Glossary
Introduction
This Glossary explains some of the common medical and scientific words that are used when discussing HIV. For a more comprehensive glossary you may want to visit www.aidsmap.com
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Aids
Acquired Immune Deficiency Syndrome. A collection of specific illnesses and conditions which occur because the body's immune system has been damaged by HIV.
Antibody.
A protein substance produced by the immune system in response to a foreign organism.
Antiretroviral
A substance that acts against retroviruses such as HIV.
Buffalo hump
A build up of fat of the neck and shoulders, linked with hormonal changes and lipodystrophy.
Caesarean section
Method of birth where the child is delivered through a cut made in the womb.
Candidiasis or Candida
A disease caused by the fungi of the candida family such as Candida albicans. Commonly known as oral thrush.
CD4
A molecule on the surface of some cells onto which HIV can bind. This cell overseas the action of the immune system. The HIV virus infects the CD4 cells and they are destroyed, or they do not work properly. It is used as a marker of disease progression.
CD 4 Count
A test to establish the number of CD4 cells in a blood sample. The lower a persons CD4 the higher the chances of illness. CD4 can be affected by the time of day, health, smoking and menstrual cycle.
Cervix
The 'neck of the womb' at the top of the vagina.
Chronic
A long-term condition. HIV is often considered a long-term condition.
Clinical
A term referring to the nursing or medical care of patients.
Clinical trial
A research study involving participants, usually to find out how well a new drug or treatment works in people and how safe it is.
Clinician
A nurse or doctor who is active in looking after patients.
CMV
Cytomegalovirus, a virus that can cause blindness in people with advanced HIV disease.
CNS
Central nervous system.
Cohort
A group of people who share at least one common factor (e.g. being HIV-positive) and who are studied over a period of time.
Co-infection
Having more than one infection at the same time. For example, when a person with HIV has hepatitis B or C. This can make disease worse and treatment more difficult.
Combination therapy
The use of two or more drugs to fight infections. HAART (Highly Active Antiretroviral Therapy).
Compliance
An different term for adherence.
Cross resistance
The mechanism by which HIV that has developed resistance to one drug may also be resistant to other, similar drugs.
Crossover trial
A clinical trial where participants are switched from one arm to the other part way through.
Cryptosporidiosis
Infection with the gut parasite Cryptosporidium parvum and other species, causing severe diarrhoea.
Culture
Laboratory medium in which microbes can grow.
Dementia
Changes in mental function, co-ordination and personality resulting from direct effects of HIV infection in the brain.
Early intervention
Starting HIV treatment relatively early in the course of disease.
Efficacy
How well something works.
Encephalopathy
A disease or infection affecting the brain.
Erectile dysfunction
A man's inability to have or maintain an erection, also known as ED or impotence.
First-line therapy
The regimen used when starting treatment for the first time.
Foetus
An unborn baby.
Fungi
A group of organisms, including the yeasts which cause candidiasis and cryptococcosis.
Fusion inhibitor
Anti-HIV drug targeting the point where HIV locks on to an immune cell.
HAART
Highly Active Antiretroviral Therapy, a term used to describe anti-HIV combination therapy with three or more drugs.
Haematology
Study of blood conditions. Also used to describe a range of biochemical tests carried out on the blood.
Haemoglobin
Red-coloured, oxygen-carrying chemical in red blood cells.
Haemophilia
Inherited illness in which the blood does not always clot, often requiring injections of blood clotting agents.
Half-life
The amount of time it takes for half a dose of any drug to be eliminated from the body.
Helper cell
An alternative name for CD4 T cells or T helper cell.
Hepatic
To do with the liver.
Hepatitis
Inflammation or infection of the liver.
Hepatotoxicity
Side-effects affecting the liver.
Herpes simplex
A viral infection which may cause sores around the mouth or genitals.
Herpes viruses
Family of viruses which can cause disease in HIV infection, e.g. cytomegalovirus and herpes zoster.
Hickman line
A type of catheter that is surgically implanted, with one end leading into a large vein in the chest, and the other end remaining outside the chest.
HIV
Human immunodeficiency virus, the virus which causes AIDS. There are two variants: HIV-1, and HIV-2. HIV-1 is by far the most common world-wide.
HIV Test
The test is an HIV antibody test - it is to see if HIV antibodies are present in the blood. If antibodies are present then there has been exposure to HIV.
