The following are health and medical definitions of terms that appear in the Swine Flu article.
Abate: To lessen or decrease. After a boil is lanced, the pus can drain and the pain and tenderness abate. From the French abbatre, to beat down.
Abnormal: Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer).
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. See the entire definition of Acute
Acute respiratory distress syndrome: Better known as ARDS. See: ARDS.
Adjuvant: The Latin "adjuvans" means to help, particularly to reach a goal. See the entire definition of Adjuvant
Adverse event: In pharmacology, any unexpected or dangerous reaction to a drug.
Aerosol:1. In general, a fine mist or spray which contains minute particles. 2. In medicine, a spray administered by a nebulizer and inhaled for treatment. 3. In medicine, a mist that causes disease as, for example, the hantavirus pulmonary syndrome. 4. In the environment, particles emitted into the air naturally as in volcanic eruptions and through human action such as burning fossil fuel. 5. In the environment, the pressurized gas used to propel substances out of a container.
Aerosolization: The production of an aerosol -- a fine mist or spray containing minute particles. See: Aerosol.
Affinity: In immunology, the strength of binding interaction between antigen and antibody molecules.
Airway: The path air follows to get into and out of the lungs. The mouth and nose are the normal entry and exit ports. Entering air then passes through the back of the throat (pharynx), continues through the voice box (larynx), down the trachea, and finally out the branching tubes known as bronchi.
Allergic reaction: The hypersensitive response of the immune system of an allergic individual to a substance. See the entire definition of Allergic reaction
Allergy: A misguided reaction to foreign substances by the immune system, the body system of defense against foreign invaders, particularly pathogens (the agents of infection). The allergic reaction is misguided in that these foreign substances are usually harmless. The substances that trigger allergy are called allergen. Examples include pollens, dust mite, molds, danders, and certain foods. People prone to allergies are said to be allergic or atopic. See the entire definition of Allergy
Alveoli: The plural of alveolus. The alveoli are tiny air sacs within the lungs where the exchange of oxygen and carbon dioxide takes place.
Ambulatory: Able to ambulate, to walk about, not bed-ridden or hospitalized.
Ambulatory care: Medical care including diagnosis, observation, treatment and rehabilitation that is provided on an outpatient basis. Ambulatory care is given to persons who are able to ambulate or walk about. A well-baby visit is considered ambulatory care even though the baby may not yet be walking.
Analysis: A psychology term for processes used to gain understanding of complex emotional or behavioral issues.
Anaphylaxis: Allergic reaction. In severe cases, this can include potentially deadly anaphylactic shock.
Antibody: An immunoglobulin, a specialized immune protein, produced because of the introduction of an antigen into the body, and which possesses the remarkable ability to combine with the very antigen that triggered its production. See the entire definition of Antibody
Antigen: A substance that is capable of causing the production of an antibody. See the entire definition of Antigen
Antigenic drift: A mechanism for variation by viruses that involves the accumulation of mutations within the antibody-binding sites so that the resulting viruses cannot be inhibited well by antibodies against previous strains making it easier for them to spread throughout a partially immune population. Antigenic drift occurs in both influenza A and influenza B viruses.
Antigenic shift: A sudden shift in the antigenicity of a virus resulting from the recombination of the genomes of two viral strains. Antigenic shift is seen only with influenza A viruses. It results usually from the replacement of the hemagglutinin (the viral attachment protein that also mediates the entry of the virus into the cell) with a novel subtype that has not been present in human influenzaviruses for a long time. The source of these new genes is the large reservoir of influenzaviruses in waterfowl. The consequences of the introduction of a new hemagglutinin into human viruses is usually a pandemic, or a worldwide epidemic.
Antiviral: An agent that kills a virus or that suppresses its ability to replicate and, hence, inhibits its capability to multiply and reproduce. See the entire definition of Antiviral
Antiviral agent: An agent that kills viruses or suppresses their replication and, hence, inhibits their capability to multiply and reproduce. See the entire definition of Antiviral agent
ARDS: Acute Respiratory Distress Syndrome. A fulminant lung condition in which trauma to the lungs leads to inflammation of the lungs, accumulation of fluid in the alveolar air sacs, low blood oxygen, and respiratory distress. See the entire definition of ARDS
The presence of a substance and the amount of that substance. Thus, an assay may be done for example to determine the level of thyroid hormones in the blood of a person suspected of being hypothyroid (or hyperthyroid).
The biological or pharmacological potency of a drug. For example, an assay may be done of a vaccine to determine its potency.
Asthma: A common disorder in which chronic inflammation of the bronchial tubes (bronchi) makes them swell, narrowing the airways. Asthma involves only the bronchial tubes and does not affect the air sacs (alveoli) or the lung tissue (the parenchyma of the lung) itself. See the entire definition of Asthma
Asymptomatic: Without symptoms. For example, an asymptomatic infection is an infection with no symptoms.
Attenuated: Weakened, diluted, thinned, reduced, weakened, diminished. See the entire definition of Attenuated
Attenuated virus: To attenuate is to weaken or to make (or become) thin. The word derives from a combination of the Latin prefix "ad-," meaning "to" or "toward," and "tenuis," meaning "thin." See the entire definition of Attenuated virus
Autopsy: A postmortem examination. Also called a necropsy. See the entire definition of Autopsy
Avian influenza: Also called fowl plague, avian flu, and bird flu. A highly contagious viral disease with up to 100% mortality in domestic fowl. Caused by influenza A virus subtypes H5 and H7. All types of birds are susceptible to the virus but outbreaks occur most often in chickens and turkeys. The infection may be brought by migratory wild birds which can carry the virus but show no signs of disease. Humans are only rarely affected. See the entire definition of Avian influenza
B virus: An infectious agent commonly found among macaque monkeys, including rhesus macaques, pig-tailed macaques, and cynomolgus monkeys. Monkeys infected with this virus usually have no or mild symptoms. In humans, however, B virus infection can result in a fatal encephalomyelitis. B virus disease in humans is extremely rare, but often fatal -- an estimated 80% of untreated patients die of complications associated with the infection. See the entire definition of B virus
Bacteria: Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life). See the entire definition of Bacteria
Bacterial: Of or pertaining to bacteria. For example, a bacterial lung infection.
Baseline:1. Information gathered at the beginning of a study from which variations found in the study are measured. 2. A known value or quantity with which an unknown is compared when measured or assessed. 3. The initial time point in a clinical trial, just before a participant starts to receive the experimental treatment which is being tested. At this reference point, measurable values such as CD4 count are recorded. Safety and efficacy of a drug are often determined by monitoring changes from the baseline values.
Biochemical: Relating to biochemistry, the application of the tools and concepts of chemistry to living systems. See the entire definition of Biochemical
Bioterrorism: Terrorism using biologic agents that are harmful to humans. Biological diseases and the agents that might be used for terrorism have been listed by the US Centers for Disease Control and Prevention (CDC). These agents include viruses, bacteria, rickettsiae (microorganisms that have traits common to both bacterial and viruses), fungi, and biological toxins. The biological disease agents are classified into three categories, according to the degree of danger each agent is felt to pose. See the entire definition of Bioterrorism
Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension".
Body mass index: A key index for relating a person's body weight to their height. The body mass index (BMI) is a person's weight in kilograms (kg) divided by their height in meters (m) squared. See the entire definition of Body mass index
Bowel: Another name for the intestine. The small bowel and the large bowel are the small intestine and large intestine, respectively. See the entire definition of Bowel
Breathing: The process of respiration, during which air is inhaled into the lungs through the mouth or nose due to muscle contraction, and then exhaled due to muscle relaxation.
Bridge: A set of one or more false teeth supported by a metal framework, used to replace one or more missing teeth. See the entire definition of Bridge
Bronchiolitis: Inflammation of the bronchioles, the airways that extend beyond the bronchi and terminate in the alveoli. Bronchiolitis is due to viral infections such as parainfluenza, influenza, adenovirus and, especially, respiratory syncytial virus (RSV). See the entire definition of Bronchiolitis
Bronchoscopy: A procedure that permits the doctor to see the breathing passages through a lighted tube.
Bypass: An operation in which a surgeon creates a new tubular pathway for the movement of fluids and/or other substances in the body.
Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread). See the entire definition of Cancer
Cardiac: Having to do with the heart.
