totalhealth Medical Terms Dictionary » A

Medical terms and words can be alarming and can make understanding your condition difficult. Your doctor may have given you a diagnosis you do not understand or are unsure about.

At totalhealth we are committed to the aim of helping everyone to take control of their own health and treatment choices; for this reason we have compiled a comprehensive medical terms dictionary that we hope will be of real assistance.

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  • A&EAn abbreviation for accident and emergency
  • a1-antitrypsin deficiencyA disease caused by reduced or abnormal production in the body of a particular chemical.
  • abdomenThe part of the body that contains the stomach, intestines, liver, gallbladder and other organs.
  • abdominalRelating to the abdomen, which is the region of the body between the chest and the pelvis.
  • abdominal anginaIntermittent abdominal pain, frequently occurring after eating, caused by insufficient blood supply to the abdomen
  • abdominal cavityThe part of the body that contains the stomach, intestines, liver, gallbladder and other organs.
  • abdominal obesityObesity centred around the abdomen, resulting in a high waist circumference.
  • ABPIAn abbreviation for ankle brachial pressure index
  • abruptionPlacental lining separates from the uterus.
  • abscessInfection resulting in a collection of pus walled off by inflamed tissues.
  • acanthiosis nigracansA rare condition in which thickened dark patches of skin appear in the groin, armpits, neck and other skin-folds.
  • acanthosis nigricansA rare condition in which dark patches of skin appear in the groin, armpits, neck and other skin folds.
  • ACEAn abbreviation for angiotensin-converting enzyme
  • ACE inhibitorAbbreviation for angiotensin converting enzyme inhibitor - one of a class of drugs used to treat cardiovascular conditions.
  • acellularContaining no cells.
  • acetylcholinesterase inhibitorsA group of drugs that increase the levels of a chemical called acetylcholine.
  • achalasiaFailure of the muscle around the lower opening of the oesophagus (the lower oesophageal sphincter) to relax.
  • Achilles tendonThe tendon that connects the heel to the muscles of the lower leg.
  • acneInflammation of the oil-producing glands of the skin, leading to spots that may be pus-filled on the face and sometimes the upper body. It classically affects adolescents although it can occur at any age.
  • acoustic neuromaA rare, non-cancerous tumour arising from the cells surrounding the auditory nerve.
  • acromegalyA condition in which excess production of growth hormone from the pituitary gland in the brain after puberty causes excess growth, especially enlargement of the bones of the hands, feet and jaw
  • ACTHAn abbreviation for adrenocorticotrophic hormone
  • ActinomycesA type of bacteria.
  • actinomycosisA bacterial disease causing multiple swellings that may leak pus
  • acupressureA complementary therapy derived from acupuncture, which uses finger pressure rather than the fine sterile needles used in acupuncture.
  • acupunctureA complementary therapy in which fine sterile needles are inserted into the skin at specific points.
  • acuteHas a sudden onset.
  • acute abdomenA condition where there is sudden, severe abdominal pain requiring medical attention.
  • acute coronary syndromeA range of clinical conditions caused by coronary artery disease: it encompasses the full spectrum from unstable angina to heart attack.
  • acute lymphoblastic leukaemiaA type of leukaemia that is most common in the one to five age group.
  • acute myeloid leukaemiaA type of leukaemia that occurs most commonly in the over 50 age group.
  • acute respiratory distress syndromeExtreme difficulty breathing due to fluid accumulation in the alveoli of the lungs, causing sudden failure of the respiratory system. It may be fatal.
  • acute serum testA virological test.
  • Addison's diseaseA rare disorder where the adrenal glands, which are involved in a large range of bodily systems, produce insufficient steroid hormones
  • Addison’s diseaseA disorder of the adrenal glands leading to deficiency of hormones cortisol and aldosterone.
  • adenocarcinomaA malignant tumour, or cancer, that arises from glandular tissue.
  • adenoidA mass of lymphatic tissue at the back of the throat
  • adenomaA benign tumour that forms from glandular cells.
  • ADHAn abbreviation for antidiuretic hormone.
  • adhesionsAn abnormal connection between two surfaces of the body.
  • adnexal massesThis is a general term to include ovarian cysts, ectopic pregnancy and benign or malignant lumps.
  • adrenal glandOne of a pair of small, triangular shaped glands located above each kidney.
  • adrenal glandsA pair of small, triangular shaped glands located above each kidney, responsible for regulating the body’s response to stress and helping to control metabolism.
  • adrenalectomyThe surgical removal of one of the two adrenal glands. The adrenal glands sit on top of the kidneys and produce adrenaline.