Homeopathy
A therapy which aims to treat illness using tiny quantities of the substance that caused the illness, or of a substance that causes similar symptoms.
Hormone
A chemical which stimulates or suppresses cell and tissue activity.
Human papilloma virus (HPV)
A group of wart-causing viruses which are also responsible for cancer of the cervix and some anal cancers.
Hyper
Prefix meaning higher than usual.
Hyperglycaemia
Raised concentration of sugar in the blood.
Hyperlipidaemia
High levels of fat in the blood.
Hypersensitivity
An allergic reaction.
Hypertension
Raised blood pressure.
Hypo
Prefix meaning lower than usual.
Hypoxaemia
Reduced amounts of oxygen in the blood, usually caused by pneumonia.
Immune reconstitution
Improvement of the function of the immune system as a consequence of anti-HIV therapy.
Immune system
The body's mechanisms for fighting infections and eradicating dysfunctional cells.
Immunoglobulin
Another name for antibodies.
Immunologic response
The effect of treatment on the immune system, particularly on the CD4 cell count.
Immunosuppression
A reduction in the ability of the immune system to fight infections or tumours.
In utero
Latin term meaning in the womb.
Inclusion criteria
The conditions which a person must meet to join a clinical trial.
Informed consent
Agreement to take part in a clinical trial, or to take a test, after a full written or verbal explanation of the trial including the risks and benefits of taking part, has been provided by the researchers.
Insomnia
Sleeplessness.
Insulin
A hormone produced by the pancreas that tends to lower blood sugar levels.
Integrase
HIV enzyme that the virus uses to insert its genetic material into that of an infected cell.
Interferon
A type of antiviral protein which stimulates the immune system.
Intramuscular
Injected into a muscle.
Intrapartum
During the birth of a baby.
Intravenous
Injected into a vein.
Invasive
In medical terms, going inside the body.
Jaundice
A yellowing of the skin and whites of the eyes associated with liver or gall bladder problems.
Kaposi's sarcoma
Lesions on the skin and/or internal organs caused by abnormal growth of blood vessels.
Lactate
Another name for lactic acid.
Lactic acidosis
High blood levels of lactic acid, a substance involved in metabolism. Lactic acidosis is a rare side-effect of nucleoside analogues.
Lesion
Any abnormal change in body tissue caused by disease or injury. Often refers to Kaposi's sarcoma, which can cause skin lesions.
Leukocytes
White blood cells.
Leukopenia
Fewer than normal white cells in the blood, usually due to bone marrow damage.
Leukoplakia
A mouth infection caused by Epstein-Barr virus that can occur relatively early in HIV disease. Often called hairy leukoplakia due to its appearance as white patches on the sides of the tongue.
Libido
Another word for sexual drive.
Lipid
A general term for fats.
Lipoatrophy
Loss of body fat.
Lipodystrophy
A disruption to the way the body produces, uses and distributes fat.
Liver
An organ involved in digestion of food and excretion of waste products from the body.
Liver function tests (LFTs)
Tests evaluating the functioning of the liver.
Lymph nodes
Special areas in the body where white blood cells and other important immune cells are found. Also known as glands.
Lymphadenopathy
A swelling of the lymph nodes.
Lymphocyte
A type of white blood cell.
Lymphocytic interstitial pneumonitis
A type of lung problem, most commonly seen in children with HIV infection.
Lymphoid tissue
Tissue involved in the formation of lymph fluid, lymphocytes and antibodies.
Lymphoma
A type of tumour affecting the lymph nodes.
Maintenance therapy
Taking drugs for a period of time after an infection has been treated, to stabilise the condition or prevent a re-occurrence or deterioration.
Malabsorption
Failure of the gut to absorb food, resulting in weight loss, diarrhoea and decreased effectiveness of drugs taken orally.
Monotherapy
Taking a drug on its own, as opposed to in combination with other drugs.
Myopathy
Muscle wastage or disease.
Naïve
Never having taken anti-HIV treatments before.
Named patient basis prescribing
A means of access to an unlicensed drug, in which a doctor requests supplies from its manufacturer for a specific individual.
Natural killer cells
Cells in the immune system which attack and destroy infected cells or tumour cells.
Nausea
Feeling sick.
Neoplasm
An abnormal and uncontrolled growth of tissue; a tumour.