Cardiovascular: The circulatory system comprising the heart and blood vessels which carries nutrients and oxygen to the tissues of the body and removes carbon dioxide and other wastes from them. See the entire definition of Cardiovascular
CDC: The Centers for Disease Control and Prevention, the US agency charged with tracking and investigating public health trends. The stated mission of the CDC is "To promote health and quality of life by preventing and controlling disease, injury, and disability." The CDC is a part of the U.S. Public Health Services (PHS) under the Department of Health and Human Services (HHS). See the entire definition of CDC
Cell: The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane. See the entire definition of Cell
Cell fusion: The melding of two or more cells into one cell called a heterokaryon. A heterokaryon may reproduce itself for at least several generations. Cell fusion provides a method for assigning specific genes to specific chromosomes. See the entire definition of Cell fusion
Centers for Disease Control and Prevention: The US agency charged with tracking and investigating public health trends. The stated mission of the Centers for Disease Control and Prevention, commonly called the CDC, is "To promote health and quality of life by preventing and controlling disease, injury, and disability." See the entire definition of Centers for Disease Control and Prevention
Cerebral: Pertaining to the brain, the cerebrum or the intellect. See the entire definition of Cerebral
Cerebral palsy: An abnormality of motor function (the ability to move and control movements) that is acquired at an early age, usually less than a year of age, and is due to a brain lesion that is non-progressive. Cerebral palsy (CP) is frequently the result of abnormalities that occur in utero, while the fetus is developing inside the mother's womb. Such abnormalities may include accidents of brain development, genetic disorders, stroke due to abnormal blood vessels or blood clots, or infection of the brain. In rare instances, obstetrical accidents during particularly difficult deliveries can cause brain damage and result in CP. CP may be divided into spastic, choreoathetoid, and hypotonic (flaccid) CP. In spastic CP, there is an abnormality of muscle tone in which one or more extremities (arm or leg) is held in a rigid posture. Choreoathetoid CP is associated with abnormal, uncontrollable, writhing movements of the arms and/or legs. The child with hypotonic CP appears floppy -- like a rag doll. Treatment may include casting and braces to prevent further loss of limb function, speech therapy, physical therapy, occupational therapy, the use of augmentative communication devices, and the use of medications of botox injections to treat spasticity.
Chemoprophylaxis: The use of a chemical agent to prevent the development of a disease. See: Chemoprevention.
Chest: The area of the body located between the neck and the abdomen. The chest contains the lungs, the heart and part of the aorta. The walls of the chest are supported by the dorsal vertebrae, the ribs, and the sternum. See the entire definition of Chest
Chest pain: There are many causes of chest pain. One is angina which results from inadequate oxygen supply to the heart muscle. Angina can be caused by coronary artery disease or spasm of the coronary arteries. Chest pain can also be due to a heart attack (coronary occlusion) and other important diseases such as, for example, dissection of the aorta and a pulmonary embolism. Do not try to ignore chest pain and "work (or play) though it." Chest pain is a warning to seek medical attention.
Chills: feelings of coldness accompanied by shivering. Chills may develop after exposure to a cold environment or may accompany a fever.
Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time. See the entire definition of Chronic
Chronic disease: A disease that persists for a long time. A chronic disease is one lasting 3 months or more, by the definition of the U.S. National Center for Health Statistics. Chronic diseases generally cannot be prevented by vaccines or cured by medication, nor do they just disappear. Eighty-eight percent of Americans over 65 years of age have at least one chronic health condition (as of 1998). Health damaging behaviors - particularly tobacco use, lack of physical activity, and poor eating habits - are major contributors to the leading chronic diseases. See the entire definition of Chronic disease
Clinical trials: Trials to evaluate the effectiveness and safety of medications or medical devices by monitoring their effects on large groups of people. See the entire definition of Clinical trials
Cluster: In epidemiology, an aggregation of cases of a disease or another health-related condition, such as a cancer or birth defect, closely grouped in time and place. The number of cases in the cluster may or may not exceed the expected number. This is determined by cluster analysis, a set of statistical methods used to analyze clusters.
Cohort: In a clinical study, a well-defined group of subjects or patients who have had a common experience or exposure and are then followed up for the incidence of new diseases or events, as in a cohort study. See the entire definition of Cohort
Collateral: In anatomy, a collateral is a subordinate or accessory part. A collateral is also a side branch, as of a blood vessel or nerve. See the entire definition of Collateral
Complication: In medicine, an additional problem that arises following a procedure, treatment or illness and is secondary to it. A complication complicates the situation.
Congestion: An abnormal or excessive accumulation of a body fluid. The term is used broadly in medicine. Examples include nasal congestion (excess mucus and secretions in the air passages of the nose) seen with a common cold and congestion of blood in the lower extremities seen with some types of heart failure.
Conjunctivitis: Inflammation of the conjunctiva, the membrane on the inner part of the eyelids and the membrane covering the white of the eye. The conjunctival membranes react to a wide range of bacteria, viruses, allergy-provoking agents, irritants and toxic agents. Viral and bacterial forms of conjunctivitis are common in childhood. Conjunctivitis is also called pinkeye and red eye. See the entire definition of Conjunctivitis
Contraindication: A condition which makes a particular treatment or procedure inadvisable. A contraindication may be absolute or relative.
An absolute contraindication is a situation which makes a particular treatment or procedure absolutely inadvisable. In a baby, for example, aspirin is absolutely contraindicated because of the danger that aspirin will cause Reye syndrome.
A relative contraindication is a condition which makes a particular treatment or procedure somewhat inadvisable but does not rule it out. For example, X-rays in pregnancy are relatively contraindicated (because of concern for the developing fetus) unless the X-rays are absolutely necessary.
Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.
Coronavirus: One of a group of RNA viruses, so named because they look like a corona or halo when viewed under the electron microscope. The corona or halo is due to an array of surface projections on the viral envelope. See the entire definition of Coronavirus
Cough: A rapid expulsion of air from the lungs typically in order to clear the lung airways of fluids, mucus, or material. Also called tussis.
Critical care: Intensive care. The specialized care of patients whose conditions are life-threatening and who require comprehensive care and constant monitoring, usually in intensive care units.
Crohn's disease: A chronic inflammatory disease, primarily involving the small and large intestine, but which can affect other parts of the digestive system as well. It is named for Burrill Crohn, the American gastroenterologist who first described the disease in 1932. See the entire definition of Crohn's disease
Department of Health and Human Services : The United States government's principal agency for "protecting the health of all Americans and providing essential human services, especially for those who are least able to help themselves." Also known as DHHS and HHS. See the entire definition of Department of Health and Human Services
Diabetes: Refers to diabetes mellitus or, less often, to diabetes insipidus. Diabetes mellitus and diabetes insipidus share the name "diabetes" because they are both conditions characterized by excessive urination (polyuria). See the entire definition of Diabetes
Diagnosis:1 The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV. See the entire definition of Diagnosis
Diarrhea: A familiar phenomenon with unusually frequent or unusually liquid bowel movements, excessive watery evacuations of fecal material. The opposite of constipation. The word "diarrhea" with its odd spelling is a near steal from the Greek "diarrhoia" meaning "a flowing through." Plato and Aristotle may have had diarrhoia while today we have diarrhea. There are myriad infectious and noninfectious causes of diarrhea. See the entire definition of Diarrhea
Donor: The giver of a tissue or organ, for example, of blood or a kidney.
Double-blind: Term used to described a study in which both the investigator or the participant are blind to (unaware of) the nature of the treatment the participant is receiving. Double-blind trials are thought to produce objective results, since the expectations of the researcher and the participant about the experimental treatment such as a drug do not affect the outcome. Also called double-masked. See also: Double-blinded study.
Dyspnea: Difficult or labored breathing; shortness of breath. See the entire definition of Dyspnea
Ear: The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain. See the entire definition of Ear
Elbow: The juncture of the long bones in the middle portion of the arm. The bone of the upper arm (humerus) meets both the ulna (the inner bone of the forearm) and radius (the outer bone of the forearm) to form a hinge joint at the elbow. The radius and ulna also meet one another in the elbow to permit a small amount of rotation of the forearm. The elbow therefore functions to move the arm like a hinge (forward and backward) and in rotation (outward and inward). The biceps muscle is the major muscle that flexes the elbow hinge, and the triceps muscle is the major muscle that extends it. The primary stability of the elbow is provided by the ulnar collateral ligament, located on the medial (inner) side of the elbow. The outer bony prominence of the elbow is the lateral epicondyle, a part of the humerus bone. Tendons attached to this area can be injured, causing inflammation or tendonitis (lateral epicondylitis, or tennis elbow). The inner portion of the elbow is a bony prominence called the medial epicondyle of the humerus. Additional tendons from muscles attach here and can be injured, likewise causing inflammation or tendonitis (medial epicondylitis, or golfer's elbow). See also: Elbow bursitis; Elbow pain; Nursemaid's elbow.
