Medical terms - Letter A
1,573 terms start with the letter A.
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Acoustic neuroma
A benign tumor that may develop on the hearing and balance nerves near the inner ear. The tumor results from an overproduction of Schwann cells -- small sheet-like cells that normally wrap around nerve fibers like onion…
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ACP (American College of Physicians)
See: American College of Physicians
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Acquired
Anything that is not present at birth but develops some time later. In medicine, the word 'acquired' implies 'new' or 'added.' An acquired condition is 'new' in the sense that it is not genetic (inherited) and 'added'…
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Acquired deafness
Deafness: The loss of hearing that occurs or develops some time during a person's life but was not present at birth. Acquired deafness contrasts to congenital deafness which is present at birth. The distinction between…
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Acquired epileptiform aphasia
See Landau-Kleffner syndrome
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Acquired immunity
Immunity acquired by infection or vaccination (active immunity) or by the transfer of antibody or lymphocytes from an immune donor (passive immunity). Acquired immunity is in contrast to innate immunity (natural…
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Acquired immunodeficiency syndrome
AIDS. AIDS is a disease due to infection with the human immunodeficiency virus (HIV). Also referred to as acquired immunodeficiency disease
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Acquired mutation
A mutation (a genetic change) acquired by a somatic cell after conception. Acquired mutations occur in somatic cells, not germ cells, and so cannot be transmitted to the children. However, acquired mutations are…
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Acral-lentiginous melanoma
See: Melanoma, acral-lentiginous
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Acrocentric chromosome
A chromosome (one of the microscopically visible carriers of the genetic material DNA) with its centromere (the 'waist' of the chromosome) located quite near one end of the chromosome. The 'acro-' in acrocentric comes…
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Acrocephalosyndactyly
An inherited disorder causing abnormalities of the skull and face and the hands and feet. In acrocephalosyndactyly there is closure too-early of some of the sutures of the skull (craniosynostosis). This results in an…
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Acrochordon
A small tag of skin that may have a stalk (a peduncle). An acrochordon may appear on skin anywhere although the favorite locales are the eyelids, neck, armpits (axillae), upper chest, and groin. Invariably benign, this…
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Acrocyanosis
Blueness of the extremities (the hands and feet). Acrocyanosis is typically symmetrical. It is marked by a mottled blue or red discoloration of the skin of the fingers and wrists and the toes and ankles and by profuse…
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Acrodermatitis enteropathica
An historic model for the therapy of genetic disease. In an era (the 1950s) when inherited disorders were usually seen as hopeless, this progressive hereditary (autosomal recessive) disease of children was found…
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Acrodynia
Pain in the extremities (the hands and feet)
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Acromegaly
Condition due to the production of too much growth hormone by the pituitary gland after the end of adolescence. When there is secretion of too much growth hormone before the end of adolescence, gigantism results. People…
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Acromioclavicular joint
The acromioclavicular (AC) joint is located between the acromion (a projection of the scapula that forms the point of the shoulder) and the clavicle (the collar bone). This is a gliding type of joint. The ligaments that…
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Acromion
The projection of the scapula (the shoulder blade) that forms the point of the shoulder. The acromion is part of the scapula. It protrudes laterally (away from the midline) and is triangular in shape. The top of the…
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Acrophobia
An abnormally excessive and persistent fear of heights. Sufferers experience severe anxiety even though they usually realize that, as a rule, heights pose no real threat to them. Derived from the Greek 'acron', height +…
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Acrylamide
A chemical created in foods when starches and other carbohydrates are overheated (over 120°C or 250°F) during cooking. There is concern that acrylamide may be a carcinogen (cause cancer). Acrylamide is used in…
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ACS (American Cancer Society)
A 'nationwide community-based voluntary health organization dedicated to eliminating cancer as a major health problem by preventing cancer, saving lives and diminishing suffering from cancer through research, education…
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ACS (American College of Surgeons)
The American College of Surgeons was formed in 1913 under the aegis of Dr. John Miller Turpin Finney 'to elevate the standard of surgery, to establish a standard of competency and of character for practitioners of…
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Actinic
Referring to the ultraviolet (UV) rays from sunlight and UV lamps. Sunburn is an actinic burn. An actinic keratosis is a skin lesion that is the consequence of chronic sun exposure. From the Greek 'aktis' meaning 'ray.
