathy

Damage to small blood vessels in the eye's retina, which has a variety of causes (including diabetes). Diabetic retinopathy is characterised by the presence of retinal microvascular lesions. The earliest lesions visible with an ophthalmoscope are termed non-proliferative retinopathy, including microaneurysms, haemorrhages, hard exudates, cotton wool spots, intraretinal microvascular abnormalities and venous beading. The proliferative stage is characterised by growth of new vessels and fibrous tissue and pre-retinal and vitreous haemorrhage. Leak from macular capillaries results in macular oedema, and when present close to the central macula, is termed clinically significant macular oedema.

Non-proliferative diabetic retinopathy is not vision-threatening, but may proceed to proliferative diabetic retinopathy, which is.

Trachoma

Trachoma is a form of conjunctivitis caused by the bacterium, Chlamydia trachomatis. The initial form of the disease, follicular trachoma, is largely a disease of childhood and early adolescence with a peak prevalence in children aged 2 to 3 years. Long-standing and moderately severe follicular trachoma can lead to cicatricial trachoma, involving scarring and other damage to the eyelids and eyes. Severe scarring of the eyelids and in-turning of the eyelashes (trichiasis) can lead to opacification of the cornea and blindness.

Neurosis

Relatively mild emotional disorders (such as anxiety, mild depression and phobias).

Psychosis

A mental disorder in which a serious inability to think, perceive, and judge clearly causes loss of touch with reality.