Elective: In medicine, something chosen (elected). An elective procedure is one that is chosen (elected) by the patient or physician that is advantageous to the patient but is not urgent. See the entire definition of Elective
Elective surgery: Surgery that is subject to choice (election). The choice may be made by the patient or doctor. See the entire definition of Elective surgery
Emboli: Something that travels through the bloodstream, lodges in a blood vessel and blocks it. Examples of emboli are a detached blood clot, a clump of bacteria, and foreign material such as air. See the entire definition of Emboli
Embryo: The organism in the early stages of growth and differentiation from fertilization to, in humans, the beginning of the third month of pregnancy. After that point in time, it is termed a fetus.
Emergency department: The department of a hospital responsible for the provision of medical and surgical care to patients arriving at the hospital in need of immediate care. Emergency department personnel may also respond to certain situations within the hospital such cardiac arrests. See the entire definition of Emergency department
Enzyme: A protein (or protein-based molecule) that speeds up a chemical reaction in a living organism. An enzyme acts as catalyst for specific chemical reactions, converting a specific set of reactants (called substrates) into specific products. Without enzymes, life as we know it would not exist. See the entire definition of Enzyme
Epidemic: The occurrence of more cases of a disease than would be expected in a community or region during a given time period. A sudden severe outbreak of a disease such as SARS. From the Greek "epi-", "upon" + "demos", "people or population" = "epidemos" = "upon the population." See also: Endemic; Pandemic.
Epithelial: Relating to the epithelium, the outside layer of cells that covers all the free, open surfaces of the body including the skin, and mucous membranes that communicate with the outside of the body.
Epitope: A single antigenic site on a protein against which an antibody reacts.
Essential:1. Something that cannot be done without. 2. Required in the diet, because the body cannot make it. As in an essential amino acid or an essential fatty acid. 3. Idiopathic. As in essential hypertension. "Essential" is a hallowed term meaning "We don't know the cause."
Exacerbation: A worsening. In medicine, exacerbation may refer to an increase in the severity of a disease or its signs and symptoms. For example, exacerbation of asthma is one of the serious effects of air pollution..
Extracorporeal: Outside the body, in the anatomic sense. As in extracorporeal circulation, extracorporeal dialysis, and extracorporeal shock wave lithotripsy. From extra- + corpus, meaning body.
Extracorporeal membrane oxygenation: (ECMO) A life support system that circulates the blood through an oxygenating system. ECMO is like a heart-lung machine that takes over the work of the heart and lungs during open heart surgery. ECMO may be used, for example, to treat ARDS (acute respiratory distress syndrome), lethal smoke inhalation injury, or irreversible heart failure. As a general rule, ECMO is only used for limited time because of the high risks of bleeding, clotting, infection and organ failure.
Family practice: The medical specialty which provides continuing and comprehensive health care for the individual and family. It is the specialty in breadth which integrates the biological, clinical, and behavioral sciences. The scope of family practice encompasses all ages, both sexes, each organ system, and every disease entity. (From the American Academy of Family Physicians)
Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist. See the entire definition of Fatigue
FDA: The Food and Drug Administration, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services. See the entire definition of FDA
Febrile: Feverish.
Feces: The medical and scientific term for the "excrement discharged from the intestines." See the entire definition of Feces
Fetus: The unborn offspring from the end of the 8th week after conception (when the major structures have formed) until birth. Up until the eighth week, the developing offspring is called an embryo.
Fever: Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). See the entire definition of Fever
Flu: Short for influenza. The flu is caused by viruses that infect the respiratory tract which are divided into three types, designated A, B, and C. Most people who get the flu recover completely in 1 to 2 weeks, but some people develop serious and potentially life-threatening medical complications, such as pneumonia. Much of the illness and death caused by influenza can be prevented by annual influenza vaccination.
Flu shot: The flu (influenza) vaccine is recommended annually (each year) for persons at high risk for serious complications from influenza virus infection. See the entire definition of Flu shot
Flu vaccine: The flu vaccination (influenza) is recommended for persons at high risk for serious complications from influenza virus infection. See the entire definition of Flu vaccine
Food and Drug Administration: The FDA, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services. See the entire definition of Food and Drug Administration
Formalin: A 37% aqueous (water) solution of formaldehyde, a pungent gas, with the chemical formula HCHO, used as an antiseptic, disinfectant, and especially today as a fixative for histology (the study of tissues under the microscope).
Gastrointestinal: Adjective referring collectively to the stomach and small and large intestines. See the entire definition of Gastrointestinal
Genes: The basic biological units of heredity. Segments of deoxyribonucleic acid (DNA) needed to contribute to a function. See the entire definition of Genes
Genetic: Having to do with genes and genetic information.
Genetic code: The instructions in a gene that tell the cell how to make a specific protein. A, T, G, and C are the "letters" of the DNA code. They stand for the chemicals adenine, thymine, guanine, and cytosine, respectively, that make up the nucleotide bases of DNA. Each gene's code combines the four chemicals in various ways to spell out 3-letter "words" that specify which amino acid is needed at every step in making a protein. See the entire definition of Genetic code
Genetics: The scientific study of heredity. Genetics pertains to humans and all other organisms. So, for example, there is human genetics, mouse genetics, fruitfly genetics, etc. See the entire definition of Genetics
Genome: All of the genetic information, the entire genetic complement, all of the hereditary material possessed by an organism. See the entire definition of Genome
Genomic: Pertaining to the genome, all of the genetic information possessed by any organism. See the entire definition of Genomic
Genomics: The study of genes and their function. Genomics aims to understand the structure of the genome, including the mapping genes and sequencing the DNA. Genomics examines the molecular mechanisms and the interplay of genetic and environmental factors in disease. See the entire definition of Genomics
Gynecology: The branch of medicine particularly concerned with the health of the female organs of reproduction and diseases thereof. See the entire definition of Gynecology
Headache: A pain in the head with the pain being above the eyes or the ears, behind the head (occipital), or in the back of the upper neck. Headache, like chest pain or back ache, has many causes. See the entire definition of Headache
Health and Human Services : The United States government's principal agency for "protecting the health of all Americans and providing essential human services, especially for those who are least able to help themselves." Also known as DHHS and HHS. See the entire definition of Health and Human Services
Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest. See the entire definition of Heart
Hemorrhagic: Pertaining to bleeding or the abnormal flow of blood. See the entire definition of Hemorrhagic
HEPA: Acronym that stands for High-Efficiency Particulate Air and for High-Efficiency Particulate Arrestor. See the entire definition of HEPA
HHS: Acronym for the U.S. Department of Health and Human Services. Also known as DHHS. See the entire definition of HHS
HIV: Acronym for the Human Immunodeficiency Virus, the cause of AIDS (acquired immunodeficiency syndrome). HIV has also been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus. No matter what name is applied, it is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme. Using the reverse transcriptase, the virus uses its RNA as a template for making complementary DNA which can integrate into the DNA of the host organism). See the entire definition of HIV
Hybrid: The word "hybrid" has a number of different biomedical meanings. See the entire definition of Hybrid
Hygiene: The science of preventive medicine and the preservation of health. From the name of Hygeia, the daughter of Asklepios, the Greek god of medicine (whose staff with entwined snake is the symbol of medicine). Asklepios (known to the Romans as Aesculapius) had a number of children including not only Hygeia but also Panaceia, the patroness of clinical medicine. Hygeia also followed her father into medicine. As the patroness of health, Hygeia was charged with providing a healthy environment to prevent illness. In Greek, "hygieia" means health.