Nephrotoxic
Damaging to the kidneys.
Neuralgia
A sharp pain along the path of a nerve.
Neurological
Relating to the brain or nervous system.
Neuropathy
Damage to the nerves.
NNRTI
Non nucleoside reverse transcriptase inhibitor, the family of antiretrovirals which includes efavirenz, nevirapine and delavirdine.
NRTI
Nucleoside analogue reverse transcriptase inhibitor, the family of antiretrovirals which includes AZT, ddI, 3TC, d4T, ddC and abacavir.
Nucleoside
One of the building blocks from which DNA and RNA are made.
Nucleoside analogue
Chemical which resembles a nucleoside. Family of antiretrovirals which includes AZT, ddI, 3TC, d4T, ddC and abacavir.
Nucleotide analogue
Chemical which resembles a nucleotide. Family of antiretrovirals which includes tenofovir.
A clinical trial which reports on an unfolding situation.
Obstetric
Relating to antenatal care.
Oedema
Accumulation of fluid below the skin or in the cavities of the body.
Oesophagus
The tube leading from the throat to the stomach.
OI
Opportunistic infection. opportunistic infection
Specific infections which cause disease in someone with a damaged immune system.
Paediatric
Of or relating to children.
Palliative
To do with relieving rather than curing symptoms.
Pancreas
A glandular organ situated behind the stomach that secretes insulin and pancreatic digestive enzymes.
Pancreatitis
A condition of the pancreas causing severe abdominal pain, shock and collapse, which can be fatal.
PAP smear
A specimen of cells from the cervix, usually obtained in scrapings from the opening, which may be examined by microscope to look for abnormalities.
Paraesthesia
Abnormal sensations of touch on the skin.
Pathogen
Any micro-organism which can cause disease. There are four main types: bacteria, fungi, protozoa, viruses.
PCP
Pneumocystis carinii pneumonia, a form of pneumonia, which is an IDS defining illness.
PCR
Polymerase chain reaction, a method of amplifying fragments of genetic material so that they can be detected. Some viral load tests use this method.
Perianal
Around the anus.
Perinatal
Around the time of birth.
Peripheral neuropathy
Damage to the nerves of the hands and/or feet, causing symptoms ranging from numbness to excruciating pain.
PI
See protease inhibitor.
Placebo
A pill or liquid which looks and tastes exactly like a real drug, but contains no active substance.
Plasma
The fluid portion of the blood.
PML
Progressive multifocal leukoencephalopathy, a serious brain infection.
Poppers
Amyl, butyl or isobutyl nitrite, are recreational drugs sniffed during sex to both intensify the experience and relax anal sphincter muscles.
Preclinical
Of in vitro research or research involving animals, undertaken prior to research in humans.
Primary infection
The first few weeks after infection, e.g. with HIV.
Pro-drug
A drug that is broken down into another active form inside the body.
Prognosis
Likely outcome, such as the risk of disease progression.
Prophylaxis
Taking a drug to prevent an illness. Primary prophylaxis is the use of drugs to prevent a first occurrence of illness. Secondary prophylaxis is the use of drugs to prevent re-occurrence of illness.
Protease
An enzyme that HIV uses to break up large proteins into smaller ones from which new HIV particles can be made.
Protease inhibitor
Family of antiretrovirals which target the protease enzyme. Includes amprenavir, indinavir, lopinavir, ritonavir, saquinavir, nelfinavir, and atazanavir.
Protein
A substance which forms the structure of most cells and enzymes.
Psoriasis
A disease in which the skin develops raised, rough, reddened areas.
Psychiatry
A branch of medicine that treats people, using drugs and other physical methods, to change the way they act and feel.
Psychology
A branch of medicine that tries to explain why people act, think and feel the way they do.
Pulmonary
Affecting the lungs.
Radiotherapy
Treatment using radium or other radioactive matter.
Rectum
The last part of the large intestine just above the anus.
Regimen
A drug or treatment combination and the way it is taken.
Regression
Improvement in a tumour.
Remission
Partial recovery from an illness, an alternative word for regression.
Renal
Relating to the kidneys.
Replication
The process of viral reproduction.
Resistance
A drug-resistant HIV strain is one which is less susceptible to the effects of one or more anti-HIV drugs because of its genotype.
Retrovirus
Family of viruses to which HIV belongs, that are distinguished by their use of RNA.
