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February 10, 2012


Brain Infection Glossary of Terms

The following are health and medical definitions of terms that appear in the Brain Infection article.

Abscess: A local accumulation of pus anywhere in the body. The following are some examples of abscesses:

  1. A skin abscess is better known as a common boil;
  2. A peritonsillar abscess is a persistent collection of pus behind the tonsils; and
  3. A perianal abscess is a pool of pus that forms next to the anus, often causing considerable tenderness and swelling in that area and pain on sitting down and on defecating.

Acquired: Anything that is not present at birth but develops some time later. In medicine, the word "acquired" implies "new" or "added." An acquired condition is "new" in the sense that it is not genetic (inherited) and "added" in the sense that was not present at birth.
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Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
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Amputation: Removal of part or all of a body part enclosed by skin. For example, removal of part of a finger or an entire finger would be termed an amputation. Removal of an appendix, on the other hand, would not be termed amputation. A person who has undergone an amputation is called an amputee.
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Analysis: A psychology term for processes used to gain understanding of complex emotional or behavioral issues.

Antibiotic: A drug used to treat infections caused by bacteria and other microorganisms. Originally, an antibiotic was a substance produced by one microorganism that selectively inhibits the growth of another. Synthetic antibiotics, usually chemically related to natural antibiotics, have since been produced that accomplish comparable tasks.
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Antiviral: An agent that kills a virus or that suppresses its ability to replicate and, hence, inhibits its capability to multiply and reproduce.
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Arms: An appendage in anatomy and in clinical trials. See: Arm.

Back pain: Pain felt in the low or upper back. There are many causes of back pain.
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Bacteria: Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life).
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Bacterial: Of or pertaining to bacteria. For example, a bacterial lung infection.

Blindness: Loss of useful sight. Blindness can be temporary or permanent. Damage to any portion of the eye, the optic nerve, or the area of the brain responsible for vision can lead to blindness. There are numerous (actually, innumerable) causes of blindness. The current politically correct terms for blindness include visually handicapped and visually challenged.

Brain: That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."

Brain swelling: See: Cerebral edema.

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.

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Cardiac: Having to do with the heart.

Cardiac muscle: A type of muscle with unique features only found in the heart. The cardiac muscle is the muscle of the heart and medically is called the myocardium ("myo-" being the prefix renoting muscle).

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."
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Cerebral: Pertaining to the brain, the cerebrum or the intellect.
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Cerebrospinal fluid: CSF. A watery fluid, continuously produced and absorbed, which flows in the ventricles (cavities) within the brain and around the surface of the brain and spinal cord.
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Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
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Coma: A state of deep unarousable unconsciousness.
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Complication: In medicine, an additional problem that arises following a procedure, treatment or illness and is secondary to it. A complication complicates the situation.

Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.

CT scan: Computerized tomography scan. Pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them into pictures on a screen. CT stands for computerized tomography.
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Cysticercosis: An infection caused by the pork tapeworm, Taenia solium. Infection occurs when the tapeworm larvae enter the body and form cysticerci (SIS-tuh-sir-KEY) (cysts). When cysticerci are found in the brain, the condition is called neurocysticercosis (NEW-row SIS-tuh-sir-KO-sis).
See the entire definition of Cysticercosis

Deafness: Deafness is defined by partial or complete hearing loss. Levels of hearing impairment vary from a mild but important loss of sensitivity to a total loss of hearing. Older adults suffer most often from hearing loss. Age-related hearing loss affects 30 to 35 percent of the population between the ages of 65 and 75 years, and 40 percent of the population over the age of 75. The most common cause of hearing loss in children is otitis media, a disorder that affects predominantly infants and young children. A substantial number of hearing impairments are caused by environmental factors such as noise, drugs, and toxins. Many sensorineural hearing losses result from a genetic predisposition.

Delirium: A sudden state of severe confusion and rapid changes in brain function, sometimes associated with hallucinations and hyperactivity, in which the patient is inaccessible to normal contact. Symptoms may include inability to concentrate and disorganized thinking evidenced by rambling, irrelevant, or incoherent speech. There may be a reduced level of consciousness, sensory misperceptions and illusions, disturbances of sleep, drowsiness, disorientation to time, place, or person, and problems with memory.
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Dementia: Significant loss of intellectual abilities such as memory capacity, severe enough to interfere with social or occupational functioning.
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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).
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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.
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Digestive system: The organs that are responsible for getting food into and out of the body and for making use of it. These organs include the salivary glands, the mouth, esophagus, stomach, small intestine, liver, gallbladder, pancreas, colon, rectum, and anus.
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Electrolyte: An electrolyte is a substance that will dissociate into ions in solution and acquire the capacity to conduct electricity. The electrolytes include sodium, potassium, chloride, calcium and phosphate. Informally, called lytes. (The clue to the word electrolyte is in the lyte which comes from the Greek lytos meaning that may be dissolved.)