Hypertension: High blood pressure, defined as a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90. See the entire definition of Hypertension
Hypoxemia: abnormally low levels of oxygen in the blood. Hypoxemia may be mild to severe and leads to shortness of breath. Low blood oxygen can result from a variety of conditions that affect either the ability of the heart to pump blood to the lungs to receive oxygen or the function of the lungs themselves. Breathing at high altitudes can also cause hypoxemia. The level of oxygen in the blood can be measured by a test performed on a sample of arterial blood (referred to as an arterial blood gas measurement) or by an instrument known as a pulse oximeter , which is clipped onto the finger.
ICU: Intensive Care Unit.
Immune: Protected against infection. The Latin immunis means free, exempt.
Immune response: Any reaction by the immune system.
Immune system: A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders. See the entire definition of Immune system
Immunity: The condition of being immune. Immunity can be innate (for example, humans are innately immune to canine distemper) or conferred by a previous infection or immunization.
Immunization: Vaccination. Immunizations work by stimulating the immune system, the natural disease-fighting system of the body. The healthy immune system is able to recognize invading bacteria and viruses and produce substances (antibodies) to destroy or disable them. Immunizations prepare the immune system to ward off a disease. To immunize against viral diseases, the virus used in the vaccine has been weakened or killed. To immunize against bacterial diseases, it is generally possible to use only a small portion of the dead bacteria to stimulate the formation of antibodies against the whole bacteria. In addition to the initial immunization process, it has been found that the effectiveness of immunizations can be improved by periodic repeat injections or "boosters." Also see Immunizations (in the plural) and Immunization of a specific type (such Immunization, Polio).
Immunocompromised: Having an immune system that has been impaired by disease or treatment.
Immunology: The study of all aspects of the immune system including its structure and function, disorders of the immune system, blood banking, immunization and organ transplantation.
Immunosuppressant: An agent that can suppress or prevent the immune response. Immunosuppressants are used to prevent rejection of a transplanted organ and to treat autoimmune diseases such as psoriasis, rheumatoid arthritis, and Crohn's disease. Some treatments for cancer act as immunosuppressants. Also called an immunodepressant.
Immunosuppression: Suppression of the immune system. Immunosuppression may result from certain diseases such as AIDS or lymphoma or from certain drugs such as some of those used to treat cancer. Immunosuppression may also be deliberately induced with drugs, as in preparation for bone marrow or other organ transplantation to prevent the rejection of the transplant.
In vitro: Literally in glass, as in a test tube. A test that is performed in vitro is one that is done in glass or plastic vessels in the laboratory. See the entire definition of In vitro
In vivo: In the living organism, as opposed to in vitro (in the laboratory).
Incidence: The frequency with which something, such as a disease, appears in a particular population or area. In disease epidemiology, the incidence is the number of newly diagnosed cases during a specific time period. The incidence is distinct from the prevalence which refers to the number of cases alive on a certain date.
Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated.
Indication:1. In medicine, a condition which makes a particular treatment or procedure advisable. CML (chronic myeloid leukemia) is an indication for the use of Gleevec (imatinib mesylate). 2. A sign or a circumstance which points to or shows the cause, pathology, treatment, or outcome of an attack of disease. The presence of the Philadelphia chromosome in peripheral blood cells is an indication of a relapse in CML.
Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person. See the entire definition of Infection
Infectivity: The proportion of persons exposed to an infectious agent who become infected by it.
Inflammation: A basic way in which the body reacts to infection, irritation or other injury, the key feature being redness, warmth, swelling and pain. Inflammation is now recognized as a type of nonspecific immune response. See the entire definition of Inflammation
Influenza: The flu is caused by viruses that infect the respiratory tract which are divided into three types, designated A, B, and C. Most people who get the flu recover completely in 1 to 2 weeks, but some people develop serious and potentially life-threatening medical complications, such as pneumonia. Much of the illness and death caused by influenza can be prevented by annual influenza vaccination.
Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury. The injury may be accidental or deliberate, as with a needlestick injury. The term "injury" may be synonymous (depending on the context) with a wound or with trauma.
Interferon: A naturally occurring substance that interferes with the ability of viruses to reproduce. Interferon also boosts the immune system. See the entire definition of Interferon
Intracellular: Within a cell. In contrast to extracellular, meaning outside a cell.
Intubation: The process of putting a tube into a hollow organ or passageway, often into the airway. The opposite of intubation is extubation.
JAMA: The Journal of the American Medical Association. JAMA began publication in 1883. It now bills itself as "the world's best-read medical journal". However one defines "best-read", JAMA clearly ranks as one of the two leading general medical journals published in the United States. (The other is the New England Journal of Medicine.) See the entire definition of JAMA
Jaundice: Yellow staining of the skin and sclerae (the whites of the eyes) by abnormally high blood levels of the bile pigment bilirubin. The yellowing extends to other tissues and body fluids. Jaundice was once called the "morbus regius" (the regal disease) in the belief that only the touch of a king could cure it. See the entire definition of Jaundice
Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint. See the entire definition of Joint
Journal of the American Medical Association: JAMA, which began publication in 1883, now bills itself as "the world's best-read medical journal". However one defines "best-read", JAMA clearly ranks as one of the two leading general medical journals published in the United States. The other is the New England Journal of Medicine. See the entire definition of Journal of the American Medical Association
Labor: Childbirth, the aptly-named experience of delivering the baby and placenta from the uterus to the vagina to the outside world. There are two stages of labor. During the first stage (called the stage of dilatation), the cervix dilates fully to a diameter of about 10 cm. In the second stage (called the stage of expulsion), the baby moves out through the cervix and vagina to be born. See the entire definition of Labor
Laboratory: A place for doing tests and research procedures and preparing chemicals, etc. Although "laboratory" looks very like the Latin "laboratorium" (a place to labor, a work place), the word "laboratory" came from the Latin "elaborare" (to work out, as a problem, and with great pains), as evidenced by the Old English spelling "elaboratory" designating "a place where learned effort was applied to the solution of scientific problems."
Lancet: A small pointed knife; a surgical instrument with a short, wide, sharp-pointed, two-edged blade; a little knife with a small point. Lancets are used today to prick the skin (a finger, foot, ear lobe, etc.) to obtain a small quantity of capillary blood for testing. See the entire definition of Lancet
Laser: A powerful beam of light that can produce intense heat when focused at close range. Lasers are used in medicine in microsurgery, cauterization, for diagnostic purposes, etc. For example, lasers are employed in microsurgery to cut tissue and remove tissue. See the entire definition of Laser
Lethal: Deadly, fatal, capable of causing death, death-dealing. The word "lethal" comes from the Latin "letum" meaning "death or destruction."
Ligand: A molecule that binds to another. Often, a soluble molecule such as a hormone or neurotransmitter that binds to a receptor. See the entire definition of Ligand
Lips: Aside from the lips of the mouth, there are two pairs of lips at the entrance to the vagina. They are the labia majora (the larger outside pair) and the labia minora (the smaller inside pair). Together they form part of the vulva (the female external genitalia).
Low blood pressure: Any blood pressure that is below the normal expected for an individual in a given environment. Low blood pressure is also referred to as hypotension. See the entire definition of Low blood pressure
Lungs: The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.
Mechanical ventilation: Use of a machine called a ventilator or respirator to improve the exchange of air between the lungs and the atmosphere.
Median: The middle. Like the median strip in a highway.
Medical device:1. Broadly, any physical item used in medical treatment, from a cardiac pacemaker to a wheelchair. 2.In insurance terms, usually synonymous an assistive device, although it may include items more frequently thought of as medical supplies, such as dressings needed for wound care at home or syringes for self-administration of insulin. See the entire definition of Medical device
Membrane: A very thin layer of tissue that covers a surface.
Molecular biology: The study of biology on a molecular level including the structure, function, and makeup of biologically important molecules such as DNA, RNA, and proteins. The field of molecular biology involves many other areas of biology such as biochemistry and genetics.
Monoclonal: Pertaining to a single clone of cells, a single cell and the progeny of that cell. As opposed to polyclonal. See the entire definition of Monoclonal
Mortality: A fatal outcome or, in one word, death. The word "mortality" is derived from "mortal" which came from the Latin "mors" (death). The opposite of mortality is, of course, immortality. Mortality is also quite distinct from morbidity (illness). See the entire definition of Mortality
Mortality rate: A death rate. There are a number of different types of mortality rates as, for examples, the following:
The fetal mortality rate: The ratio of fetal deaths to the sum of the births (the live births + the fetal deaths) in that year.
The infant mortality rate: The number of children dying under a year of age divided by the number of live births that year.