  • adrenalineA hormone produced by the adrenal glands, which stimulates increases in the heart rate, breathing and metabolic rate.
  • adrenocortical tumourA very rare type of tumour in which malignant cells form in the outer layer of the adrenal gland.
  • adverse effectsUndesirable side-effects of medication.
  • aerophagyExcessive swallowing of air, which may be caused by rapid eating or drinking or by anxiety.
  • AFAn abbreviation for atrial fibrillation
  • AFPAn abbreviation for alpha-fetoprotein
  • agranulocytosis A blood disorder in which there is a sudden and dangerous fall in levels of a type of white blood cell called granulocytes.
  • AIDSAcquired immune deficiency syndrome, a deficiency of the immune system due to infection with HIV.
  • Albright's syndromeA genetic disorder affecting bones, skin pigmentation and hormone production.
  • albuminA type of chemical called a protein, formed in the liver.
  • aldosteroneA hormone produced by the adrenal glands that helps to regulate salt and water balance in the body.
  • Alexander techniqueA physical therapy technique that aims to amend everyday movement patterns and posture to improve coordination, balance and ease of movement.
  • alkaline phosphataseAn enzyme that leaks into the blood in certain diseases of liver and bone, especially metastases from cancer.
  • ALLAn abbreviation that stands for acute lymphoblastic leukaemia, a type of leukaemia that is most common in the one to five age group.
  • allergenAny substance that provokes an allergic reaction
  • allergic eczemaA red, itchy skin eruption due to an allergic reaction.
  • allergic rhinitisA runny nose (rhinitis) due to an allergic response
  • allergyVarious conditions caused by exaggerated reactions of the immune system (hypersensitivity reactions) to a variety of substances.
  • allogeneic transplantA donor transplant.
  • alopeciaLoss or absence of hair.
  • alopecia areataA patchy hair loss condition.
  • ALTAn abbreviation for alanine-amino transferase
  • alveoliThe tiny air sacs of the lungs where gas exchange takes place
  • alveolitisInflammation of the alveoli
  • Alzheimer’s diseaseA form of dementia common among older people.
  • amenorrhoeaThe absence of menstrual periods.
  • amino acidAn organic compound that is the basic building block of all proteins.
  • aminoglycosidesA type of antibiotic drug.
  • aminosalicylatesA family of drugs that reduce inflammation.
  • AMLAn abbreviation for acute myeloid leukaemia, a type of leukaemia that occurs most commonly in the over 50 age group.
  • amnesiaMemory loss.
  • amoebiasisA disease caused by a one-celled parasite.
  • amylaseAn enzyme that breaks starch down into sugar.
  • amyloidA compound similar to starch, which can build up abnormally in the tissues in a condition called amyloidosis.
  • amyloid plaqueAn aggregation of amyloid (a compound similar to starch) in the tissue of the nervous system.
  • amyloidosisA variety of conditions in which a protein called amyloid builds up in organs or tissues.
  • anaemiaA reduced level of haemoglobin, which carries oxygen in the blood. Anaemia causes tiredness, breathlessness and abnormally pale skin.
  • anaestheticA medication that reduces sensation.
  • anal fissureA small (but intensely painful) tear in the skin of the anus, usually due to passing a hard stool.
  • analgesicsAnother term for painkillers.
  • androgenA type of steroid hormone that stimulates male development. Testosterone is an androgen.
  • aneurysmAn abnormal swelling in the wall of an artery.
  • anginaA central chest pain caused by insufficient oxygen supply to the heart.
  • angiodysplasiaA condition in which blood vessels in the gastrointestinal tract become enlarged and fragile.
  • angioedemaA type of reaction caused by allergy.
  • angiogramAn X-ray image of the blood vessels following the injection of a dye to improve visibility.
  • angiographicRelating to X-ray imaging of the blood vessels following the injection of a dye to improve visibility
  • angiographyX-ray imaging of the blood vessels following the injection of a dye to improve visibility.
  • angioneurotic oedemaRecurring periods of rapid non-inflammatory swelling that affects the skin, brain, intestinal organs and mucous membranes. in severe cases respiratory swelling can lead to breathing difficulties.
  • angiopathyDisease of the blood vessels.
  • angioplastyThe mechanical widening or clearing of a narrowed or obstructed blood vessel, performed during angiography, which is used to help with visibility.
  • angiotensin converting enzyme inhibitorsA group of drugs used to treat high blood pressure and heart failure.
  • angiotensin receptor blockerOne of a group of drugs used to treat high blood pressure.
  • angiotensin receptor blockersA group of drugs used to treat high blood pressure.