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.
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Encephalitis: Inflammation of the brain. Encephalitis occurs, for example, in 1 in 1,000 cases of measles. It may start (up to 3 weeks) after onset of the measles rash and present with high fever, convulsions, and coma. It usually runs a blessedly short course with full recovery within a week. Or it may eventuate in central nervous system impairment or death.
See the entire definition of Encephalitis

Escherichia coli: Full term for E. coli, the colon bacillus.

Extremity: The extremities in medical language are not freezing cold or scorching heat but rather the uttermost parts of the body. The extremities are simply the hands and feet.
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Feces: The medical and scientific term for the "excrement discharged from the intestines."
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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.).
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Flexion: The process of bending or the state of being bent. Flexion of the fingers results in a clenched fist.

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.

Fungal: Pertaining to a fungus. For example, a fungal skin infection.

Fungi: Plural of fungus.

Germ: 1. A cell or group of cells (called a primordium) capable of developing into an organ, a part or an organism in its entirety. Eggs and sperm are germ cells.

2. A pathogenic a microorganism. A microbe capable of causing disease. The germ theory of disease held, correctly, that these minute bodies can cause disease.

3. The figurative source or wellspring. Dr. Watson told Holmes he had the germ of an idea.
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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.
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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.
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Herpes: A family of viruses. Herpes also refers to infection with one of the human herpesviruses, especially herpes simplex types 1 and 2.
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HIB: Abbreviation for Haemophilus influenzae type B.

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

Human immunodeficiency virus: HIV, the cause of AIDS. 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). Although the American research Robert Gallo at the National Institutes of Health believed he was the first to find HIV, it is now generally accepted that the French physician Luc Montagnier (1932-) and his team at the Pasteur Institute discovered HIV in 1983- 84.

Immune: Protected against infection. The Latin immunis means free, exempt.

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.
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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).

Immunodeficiency: Inability to mount a normal immune response. Immunodeficiency can be due to a genetic disease or acquired as in AIDS due to HIV.

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.

Infant: A child up to 2 years (24 months) of age.
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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.
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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.
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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.

Insertion: Chromosome abnormality due to insertion of a segment from one chromosome into another chromosome.

Intracranial: Within the cranium, the bony dome that houses and protects the brain.
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Involuntary: Done other than in accordance with the conscious will of the individual. The opposite of voluntary.
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Knee: The knee is a joint which has three parts. The thigh bone (the femur) meets the large shin bone (the tibia) to form the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap (the patella) joins the femur to form a third joint, called the patellofemoral joint. The patella protects the front of the knee joint.
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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."

Learning disability: A childhood disorder characterized by difficulty with certain skills such as reading or writing in individuals with normal intelligence. Learning disorders affect the ability to interpret what one sees and hears or the ability to link information from different parts of the brain. These limitations can show up in many ways -- as specific difficulties with spoken and written language, coordination, self-control, or attention. Such difficulties extend to schoolwork and can impede learning to read or write, or to do math.
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Libido: 1. Sexual drive. 2. In psychoanalysis, the psychic energy from all instinctive biological drives.
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Listeria: A group of bacteria capable of causing illness including potentially fatal infections in the elderly, newborns, pregnant women, and persons with a weakened immune system. Listeria monocytogenes is the form of Listeria most commonly responsible for infections.
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Lumbar: Referring to the 5 lumbar vertebrae which are situated below the thoracic vertebrae and above the sacral vertebrae in the spinal column. The 5 lumbar vertebrae are represented by the symbols L1 through L5. There are correspondingly 5 lumbar nerves.