The maternal mortality rate: The number of maternal deaths related to childbearing divided by the number of live births (or by the number of live births + fetal deaths) in that year.
Mouth:1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.
Mucus: A thick slippery fluid produced by the membranes lining certain organs such as the nose, mouth, throat, and vagina. Mucus is the Latin word for "a semifluid, slimy discharge from the nose." Note that mucus is a noun while the adjective is mucous.
Multiple sclerosis: Abbreviated MS. A disease of the central nervous system (CNS) marked by numbness, weakness, loss of muscle coordination, and problems with vision, speech, and bladder control. MS is an autoimmune disease in which the body's immune system attacks myelin, a key substance that serves as a nerve insulator and helps in the transmission of nerve signals. The progress, severity and specific symptoms in MS are unpredictable. One never knows when attacks will occur, how long they will last, or how severe they will be. Most people with MS are between the ages of 20 and 40 at the time of diagnosis. The term "multiple" refers to the multiple places in the CNS that are affected and to the multiple relapses and remissions characteristic of MS. See the entire definition of Multiple sclerosis
Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."
Muscular: Having to do with the muscles. Also, endowed with above average muscle development. Muscular system refers to all of the muscles of the body collectively.
Muscular dystrophy: One of a group of genetic diseases characterized by progressive weakness and degeneration of the skeletal or voluntary muscles which control movement. The muscles of the heart and some other involuntary muscles are also affected in some forms of muscular dystrophy, and a few forms involve other organs as well. See the entire definition of Muscular dystrophy
Mutant: An individual with a mutant (changed) gene.
Mutation: A permanent change, a structural alteration, in the DNA or RNA. In humans and many other organisms, mutations occur in DNA. However, in retroviruses like HIV, mutations occur in RNA which is the genetic material of retroviruses. See the entire definition of Mutation
Myalgia: Pain in a muscle; or pain in multiple muscles. Myalgia means muscle pain. There are many specific causes of various types of myalgia. Myalgia can be temporary or chronic. Myalgia can be a result of a mild conditions, such as a virus infection, or from a more serious illness. Examples include epidemic myalgia and polymyalgia rheumatica. See the entire definition of Myalgia
Nasal: Having to do with the nose. Nasal drops are intended for the nose, not (for example) the eyes. The word "nasal" came from the Latin "nasus" meaning the nose or snout.
National Academy of Sciences: One of the National Academies. Created in 1863 by a congressional charter approved by President Abraham Lincoln at the height of the Civil War.
Nausea:Nausea, is the urge to vomit. It can be brought by many causes including, systemic illnesses, such as influenza, medications, pain, and inner ear disease. When nausea and/or vomiting are persistent, or when they are accompanied by other severe symptoms such as abdominal pain, jaundice, fever, or bleeding, a physician should be consulted.
Neurological: Having to do with the nerves or the nervous system.
Neuromuscular: Pertaining to both nerves and muscles, as in neuromuscular blockade by an anesthetic agent, the neuromuscular junction (the meeting place of a nerve and a muscle fiber), and neuromuscular transmission (the transfer of "information" from the nerve to the muscle).
New England Journal of Medicine: Despite its regional name, The New England Journal of Medicine (NEJM) is far from provincial. It is an eminent weekly national and international general medical journal, devoted to no single specialty, but to all of medicine. The Journal is published by the Massachusetts Medical Society and is closely associated with the medical schools (Boston University, Harvard and Tufts) in the Boston area. See the entire definition of New England Journal of Medicine
NIH: The National Institutes of Health. The NIH is an important U.S. health agency. It is devoted to medical research. Administratively under the Department of Health and Human Services (HHS), the NIH consists of 20-some separate Institutes and Centers. NIH's program activities are represented by these Institutes and Centers. See the entire definition of NIH
NIOSH: The National Institute for Occupational Safety and Health, a US Federal agency responsible for conducting research and making recommendations for the prevention of work-related disease and injury. See the entire definition of NIOSH
Nose: The external midline projection from the face. See the entire definition of Nose
Nostril: One of the openings in the nose that allows air to flow in and out of the nasal cavities. The word nostril comes from the Old English nosu, nose + thyrel, hole = the nose hole.
Novel H1N1 influenza: A virus responsible for a flupandemic in 2009 that was originally referred to as "swine flu" because many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs in North America. However, the virus is actually a novel influenza A (H1N1) virus. This virus first caused illness in Mexico and the United States in March and April, 2009 that spread to pandemic status over the following months. H1N1 flu is spread from person to person, unlike typical swine flu, although it is not clear how easily the virus is able to spread among people. As of August 2009, a vaccine is under development for the novel H1N1 flu virus.
OB/GYN: A commonly used abbreviation. OB is short for obstetrics or for an obstetrician, a physician who delivers babies. GYN is short for gynecology or for a gynecologist, a physician who specializes in treating diseases of the female reproductive organs. The word "gynecology" comes from the Greek gyno, gynaikos meaning woman + logia meaning study, so gynecology literally is the study of women. These days gynecology is focused largely on disorders of the female reproductive organs. An obstetrician/gynecologist (OB/GYN) is therefore a physician who both delivers babies and treats diseases of the female reproductive organs.
Obese: Well above ones normal weight. A person has traditionally been considered to be obese if they are more than 20 percent over their ideal weight. That ideal weight must take into account the person's height, age, sex, and build. See the entire definition of Obese
Obesity: The state of being well above one's normal weight. See the entire definition of Obesity
Objective: In a microscope, the objective (also called the objective lens) is the lens nearest to the object being examined whereas the lens closest to the eye is termed the ocular (the eyepiece). See the entire definition of Objective
Obstetrics: The art and science of managing pregnancy, labor and the puerperium (the time after delivery).
Occupational Safety and Health Administration: OSHA, an agency of the US government (under the Department of Labor) with the responsibility of ensuring safety at work and a healthful work environment. See the entire definition of Occupational Safety and Health Administration
Onset: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis. There is always an onset to a disease but never to the return to good health. The default setting is good health. See the entire definition of Onset
Organ: A relatively independent part of the body that carries out one or more special functions. The organs of the human body include the eye, ear, heart, lungs, and liver.
OSHA: The Occupational Safety and Health Administration, an agency of the US government under the Department of Labor with the responsibility of ensuring safety at work and a healthful work environment. See the entire definition of OSHA
Ovary: The female gonad, the ovary is one of a pair of reproductive glands in women. They are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries produce eggs (ova) and female hormones. During each monthly menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a fallopian tube to the uterus. The ovaries are the main source of female hormones, which control the development of female body characteristics, such as the breasts, body shape, and body hair. They also regulate the menstrual cycle and pregnancy.
Oxygen: A colorless, odorless and tasteless gas that makes up about 20% of the air we breathe (and at least half the weight of the entire solid crust of the earth) and which combines with most of the other elements to form oxides. Oxygen is essential to human, animal and plant life. See the entire definition of Oxygen
Oxygenation: The addition of oxygen to any system, including the human body. Oxygenation may also refer to the process of treating a patient with oxygen, or of combining a medication or other substance with oxygen. See the entire definition of Oxygenation
Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia. Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors. See the entire definition of Pain
Palsy: Paralysis, generally partial, whereby a local body area is incapable of voluntary movement (motor function). For example, Bell's palsy is localized paralysis of the muscles on one side of the face. The word "palsy" is a corruption (and contracture) of the French word "paralysie" which means "paralysis."
Pandemic: An epidemic (a sudden outbreak) that becomes very widespread and affects a whole region, a continent, or the world. See the entire definition of Pandemic
Panic: A sudden strong feeling of fear that prevents reasonable thought or action. See the entire definition of Panic
Paralysis: Loss of voluntary movement (motor function). Paralysis that affects only one muscle or limb is partial paralysis, also known as palsy; paralysis of all muscles is total paralysis, as may occur in cases of botulism.
Pathogen: An agent of disease. A disease producer. The term pathogen most commonly is used to refer to infectious organisms. These include bacteria (such as staph), viruses (such as HIV), and fungi (such as yeast). Less commonly, pathogen refers to a noninfectious agent of disease such as a chemical. See the entire definition of Pathogen
Pathologic:1. Indicative of or caused by disease, as in a pathologic fracture, pathologic tissue, or pathologic process. 2. Pertaining to pathology, the branch of medicine that studies disease and especially the essential nature of disease.