  • angular cheilitisInflammation at the corner of the mouth causing splits in the skin, often due to Candida infection.
  • ankylosing spondylitisA type of chronic arthritis affecting the sacro-iliac joints (between the spine and the pelvis) and the vertebral joints of the spine
  • anorexiaA loss of appetite resulting in weight loss. Anorexia nervosa is a psychological illness in which self-starvation leads to weight loss.
  • anorexia nervosaAn eating disorder characterised by severe weight loss and altered self-image that leads sufferers to believe that they are overweight when they are in fact dangerously underweight. It most often affects teenaged girls and young women but the incidence in young men is rising.
  • anosmiaLoss of the sense of smell.
  • anovulatory cycleA menstrual cycle in which ovulation fails to occur.
  • antagonistsDrugs that are used to counter the effects of naturally occurring chemicals in the body.
  • anti-androgenic drugsHormonal medication that antagonises the actions of androgens (male hormones).
  • anti-inflammatoryAny drug that suppresses inflammation
  • anti-reflux surgerySurgery to prevent reflux, or the backflow of liquid.
  • antibioticsMedication to treat infections caused by microbes (organisms that can't be seen with the naked eye), such as bacteria.
  • antibodiesSpecial proteins in the blood that are produced in response to a specific antigen and play a key role in immunity and allergy.
  • antibodyOne of a group of special proteins in the blood that are produced in response to a specific antigen and play a key role in immunity and allergy.
  • anticholinergics A group of drugs that block nerve impulses in the parasympathetic nervous system.
  • anticoagulantA medication that prevens blood from clotting, or which reduces the likelihood of the blood to clot.
  • antigenA substance that prompts the immune system to fight infection with antibodies.
  • antigenic variabilityA change in the antigens on the surface of a microbe, which may result in it escaping detection by the immune system.
  • antihistamineA drug that blocks the action of histamine in the body; these are used to treat conditions such as hay fever.
  • antimitichondrial antibodyAn antibody that form against mitochondria, which are an important part of cells.
  • antioxidantA chemical that can neutralise damaging substances called oxygen free radicals.
  • antiphospholipid syndromeAlso known as Hughes syndrome. A type of autoimmune disease, caused by overactivity of the immune system. It is associated with thrombosis and, in women of childbearing age, recurrent miscarriage.
  • antiplatelet therapyTherapy to prevent the clustering of platelets (platelet adhesion) in the blood, so preventing the formation of clots.
  • antitussiveMedication to suppress a cough.
  • antiviralA substance that acts against viruses, for example and antiviral drug.
  • ANUGAn abbreviation for acute necrotising ulcerative gingivitis - a severe and painful gum infection also known as 'trench mouth'
  • anuriaA failure of the kidneys to produce urine.
  • anusThe external opening of the back passage, the rectum.
  • aortaThe body's main artery, which arises out of the heart and supplies blood to all other parts of the body.
  • aphasiaDifficulty in understanding and generating speech.
  • aphthous ulcerA small, painful sore in the mouth or throat, also known as a canker sore. They are very common and harmless
  • aplastic anaemiaA rare but serious type of anaemia in which the red blood cells, white blood cells and platelets in the blood are all reduced. It is caused by a failure of the bone marrow to produce stem cells.
  • apolipoproteinThe protein part of lipoproteins, compounds that function to transport lipids in the bloodstream.
  • apolipoprotein BThe main protein part of low-density lipoprotein, a compound that functions to transport lipids in the bloodstream.
  • apoptosisA natural process of programmed cell death, for example, when cells are old or damaged.
  • appendicitisInflammation of the appendix, a small tube attached to the large intestine.
  • appendix testisA small solid projection of tissue on the outer surface of the testis.
  • ARCAn abbreviation for AIDS-related complex
  • ARDSAcute Respiratory Distress Syndrome
  • areolaThe small area of darkened skin surrounding the nipple of the breast
  • arrhenoblastomaA rare type of ovarian tumour.
  • arrhythmiaAny form of disturbance to the heart's normal regular beat
  • arrhythmiaAn abnormal heart rhythm.
  • arterial insufficiencyWhen the amount of blood flowing through an artery is insufficient to meet the needs of the tissue.
  • arteriovenous fistulaAn abnormal connection between an artery and a vein.
  • arteriovenous malformationA group of veins and arteries with abnormal connections between the two.
  • arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood.
  • arthralgiaPain in the joints.
  • arthritisInflammation of one or more joints of the body.
  • arthrodesis<p>Fusion or rigidity between two bones.</p>
  • arthrofibrosisA complication following an injury or trauma to a joint where excessive scar tissue leads to painful restriction of joint motion.
