Medical terms A–Z

Aldosterone is a hormone from the adrenal gland that regulates blood pressure by controlling how the kidneys retain sodium and release potassium.

The shorter name for a rare inherited triad, still turning up in older records long after the fuller version became standard.

A drug that is used to treat certain skin conditions and is being studied in the treatment of cutaneous (skin-related) T-cell cancer and T-cell non-Hodgkin lymphoma.

An antibody that strips lymphocytes out of the blood, used to reset an immune system attacking the nervous system.

Alendronate sodium is a bisphosphonate drug that slows bone breakdown, used mainly to treat osteoporosis and certain other bone conditions.

The brand name for pemetrexed, a chemotherapy drug given alongside two vitamins that blunt its harshest effects.

An alkali is a water soluble base capable of neutralizing acids, relevant in medicine to blood chemistry, chemical burns, and body pH balance.

Refers to the amount of alkali.

A process that lowers the amount of acid in a solution.

An alkaloid is a nitrogen containing compound found in many plants, including well known examples such as caffeine, nicotine, and morphine.

A drug that is used to treat multiple myeloma and ovarian epithelial cancer and is being studied in the treatment of other types of cancer.

The oldest family of chemotherapy drugs, acting by sticking chemical groups onto DNA so it can no longer be read.

A nutrient that that body needs in small amounts to function and stay healthy.

Allegra is the brand name for fexofenadine, a second-generation antihistamine that relieves allergy symptoms with less drowsiness than older allergy medications.

Something harmless in itself that a particular immune system has learned to treat as a threat.

A hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in most people.

A word describing where donated material came from: another person of the same species, neither the recipient nor an animal.

A procedure in which a person receives stem cells (cells from which all blood cells develop) from a genetically similar, but not identical, donor.

A variant spelling of a transplant term, describing tissue from another person and therefore tissue the immune system can tell apart.

Tissue moved from one person to another, which works well mechanically but is recognized as foreign by the recipient immune system.

Allopathic medicine is the conventional biomedical system built on drugs, surgery, and other interventions supported by scientific research, in contrast with alternative approaches.

Starting it can set off an attack, because a shifting uric acid level disturbs crystals already sitting in a joint.

A substance that is being studied as a gene therapy agent in the treatment of cancer.

A substance found in certain plants, including aloe vera.

The pattern of loss, and whether the follicle survives, matter more than the amount, because one determines whether hair can return.

An anti-sickness injection that holds onto its receptor far longer than the older drugs in the same class.

Alpha hydroxyl acids are naturally occurring organic acids used in skin care to promote surface cell turnover and improve skin texture.

A drug class that occupies the receptors adrenaline uses to squeeze blood vessels and the muscle at the bladder outlet.

Named for the receptor it occupies, this drug group loosens smooth muscle so vessels widen and urine flows more easily.

Alpha-fetoprotein is a protein made by a developing fetus, used both in prenatal screening and as a marker for certain cancers in adults.

Alpha-lipoic acid is a naturally occurring compound that helps cells convert nutrients into energy and also functions as an antioxidant.

Alprostadil, also known as prostaglandin E1, is used to treat erectile dysfunction and to keep a critical fetal blood vessel open in newborns.

Alteplase is a clot dissolving medication given intravenously within a defined time window after a stroke, heart attack, or major clot in the lungs.

A deliberately neutral word: it records that something has changed without claiming the change is harmful, inherited or permanent.

Alternative medicine refers to practices used in place of standard medical treatment that are not part of conventional care.

An anticancer drug that belongs to the family of drugs called alkylating agents.

Alum is an astringent mineral salt used to stop minor bleeding, treat minor skin irritation, and boost vaccine effectiveness.

A cancer vaccine made with a form of the canarypox virus that does not cause disease in people.

Alveolar rhabdomyosarcoma is a muscle related soft tissue cancer that tends to affect older children and adolescents and behaves more aggressively than the embryonal subtype.

A soft tissue tumor that is most common in older children and teenagers.

The alveoli present an enormous surface area within the lungs, a feature essential to allowing efficient gas exchange with each breath.

A substance being studied in the treatment of several types of cancer.

A brain disorder that usually starts in late middle age or old age and gets worse over time.

Two abnormal proteins, amyloid and tau, accumulate in the brain for years before any memory problem becomes obvious enough to notice.

Amanita phalloides is a highly toxic fungus responsible for most fatal mushroom poisonings, with symptoms that can appear deceptively delayed after ingestion.

A drug used to treat infections caused by the influenza A virus.

Short action is the design: it starts working quickly and clears before morning, which is also why it does little for staying asleep.

Reading, driving and recognizing faces all rely on the macula, and AMD is a leading cause of central vision loss in later life.

A drug used before autologous stem cell transplantation in patients with non-Hodgkin lymphoma or multiple myeloma.