Pathology: The study of disease. Pathology has been defined as "that branch of medicine which treats of the essential nature of disease." The word "pathology" comes from the Greek words "pathos" meaning "disease" and "logos" meaning "a treatise" = a treatise of disease. The word "pathology" is sometimes misused to mean disease as, for example, "he didn't find any pathology" (meaning he found no evidence of disease). A medical doctor that specializes in pathology is called a pathologist. Pathologists are experts at interpreting microscopic views of body tissues.
Pediatric: Pertaining to children.
Periphery:1. The outside or surface of a structure; the portion outside the central region. See the entire definition of Periphery
Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.
Placebo-controlled: A term used to describe a method of research in which an inactive substance (a placebo) is given to one group of participants, while the treatment (usually a drug or vaccine) being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective than the placebo.
Plasma: The liquid part of the blood and lymphatic fluid, which makes up about half of its volume. Plasma is devoid of cells and, unlike serum, has not clotted. Blood plasma contains antibodies and other proteins. It is taken from donors and made into medications for a variety of blood-related conditions. Some blood plasma is also used in non-medical products.
Pneumonia: Inflammation of one or both lungs with consolidation. Pneumonia is frequently but not always due to infection. The infection may be bacterial, viral, fungal or parasitic. Symptoms may include fever, chills, cough with sputum production, chest pain, and shortness of breath.
Postpartum: In the period just after delivery, as with postpartum depression. Postpartum refers to the mother and postnatal to the baby. From the Latin post, after + partum, birth.
Preeclampsia: A condition in pregnancy characterized by abrupt hypertension (a sharp rise in blood pressure), albuminuria (leakage of large amounts of the protein albumin into the urine) and edema (swelling) of the hands, feet, and face. Preeclampsia is the most common complication of pregnancy. It affects about 5% of pregnancies. It occurs in the third trimester (the last third) of pregnancy. See the entire definition of Preeclampsia
Pregnancy: The state of carrying a developing embryo or fetus within the female body. This condition can be indicated by positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray. Pregnancy lasts for about nine months, measured from the date of the woman's last menstrual period (LMP). It is conventionally divided into three trimesters, each roughly three months long. See the entire definition of Pregnancy
Pregnant: The state of carrying a developing fetus within the body. See the entire definition of Pregnant
Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container.
Prognosis:1. The expected course of a disease. 2. The patient's chance of recovery. The prognosis predicts the outcome of a disease and therefore the future for the patient. His prognosis is grim, for example, while hers is good. See the entire definition of Prognosis
Prophylaxis: A measure taken for the prevention of a disease or condition. See the entire definition of Prophylaxis
Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein. See the entire definition of Protein
Proteins: Large molecules composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein. See the entire definition of Proteins
Public health: The approach to medicine that is concerned with the health of the community as a whole. Public health is community health. It has been said that: "Health care is vital to all of us some of the time, but public health is vital to all of us all of the time." See the entire definition of Public health
Pulmonary: Having to do with the lungs. (The word comes from the Latin pulmo for lung).
Quarantine: The period of isolation decreed to control the spread of infectious disease. Before the era of antibiotics, quarantine was one of the few available means for halting the spread of infectious diseases. It is still employed as needed. The list of quarantinable diseases in the US includes cholera, diphtheria, infectious tuberculosis, plague, smallpox, yellow fever, and viral hemorrhagic fevers (such as Marburg, Ebola and Congo-Crimean disease). In 2003, SARS (severe acute respiratory syndrome) was added as a quarantinable disease. See the entire definition of Quarantine
Radiology: The branch of medicine that uses ionizing and nonionizing radiation for the diagnosis and treatment of disease. See the entire definition of Radiology
Receptor:1. In cell biology, a structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance. There are many receptors. There is a receptor for (insulin; there is a receptor for low-density lipoproteins (LDL); etc. To take an example, the receptor for substance P, a molecule that acts as a messenger for the sensation of pain, is a unique harbor on the cell surface where substance P docks. Without this receptor, substance P cannot dock and cannot deliver its message of pain. Variant forms of nuclear hormone receptors mediate processes such as cholesterolmetabolism and fatty acid production. Some hormone receptors are implicated in diseases such as diabetes and certain types of cancer. A receptor called PXR appears to jump-start the body's response to unfamiliar chemicals and may be involved in drug-drug interactions. 2. In neurology, a terminal of a sensorynerve that receives and responds to stimuli.
Recombinant: A person with a new combination of genes, a combination of genes not present in either parent, due to parental recombination of those genes.
Recombination: The trading of fragments of genetic material between chromosomes before the egg and sperm cells are created. Key features of recombination include the point-to-point association of paired chromosomes (synapsis) followed by the visible exchange of segments (crossing over) at X-shaped crosspoints (chiasmata). Recombination is the principal way of creating genetic diversity between generations. By shuffling the genetic deck of cards, recombination ensures that children are dealt a different genetic hand than their parents.
Regimen: With the accent on the first syllable (reg as in Reggie Jackson), a regimen is a plan, a regulated course such as a diet, exercise or treatment, designed to give a good result. A low-salt diet is a regimen.
Replication: A turning back, repetition, duplication, reproduction.
Resistance: Opposition to something, or the ability to withstand it. For example, some forms of staphylococcus are resistant to treatment with antibiotics.
Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.
Respiratory failure: Inability of the lungs to perform their basic task of gas exchange, the transfer of oxygen from inhaled air into the blood and the transfer of carbon dioxide from the blood into exhaled air. The basis of respiratory failure may be failure of the exchange of oxygen and carbon dioxide within the tiny air sacs (alveoli) in the lungs; failure of the muscles required to expand the lungs; or failure of the brain centers controlling respiration. See the entire definition of Respiratory failure
Respiratory syncytial virus: A virus that causes mild respiratory infections, colds, and coughs in adults, but can produce severe respiratory problems, including bronchitis and pneumonia in young children. Persons with compromised immune, cardiac or pulmonary systems are at high risk from respiratory syncytial virus (RSV). See the entire definition of Respiratory syncytial virus
Retrospective: Looking backward on the past, on what has already taken place. A retrospective study looks backward in time, usually using medical records and interviews with patients who already known to have or have had a disease.
Retrospective study: In medicine, a study that looks backward in time, usually using medical records and interviews with patients who already known to have a disease.
Rheumatoid arthritis: An autoimmune disease which causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Autoimmune diseases occur when the body tissues are mistakenly attacked by its own immune system. The immune system is a complex organization of cells and antibodies designed normally to "seek and destroy" invaders of the body, particularly infections. Patients with these diseases have antibodies in their blood which target their own body tissues, where they can be associated with inflammation. Because it can affect multiple other organs of the body, rheumatoid arthritis is referred to as a systemic illness and is sometimes called rheumatoid disease. While rheumatoid arthritis is a chronic illness (meaning it can last for years) patients may experience long periods without symptoms. See the entire definition of Rheumatoid arthritis
Rhinorrhea: Medical term for a runny nose. From the Greek words "rhinos" meaning "of the nose" and "rhoia" meaning "a flowing."
Risk factor: Something that increases a person's chances of developing a disease.
RNA: Short for ribonucleic acid, a nucleic acid molecule similar to DNA but containing ribose rather than deoxyribose. RNA is formed upon a DNA template. There are several classes of RNA molecules. See the entire definition of RNA
Robust: In statistics, a term applied to a test or procedure that is not seriously disturbed by violations of the assumptions on which it is based. For example, it was an "unexpected and robust difference in the rate of events." (Dr. Harold J. Burstein, in The New England Journal of Medicine, Oct 9, 2003)
Roentgenology: Radiology, the science of radiation and, specifically, the use of both ionizing (like X-ray) and nonionizing (like ultrasound) modalities for the diagnosis and treatment of disease. See the entire definition of Roentgenology
RSV: Although several standard medical dictionaries indicate only that RSV stands for Rous sarcoma virus, RSV in clinical medicine is the abbreviation for respiratory syncytial virus. See: Respiratory syncytial virus.
RT-PCR (Reverse transcriptase-polymerase chain reaction): a highly sensitive technique for the detection and quantitation of mRNA (messenger RNA). The technique consists of two parts:
The synthesis of cDNA (complementary DNA) from RNA by reverse transcription (RT) and
The amplification of a specific cDNA by the polymerase chain reaction (PCR).