Reverse transcriptase
A retroviral enzyme which converts genetic material from RNA into DNA, an essential step in the lifecycle of HIV.
RNA
Ribonucleic acid, the form in which HIV stores its genetic material. salvage
therapy
Any treatment regimen used after a number of earlier regimens have failed.
Seroconversion
The time at which a person's antibody status changes from negative to positive.
Seronegative
Negative antibody result in a blood test.
Seropositive
Positive antibody result in a blood test.
Serum
Clear, non-cellular portion of the blood, containing antibodies and other proteins and chemicals.
Shingles
Condition caused by a herpes virus infection, involving painful blisters on the skin.
Simian
Related to or affecting monkeys.
Sinusitis
Inflammation or infection of the sinuses, which are cavities behind the forehead and cheekbones.
Speculum
An instrument for enlarging the opening of any canal or cavity in order to inspect its interior, e.g. vagina, rectum, ear or nose.
Spleen
Organ which produces white blood cells and acts as a reservoir for red blood cells.
Steroids
Drugs used to damp down excessive immune responses.
Strain
A variant characterised by a specific genotype.
Subcutaneous
Beneath or introduced beneath the skin, e.g. a subcutaneous injection is an injection beneath the skin.
Subtype
Different strains of HIV which can be grouped according to their genes.
Superinfection
When somebody already infected with HIV is exposed to a different strain of HIV and becomes infected with it in addition to their exisitng virus.
Surrogate marker
An indirect indicator of something, such as measuring viral load to assess the treatment effect of a drug.
Symptom
A condition that results from or accompanies an illness or disease.
Symptomatic
Having symptoms.
Syndrome
A collection of symptoms and diseases that together are characteristic of a specific condition.
T cell
A type of immune system cell which is damaged in the course of HIV infection. CD4 and CD8 cells are both sub-types of T cell.
T helper cells
T cells that alert the immune system to produce cytotoxic T lymphocytes against a specific infection. Also known as CD4 cells
TB
Short for Tuberculosis.
Teratogenic
Causing physical defects in the foetus.
Therapeutic vaccine
A vaccine-like product used with the aim of improving the immune function of someone who already has an infection, rather than of preventing the infection.
Thrush
A fungal infection of the mouth, throat or genitals, marked by white patches. Also called candidiasis.
Thymus
A gland in the chest where T cells produced in the bone marrow mature into effective immune system components.
Tonsils
Two oval lymph node-like structures situated where the mouth joins the throat.
Topical
Applied directly to the affected area, as opposed to systemic.
Toxicity
The extent or ways in which a drug is poisonous to the body.
Toxin
A poisonous substance.
Toxoplasmosis
A disease due to infection with the parasite Toxoplasma gondii, usually causing inflammation of the brain.
Trough level
The lowest point to which levels of a drug fall in the blood between doses.
Tuberculosis
TB, is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria can attack any part of your body, but they usually attack the lungs. TB is spread through the air from one person to another. The bacteria are put into the air when a person with TB disease of the lungs or throat coughs or sneezes.
Tumour
Growth of tissues that perform no useful function, sometimes due to cancer.
Ulcer
A break in the skin or mucous membrane which involves the loss of the surface tissue.
Undetectable viral load
A level of viral load that is too low to be picked up by the particular viral load test being used.
Vaccine
A substance that contains antigenic components from an infectious organism. By stimulating an immune response (but not disease), it protects against subsequent infection by that organism, or may direct an immune response against an established infection or cancer.
Vertical transmission
Transmission, for example of HIV, from mother-to-baby.
Viraemia
The presence of virus in the blood.
Viral load
Measurement of the amount of virus in a sample. HIV viral load indicates the extent to which HIV is reproducing in the body.
Virion
A virus particle existing freely outside a host cell.
Virologic response
The effect of treatment on viral load.
Virulence
The power of bacteria or viruses to cause a disease. Different strains of the same micro-organism can vary in virulence.
Virus
A microscopic germ which reproduces within the living cells of the organism it infects.
Vulva
The external female genitals.
Virological relapse
When viral load can be measured after previously being undectectable.
White blood cell
The cells of the immune system, including basophils, lymphocytes, neutrophils, macrophages and monocytes.
Wild-type virus
Virus that has not been exposed to anti-HIV drugs before.
Wasting
Muscle and fat loss.