Amelanotic melanoma is a form of skin cancer that lacks the dark pigment typical of melanoma, often appearing pink or red instead.

A drug used to treat some types of cancer, rheumatoid arthritis, and severe skin conditions, such as psoriasis.

A drug that is used to treat certain skin conditions and is being studied in the treatment of cutaneous (skin-related) T-cell cancer and T-cell non-Hodgkin lymphoma.

A substance being studied in the treatment of cancer.

A type of monoclonal antibody being studied in the treatment of multiple myeloma (a cancer that forms in bones) and in the prevention and treatment of bone metastases (cancer that has spread to bone…

A drug used to treat patients with immune thrombocytopenic purpura (ITP) who do not get better with other forms of treatment.

A substance that is being studied in the treatment of some types of cancer.

A drug used as a chemoprotective drug to control some of the side effects of chemotherapy and radiation therapy.

A reserve antibiotic for stubborn gram-negative bacteria, given by injection and watched closely for effects on hearing and kidneys.

Twenty of them, ordered by instructions copied from DNA, are enough to build every protein in the human body.

An amino acid sequence is the specific order of amino acids in a protein, determined by the corresponding gene.

A nutrient in the vitamin B complex that the body needs in small amounts to function and stay healthy.

An anticancer drug that belongs to the family of drugs called topoisomerase inhibitors.

An anticancer drug that belongs to the family of drugs called nonsteroidal aromatase inhibitors.

A substance that works against many types of bacteria and includes streptomycin, gentamicin, and neomycin.

A colorless building block that tumor cells convert into a red-glowing pigment, used both to reveal tissue and to destroy it.

A drug used to treat actinic keratosis (a skin condition that may become cancer).

An anticancer drug that belongs to the family of drugs called antimetabolites.

A drug used to treat certain types of abnormal heart rhythms that have not gotten better with other drugs.

Better known today for nerve pain, migraine and sleep than for depression, this older antidepressant acts on a wide range of receptors.

A drug that is used to treat depression and may be given to treat anxiety, sleep disorders, and pain.

AML is a fast progressing blood cancer in which immature white blood cells accumulate in the bone marrow, crowding out normal blood cell production.

A substance that is being studied in the treatment of cancer.

Amphotericin B remains an option for severe fungal infections even though its use requires balancing effectiveness against a recognized risk to the kidneys.

An ampulla is a localized, sac-like widening found along certain ducts or canals in the body, forming a distinct anatomical landmark.

An enlargement of the ducts from the liver and pancreas at the point where they enter the small intestine.

Cancer that forms in the ampulla of Vater (an enlargement of the ducts from the liver and pancreas where they join and enter the small intestine).

It sits at a narrow bottleneck, blocks bile early, and is often found while small, which is why it fares better than its neighbors.

Surgery to remove part or all of a limb or appendage.

A substance being studied in the treatment of lung cancer.

A bitter kernel compound sold as a cancer cure under the name laetrile, whose breakdown in the gut releases cyanide.

Amylase is an enzyme that breaks starch down into smaller sugars and is produced mainly by the salivary glands and pancreas.

What matters is which protein misfolded, because the answer sets the organs at risk, the likely course, and the treatment aimed at the source.

A type of steroid that is used in medicine to repair body tissues and to increase appetite and the growth of muscles.

A drug that is used to decrease the number of platelets in the blood in order to prevent blood clotting.

Having to do with the anus.

Anal cancer forms in tissue of the anus and is distinct from the more common rectal cancer, which affects the adjoining bowel segment.

A procedure in which cells are scraped from the lining of the anus (the opening of the rectum to the outside of the body) and looked at under a microscope.

A procedure in which cells are scraped from the lining of the anus (the opening of the rectum to the outside of the body) and looked at under a microscope.

Pain can be dulled while touch, movement and awareness stay intact, which is what separates it from being put under.

The classes act at different points along the pain pathway, which is why one may help where another does nothing.

Drug design usually starts from a molecule nature already built, alters one part of it, and keeps whatever the alteration improved.

A word that always needs a partner, since it names a habit of examination rather than any particular method, sample or test.

Anaphylactic shock is a severe, rapidly developing allergic reaction that can cause airway swelling, a sharp blood pressure drop, and circulatory collapse.

A pathologist's word for tumor cells so poorly formed that the tissue they grew out of can no longer be recognized.

An aggressive (fast-growing) type of non-Hodgkin lymphoma that is usually of the T-cell type.

A rare, aggressive type of thyroid cancer in which the malignant (cancer) cells look very different from normal thyroid cells.

An anastomosis is a connection joining two tubular structures, such as blood vessels or bowel segments, whether formed naturally or surgically.

Having to do with anatomy (the study of the structure of a plant or animal).

A person who specializes in anatomy (the study of the structures of animals or plants).

Anatomy is the branch of biological science that examines the structure of the body and how its parts are organized.