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Actinic keratosis
Our Actinic keratosis Main Article provides a comprehensive look at the who, what, when and how of Actinic keratosis Actinic keratosis: A small rough spot on skin chronically exposed to the sun, precancerous, can…
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Actinomycetes
A group of gram-positive bacteria (order Actinomycetales) that produce various bioactive agents including antibiotics, enzymes, and vitamins. Streptomyces belong to this bacterial order
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Activase
Brand name of alteplase, a tissue plasminogen activator made by recombinant DNA technology. See: Tissue plasminogen activator
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Activated charcoal
Charcoal that has been heated to increase its absorptive capacity. Activated charcoal is sold as an over-the-counter (OTC) product to help relieve intestinal gas. It is also used to absorb poisons (as in gas mask…
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Activated leukocyte cell adhesion molecule
See: ALCAM
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Active euthanasia
The active acceleration of a 'good' death by use of drugs etc, whether by oneself or with the aid of a doctor. The word 'euthanasia' comes from the Greek -- 'eu' meaning 'goodly or well' + 'thanatos' meaning 'death.'…
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Active immunity
The production of antibodies against a specific agent by the immune system. Active immunity can be acquired in two ways: > >by contracting an infectious disease -- such as, for example, chickenpox; or >by receiving a…
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Active tuberculosis
See: Tuberculosis, active
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Activities of daily living (ADLs)
The things we normally do in daily living including any daily activity we perform for self-care (such as feeding ourselves, bathing, dressing, grooming), work, homemaking, and leisure. The ability or inability to…
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Activity, drug
A measure of the physiological response a drug produces in the body. A less active drug produces less response (and visa versa)
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Acu-
A combining form indicating a relationship to a needle. As in acupuncture. From the Latin acus meaning needle
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Acuity test, visual
This test measures how well you see at various distances. It is the familiar eye chart test. The eye chart itself -- the usual one is called Snellen's chart -- is imprinted with block letters that line-by-line decrease…
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Acuity, auditory
The clarity or clearness of hearing, a measure of how well a person hears and monitoring the ability to hear. The word 'acuity' comes from the Latin 'acuitas' = sharpness.
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Acuity, visual
The clarity or clearness of the vision, a measure of how well a person sees. The ability to distinguish details and shapes of objects; also called central vision. The word 'acuity' comes from the Latin 'acuitas' =…
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Acupressure
The application of pressure on specific points on the body to control symptoms such as pain or nausea. Similar in concept to acupuncture but without needles
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Acupuncture
Our Acupuncture Main Article provides a comprehensive look at the who, what, when and how of Acupuncture Acupuncture: The practice of inserting needles into the body to reduce pain or induce anesthesia. More broadly…
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Acupuncturist
A person skilled in the practice of acupuncture, who may or may not be credentialed by a national accrediting body
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Acustimulation
Mild electrical stimulation of acupuncture points done to control symptoms such as nausea and vomiting
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Acute
Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care. 'Acute' is a measure of the time scale of a disease and is in…
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Acute abdomen
The abrupt (acute) onset of abdominal pain. A potential medical emergency, an acute abdomen may reflect a major problem with one of the organs in the abdomen such as the appendix (being inflamed = appendicitis), the…
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Acute angle-closure glaucoma
Increased pressure in the front chamber (anterior chamber) of the eye due to sudden (acute) blockage of the normal circulation of fluid within the eye. The block takes place at the angle of the anterior chamber formed…
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Acute bacterial prostatitis
Prostatitis: Inflammation of the prostate gland of sudden (acute) onset due to bacterial infection. The symptoms include chills, fever, pain in the lower back and genital area, body aches, burning or painful urination…
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Acute brain syndrome
See: Delirium
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Acute confusional state
See: Delirium
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Acute coronary syndromes
A spectrum of conditions involving chest discomfort or other symptoms caused by lack of oxygen to the heart muscle (the myocardium). The unification of these manifestations of coronary artery disease under a single term…
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Acute epiglottitis
A very rapidly progressive infection causing inflammation of the epiglottis (the flap that covers the trachea) and tissues around the epiglottis that may lead to abrupt blockage of the upper airway and death. The…
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Acute fatty liver of pregnancy
Fatty liver of pregnancy: Liver failure in late pregnancy, usually from unknown cause. Acute fatty liver of pregnancy (AFLP) typically occurs in first-time pregnancies in the last trimester. AFLP causes nausea and…