Rule out: A term much used in medicine, meaning to eliminate or exclude something from consideration. The ACB (albumin cobalt binding) test helps rule out a heart attack in the differential diagnosis of severe chest pain.
Runny nose: Rhinorrhea is the medical term for this common problem. From the Greek words "rhinos" meaning "of the nose" and "rhoia" meaning "a flowing."
Rupture: A break or tear in any organ (such as the spleen) or soft tissue (such as the achilles tendon). Rupture of the appendix is more likely among uninsured and minority children when they develop appendicitis.
Saline: Relating to salt. As an adjective, "saline" means "salty, containing salt." As a noun "saline" is a salt solution, often adjusted to the normal salinity of the human body. See the entire definition of Saline
Second wave: A phenomenon of infections that can develop during a pandemic. The disease infects one group of people first. Infections appear to decrease. And then, infections increase in a different part of the population, resulting in a second wave of infections.
Seizure: Uncontrolled electrical activity in the brain, which may produce a physical convulsion, minor physical signs, thought disturbances, or a combination of symptoms. See the entire definition of Seizure
Sensitivity:1. In psychology, the quality of being sensitive. As, for example, sensitivity training, training in small groups to develop a sensitive awareness and understanding of oneself and of ones relationships with others. 2. In disease epidemiology, the ability of a system to detect epidemics and other changes in disease occurrence. 3. In screening for a disease, the proportion of persons with the disease who are correctly identified by a screening test. 4. In the definition of a disease, the proportion of persons with the disease who are correctly identified by defined criteria.
Serum: The clear liquid that can be separated from clotted blood. Serum differs from plasma, the liquid portion of normal unclotted blood containing the red and white cells and platelets. It is the clot that makes the difference between serum and plasma. See the entire definition of Serum
Severe acute respiratory syndrome: A severe form of pneumonia. Abbreviated SARS. A term applied to outbreaks of a mysterious illness in Asia beginning February 1, 2003. See the entire definition of Severe acute respiratory syndrome
Shock: In medicine, shock is a critical condition brought on by a sudden drop in blood flow through the body. There is failure of the circulatory system to maintain adequate blood flow. This sharply curtails the delivery of oxygen and nutrients to vital organs. It also compromises the kidney and so curtails the removal of wastes from the body. Shock can be due to a number of different mechanisms including not enough blood volume (hypovolemic shock) and not enough output of blood by the heart (cardiogenic shock). The signs and symptoms of shock include low blood pressure (hypotension), overbreathing (hyperventilation), a weak rapid pulse, cold clammy grayish-bluish (cyanotic) skin, decreased urine flow (oliguria), and mental changes (a sense of great anxiety and foreboding, confusion and, sometimes, combativeness). See the entire definition of Shock
Shortness of breath: Difficulty in breathing. Medically referred to as dyspnea. Shortness of breath can be caused by respiratory (breathing passages and lungs) or circulatory (heart and blood vessels) conditions. See also dyspnea.
Sinus:1. An air-filled cavity in a dense portion of a skull bone. The sinuses decrease the weight of the skull. The sinuses are formed in four right-left pairs. The frontal sinuses are positioned behind the forehead, while the maxillary sinuses are behind the cheeks. The sphenoid and ethmoid sinuses are deeper in the skull behind the eyes and maxillary sinuses. The sinuses are lined by mucous-secreting cells. Air enters the sinuses through small opening in bone called ostia. If an ostium is blocked, air cannot pass into the sinus and likewise mucous cannot drain out. See also: Sinusitis. See the entire definition of Sinus
Sneeze:1. As a verb, to suddenly expel air through the nose and mouth by an involuntary contraction of the muscles of expiration. 2. As a noun, the act of sneezing. See the entire definition of Sneeze
Soothing: Bringing comfort, solace, reassurance, peace, composure, quietude. See the entire definition of Soothing
Sore:1. (adjective) A popular term for painful. I have sore fingers from typing dictionary terms. She has a sore throat. 2. (noun) A nondescript term for nearly any lesion of the skin or mucous membranes. He has a number of sores in his mouth.
Sore throat: Pain in the throat. Sore throat may be caused by many different causes, including inflammation of the larynx, pharynx, or tonsils. See the entire definition of Sore throat
Spanish flu: A pandemic of influenza A (H1N1) in 1918-19 that caused the highest number of known flu deaths. More than 500,000 people died in the United States, and 20 million to 50 million people may have died worldwide. Many people died within the first few days after infection and others died of complications soon after. Nearly half of those who died were young, healthy adults. Also known as Spanish influenza. See the entire definition of Spanish flu
Sporadic: Occurring upon occasion or in a scattered, isolated or seemingly random way. See the entire definition of Sporadic
Sputum: The mucus and other matter brought up from the lungs, bronchi, and trachea that one may cough up and spit out or swallow. The word "sputum" is borrowed directly from the Latin "to spit." Called also expectoration.
Stage: As regards cancer, the extent of a cancer, especially whether the disease has spread from the original site to other parts of the body. See also: Staging.
Strain: 1. An injury to a tendon or muscle resulting from overuse or trauma. 2. A hereditary tendency that originated from a common ancestor. 3. To exert maximum effort. 4. To filter.
Stress: Forces from the outside world impinging on the individual. Stress is a normal part of life that can help us learn and grow. Conversely, stress can cause us significant problems. See the entire definition of Stress
Substance:1. Material with particular features, as a pressor substance. 2. The material that makes up an organ or structure. Also known in medicine as the substantia. 3. A psychoactive drug as, for example, in substance abuse.
Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office. See the entire definition of Surgery
Swine flu: A respiratory illness of pigs caused by infection with swine influenza A virus (SIV). While swine flu viruses normally do not infect humans, occasional infections of humans do occur. Human cases of swine influenza A virus infection occur in individuals who have had a history of recent direct contact with pigs or close (within 6 feet) contact with pigs. Rare instances of human-to-human transmission have been documented. Swine flu infections have also occurred in individuals with no history of exposure to pigs. Symptoms typically range from a mild respiratory illness to flu-like symptoms with fever. Treatment involves the use of antiviral medications begun as soon as possible after the onset of symptoms. Vaccines are available to be given to pigs to prevent swine flu in these animals. See the entire definition of Swine flu
Symptom: Any subjective evidence of disease. Anxiety, lower back pain, and fatigue are all symptoms. They are sensations only the patient can perceive. In contrast, a sign is objective evidence of disease. A bloody nose is a sign. It is evident to the patient, doctor, nurse and other observers.
Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease. See the entire definition of Syndrome
Systemic: Affecting the entire body. A systemic disease such as diabetes can affect the whole body. Systemic chemotherapy employs drugs that travel through the bloodstream and reach and affect cells all over the body.
The Lancet: A weekly medical journal headquartered in London. Published uninterruptedly and with the same title since 1823, The Lancet is "the longest running medical journal in the world." See the entire definition of The Lancet
Thimerosal: A mercury-containing preservative used in some vaccines and other products since the 1930's. No harmful effects were reported from thimerosal at doses used in vaccines, except for minor local reactions like redness and swelling at the injection site. There was specifically no evidence that thimerosal increases the risk of developing autism or any other behavior disorder. However, in 1999 it was agreed that thimerosal should be reduced or eliminated in vaccines as a precautionary measure. Today, all routinely recommended pediatric vaccines in the US contain no thimerosal or only trace amounts.
Thoracic: Pertaining to the chest.
Throat: The throat is the anterior (front) portion of the neck beginning at the back of the mouth, consisting anatomically of the pharynx and larynx. The throat contains the trachea and a portion of the esophagus.
Transplant: The grafting of a tissue from one place to another, just as in botany a bud from one plant might be grafted onto the stem of another. The transplanting of tissue can be from one part of the patient to another (autologous transplantation), as in the case of a skin graft using the patient's own skin; or from one patient to another (allogenic transplantation), as in the case of transplanting a donor kidney into a recipient.
Trimester: The nine months of pregnancy is traditionally divided into three trimesters: distinct periods of roughly three months in which different phases of fetal development take place. See the entire definition of Trimester
Urine: Liquid waste. The urine is a clear, transparent fluid. It normally has an amber color. The average amount of urine excreted in 24 hours is from 40 to 60 ounces (about 1,200 cubic centimeters). Chemically, the urine is mainly an aqueous (watery) solution of salt (sodium chloride) and substances called urea and uric acid. Normally, it contains about 960 parts of water to 40 parts of solid matter. Abnormally, it may contain sugar (in diabetes), albumen (a protein) (as in some forms of kidney disease), bile pigments (as in jaundice), or abnormal quantities of one or another of its normal components.