  • arthropathyDisease of a joint.
  • arthroscopic debridementKeyhole surgery to the lining of a joint.
  • arthroscopyInspection through an endoscope of the interior of a joint.
  • artificial ventilationAlso known as artificial respiration, a procedure to maintain air flow into and out of the lungs. Examples include mouth-to-mouth resuscitation and the use of a ventilator.
  • ascitesThe accumulation of fluid in the peritoneal cavity, causing abdominal swelling.
  • ASDAtrial septal defect, a hole in the wall separating the two upper chambers of the heart (atria).
  • ASOantistreptolysin
  • AspergillosisA rare lung infection caused by inhaling spores of the fungus Aspergillus
  • aspirationThe withdrawal of fluid or cells from the body by suction.
  • aspiration pneumoniaInfection of the lungs owing to inhalation of a foreign body, usually food particles, through the windpipe (trachea).
  • aspiration pneumonitisInflammation of the lung due to inhalation of foreign material that does not belong in the airway, such as food, liquids or vomit
  • aspiration pneumonitisInflammation of the lung due to inhalation of foreign material that does not belong in the airway, such as food, liquids or vomit
  • aspirinOne of the most used medicines.
  • ASTaspartate-amino transferase
  • asthmaA respiratory disease featuring attacks of breathlessness and wheezing due to inflammation and narrowing of the upper airways. There is often an allergic component.
  • ataxiaClumsiness affecting balance that may be caused by damage to the cerebellum or to nerve pathways in the brainstem and spinal cord.
  • ataxiaDifficulty in the regulation of posture and the movement of limbs.
  • atheromaThe formation of fatty deposits in the arteries, which limit blood flow.
  • atheromatous plaqueFatty deposits in the walls of the arteries, seen in atherosclerosis.
  • atherosclerosisDisease leading to fatty deposits in the inner walls of the arteries, which reduce and may eventually obstruct blood flow.
  • atherosclerotic plaqueFatty plaques that form in the inner walls of arteries in atherosclerosis.
  • athralgiaPain in the joints from many possible causes.
  • atomsThe smallest units of an element.
  • atriaThe two upper chambers of the heart.
  • atrial fibrillationAbnormally fast and uneven contractions of the muscle of the atria in the heart, so that blood cannot be pumped efficiently
  • atrial fibrillationA common abnormal heart rhythm causing a rapid, irregular pulse and failure of the upper chambers of the heart (atria) to pump properly. Abbreviated to AF.
  • atrial flutterAn abnormally fast but regular heart rhythm due to disturbances in the biological electrical system of the atria of the heart. It is a type of supraventricular tachycardia
  • atrial septal defectA hole in the wall separating the two upper chambers of the heart (atria), present from birth. Abbreviated to ASD.
  • atrioventricular blockA block in the normal conduction of electrical activity between the upper and lower chambers of the heart (atria and ventricles).
  • atriumOne of the two upper chambers of the heart.
  • atrophicRelating to atrophy.
  • atrophic rhinitisRhinitis due to atrophy of the mucous membrane lining the nose, causing it to become thin, dry and crusty.
  • atrophic vaginitisInflammation of the vagina.
  • atrophyWithering or weakening of a body tissue due to disease or disuse.
  • attenuatedA microbe that has been treated so as to be less able to cause disease. Attenuated bacteria or viruses are used in many immunisations, to stimulate the body's immune system against a disease without actually causing that disease.
  • attenuationTreatment of a microbe so that it is less able to cause disease. Attenuated bacteria or viruses are used for many immunisations, to stimulate the body's immune system against a disease without actually causing that disease.
  • audiometryThe measurement of hearing.
  • auditoryRelating to the sense of hearing.
  • autoantibodyAn antibody that reacts against the body's own cells.
  • Autoantibody An antibody directed against the body's own tissues, typically produced in autoimmune disorders
  • autoantibody testA laboratory test used to help diagnose autoimmune disorders.
  • autoimmuneAny condition caused by the body’s immune response against its own tissues.
  • autoimmune screenA test that help to diagnose disorders caused by a reaction of the immune system against the body's own cells and tissues.
  • autonomicThe part of the nervous system supplying muscles such as the heart and bowels, known as involuntary muscles.
  • avascular necrosisA disease that results from the temporary or permanent loss of blood supply to the bones.
  • Avascular necrosisThe death of cells in body tissue caused by damage to blood vessels supplying the area with blood.
  • AXRAn abbreviation for abdominal x-ray.
  • ayurvedaAn ancient system of Indian medicine.
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