USDA: US Department of Agriculture.
Vaccination: Injection of a killed microbe in order to stimulate the immune system against the microbe, thereby preventing disease. Vaccinations, or immunizations, work by stimulating the immune system, the natural disease-fighting system of the body. The healthy immune system is able to recognize invading bacteria and viruses and produce substances (antibodies) to destroy or disable them. Immunizations prepare the immune system to ward off a disease. To immunize against viral diseases, the virus used in the vaccine has been weakened or killed. To only immunize against bacterial diseases, it is generally possible to use a small portion of the dead bacteria to stimulate the formation of antibodies against the whole bacteria. In addition to the initial immunization process, it has been found that the effectiveness of immunizations can be improved by periodic repeat injections or "boosters." Also see Vaccines (in the plural) and Vaccine of a specific type (such Vaccine, Polio).
Vaccines: Microbial preparations of killed or modified microorganisms that can stimulate an immune response in the body to prevent future infection with similar microorganisms. These preparations are usually delivered by injection.
Ventilation: The exchange of air between the lungs and the atmosphere so that oxygen can be exchanged for carbon dioxide in the alveoli (the tiny air sacs in the lungs). See the entire definition of Ventilation
Ventilator: A ventilator is a machine which mechanically assists patients in the exchange of oxygen and carbon dioxide (sometimes referred to as artificial respiration).
Viable: Capable of life. For example, a viable premature baby is one who is able to survive outside the womb.
Viral: Of or pertaining to a virus. For example, "My daughter has a viral rash."
Viral infection: Infection caused by the presence of a virus in the body. Depending on the virus and the person's state of health, various viruses can infect almost any type of body tissue, from the brain to the skin. Viral infections cannot be treated with antibiotics; in fact, in some cases the use of antibiotics makes the infection worse. The vast majority of human viral infections can be effectively fought by the body's own immune system, with a little help in the form of proper diet, hydration, and rest. As for the rest, treatment depends on the type and location of the virus, and may include anti-viral or other drugs.
Virology: The study of viruses.
Virulence: The ability of any agent of infection to produce disease. The virulence of a microorganism (such as a bacterium or virus) is a measure of the severity of the disease it is capable of causing. See the entire definition of Virulence
Virulent: Extremely noxious, damaging, deleterious, disease-causing (pathogenic). Marked by a rapid, severe, and malignant course. Poisonous, venomous. See the entire definition of Virulent
Virus: A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult. See the entire definition of Virus
Viruses: Small living particles that can infect cells and change how the cells function. Infection with a virus can cause a person to develop symptoms. The disease and symptoms that are caused depend on the type of virus and the type of cells that are infected.
Vitamins: The word "vitamin" was coined in 1911 by the Warsaw-born biochemist Casimir Funk (1884-1967). At the Lister Institute in London, Funk isolated a substance that prevented nerve inflammation (neuritis) in chickens raised on a diet deficient in that substance. He named the substance "vitamine" because he believed it was necessary to life and it was a chemical amine. The "e" at the end was later removed when it was recognized that vitamins need not be amines. See the entire definition of Vitamins
Voluntary: Done in accordance with the conscious will of the individual. The opposite of involuntary. See the entire definition of Voluntary
World Health Organization: An agency of the United Nations established in 1948 to further international cooperation in improving health conditions. Although the World Health Organization inherited specific tasks relating to epidemic control, quarantine measures, and drug standardization from the Health Organization of the League of Nations (that was set up in 1923) and from the International Office of Public Health at Paris (established in 1909), the World Health Organization was given a broad mandate under its constitution to promote the attainment of "the highest possible level of health" by all people. WHO defines health positively as "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity." See the entire definition of World Health Organization
Youth: The time between childhood and maturity. (Unfortunately, as the songwriter Sammy Cahn noted, "youth is wasted on the young.")
Pneumonia is inflammation of one or both lungs with consolidation. Pneumonia is frequently but not always due to infection. The infection may be bacterial, viral, fungal or parasitic. Symptoms may include fever, chills, cough with sputum production, chest pain, and shortness of breath.
Most sore throats are caused by viruses or mechanical causes (such as mouth breathing) and can be treated successfully at home. However, a person should be seen by a health care professional if they have a sore throat that has a rapid onset, and is associated with a fever or tenderness of the front of the neck; a sore throat that causes the person to have difficulty swallowing (not just pain swallowing) or breathing; or if a sore throat lasts for more than a week.
Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.
Headaches can be divided into two categories: primary headaches and secondary headaches. Migraine headaches, tension headaches, and cluster headaches are considered primary headaches. Secondary headaches are caused by disease. Headache symptoms vary with the headache type. Over-the-counter pain relievers provide short-term relief for most headaches.
Chronic cough is a cough that does not go away and is generally a symptom of another disorder such as asthma, allergic rhinitis, sinus infection, cigarette smoking, GERD, postnasal drip, bronchitis, pneumonia, medications, and less frequently tumors or other lung disease. Treatment of chronic cough is dependant upon the cause.
Nausea is an uneasiness of the stomach that often precedes vomiting. Nausea and vomiting are not diseases, but they are symptoms of many conditions. The causes of vomiting differ according to age, and treatment depends upon the cause of nausea and vomiting.
Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms.
Epilepsy is a brain disorder in which the person has seizures. There are two kinds of seizures, focal and generalized. There are many causes of epilepsy. Treatment of epilepsy (seizures) depends upon the cause and type of seizures experienced.
Influenza (flu) is a respiratory illness caused by a virus. Flu symptoms include fever, cough, sore throat, runny nose, headache, fatigue, and muscle aches. The flu may be prevented with an annual influenza vaccination.
Bird flu (avian flu, avian influenza) infection in humans may result from contact with infected poultry. There is a vaccine to prevent human infection with the H5N1 strain of the avian flu virus.
Guillain-Barre Syndrome is an autoimmune disease of the nervous system due to damage to the myelin sheath around nerves. It is the most acquired nerve disease (neuropathy) and usually follows a virus infection but can also be associated with immunizations, surgery, and childbirth. The cause is unknown but appears to be related to autoimmune reaction. Symptoms include weakness beginning in the legs and progressing upward, lost reflexes, and in severe cases breathing can be affected. Patients can expect a slow but progressive recovery over several months maintaining vital functions and passively exercising the muscles. Plasmapheresis (removing toxic substances from the blood) has been shown to improve outcome and shorten the disease as well as intravenous immunoglobulin.
Kids get headaches and migraines too. Many adults with headaches started having them as kids, in fact, 20% of adult headache sufferers say their headaches started before age 10, and 50% report their headaches started before age 20.
Severe acute respiratory syndrome (SARS) is a respiratory disease caused by the coronavirus SARS-CoV. Symptoms include fever and shortness of breath. Patients with SARS often require oxygen and severe cases require mechanical ventilation.
Pregnant and women who are breastfeeding are encouraged to receive the seasonal flu shot as well as the 2009 H1N1 influenza (swine flu) vaccine. H1N1 flu is treated with the medications Tamiflu® (oseltamivir) or Relenza® (zanamivir). Pregnant women should not receive the H1N1 attenuated nasal spray vaccine. Possible side effects of the H1N1 flu vaccine include muscle aches, fever, nausea, tiredness, or headache.
Pneumonia is a lung infection that can be caused by
different types of microorganisms, including bacteria, viruses, and fungi.
Symptoms of pneumonia include cough with sputum
production, fever, and sharp chest pain on inspiration (breathing in).
Pneumonia is suspected when a doctor hears abnormal
sounds in the chest, and the diagnosis is confirmed by a chest X-ray.
Bacteria causing pneumonia can be identified by sputum
culture.
A pleural effusion is a fluid collection around the
inflamed lung.
Bacterial and fungal (but not viral)
pneumonia can be treated with antibiotics.
What is pneumonia?
Pneumonia is an infection of one or both lungs which is usually caused by bacteria, viruses, or fungi. Prior to the discovery of antibiotics, one-third of all people who developed pneumonia subsequently died fro...
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