Lumbar puncture: A lumbar puncture or "LP" is a procedure whereby spinal fluid is removed from the spinal canal for the purpose of diagnostic testing. It is particularly helpful in the diagnosis of inflammatory diseases of the central nervous system, especially infections, such as meningitis. It can also provide clues to the diagnosis of stroke, spinal cord tumor and cancer in the central nervous system.
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Malaise: A vague feeling of discomfort, one that cannot be pinned down but is often sensed as "just not right."
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Measles: An acute and highly contagious viral disease characterized by fever, runny nose, cough, red eyes, and a spreading skin rash. Measles, also known as rubeola, is a potentially disastrous disease. It can be complicated by ear infections, pneumonia, encephalitis (which can cause convulsions, mental retardation, and even death), the sudden onset of low blood platelet levels with severe bleeding (acute thrombocytopenic purpura), or a chronic brain disease that occurs months to years after an attack of measles (subacute sclerosing panencephalitis).
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Meninges: The three membranes that cover the brain and spinal cord (singular: meninx).
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Meningitis: Inflammation of the meninges, usually due to a bacterial infection but sometimes from viral, protozoan, or other causes (in some cases the cause cannot be determined).
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Meningococcal meningitis: Inflammation of the meninges (the membranes covering of the brain and spinal cord) due to infection with the meningococcus bacterium Neisseria meningitidis.
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Mental retardation: A term used when a person has certain limitations in mental functioning and in skills such as communicating, taking care of him or herself, and social skills. These limitations will cause a child to learn and develop more slowly than a typical child. Children with mental retardation may take longer to learn to speak, walk, and take care of their personal needs such as dressing or eating. They are likely to have trouble learning in school. They will learn, but it will take them longer. There may be some things they cannot learn. As many as 3 out of every 100 people have mental retardation. In fact, 1 out of every 10 children who need special education has some form of mental retardation.
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Motor: In medicine, having to do with the movement of a part of the body. Something that produces motion or refers to motion. For example, a motor neuron is a nerve cell that conveys an impulse to a muscle causing it to contract. The term "motor" today is also applied to a nerve that signals a gland to secrete. Motor is as opposed to sensory.

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.

MRI: Abbreviation and nickname for magnetic resonance imaging. For more information, see: Magnetic Resonance Imaging; Paul C. Lauterbur; Peter Mansfield.

Mumps: An acute (sudden, shortlived) viral illness that usually presents with inflammation of the salivary glands, particularly the parotid glands. A child with mumps often looks like a chipmunk with a full mouth due to the swelling of the parotids (the salivary glands near the ears).
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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.

Myelitis: Inflammation of the spinal cord.

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.

Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.

Neck pain: Neck pain is the sensation of discomfort in the neck area. Neck pain can result from disorders of any of the structures in the neck, including the cervical vertebrae and intervertebral discs, nerves, muscles, blood vessels, esophagus, larynx, trachea, lymphatic organs, thyroid gland, or parathyroid glands. Neck pain arises from numerous different conditions and is sometimes referred to as cervical pain.

Neisseria: Group of bacteria that includes the cause of gonorrhea.

Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system.

Neurosurgeon: A physician trained in surgery of the nervous system and who specializes in surgery on the brain and other parts of the nervous system. Sometimes called a "brain surgeon."

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Nose: The external midline projection from the face.
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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.
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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.
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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.
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Panic: A sudden strong feeling of fear that prevents reasonable thought or action.
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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.

Parasite: An organism that lives in or on and takes its nourishment from another organism. A parasite cannot live independently.
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Parasitic: Having to do with a parasite, as in a parasitic infection; or acting like a parasite by taking nourishment from another.

Pediatric: Pertaining to children.

Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.

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.

Polio: Abbreviation for poliomyelitis, an acute and sometimes devastating disease caused by a virus. Man is the only natural host for polio virus. The virus enters the mouth and multiplies in lymphoid tissues in the throat and intestine. Small numbers of virus enter the blood and go to other sites where the virus multiplies more extensively. Another round of viremia (virus in the bloodstream) leads to invasion of the central nervous system (CNS), the spinal cord and brain, the target sites struck by the virus.
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Poliomyelitis: An acute and sometimes devastating viral disease. Man is the only natural host for poliovirus. The virus enters the mouth and multiplies in lymphoid tissues in the pharynx and intestine. Small numbers of virus enter the blood and go to other sites where the virus multiplies more extensively. Another round of viremia (virus in the bloodstream) leads to invasion of the central nervous system (CNS), the spinal cord and brain, the key sites struck by the virus.
See the entire definition of Poliomyelitis

Poliovirus: A member of the enterovirus subgroup, family Picornaviridae. Enteroviruses are transient inhabitants of the gastrointestinal tract. Picornaviruses are small viruses with an RNA genome. There are three strains of poliovirus. They are called P1 or the Brunhilde virus, P2 or the Lansing virus, and P3 or the Leon virus). Immunity to one strain of poliovirus does not produce significant immunity to the other two strains. Poliovirus is rapidly inactivated by heat, formaldehyde, chlorine, or ultraviolet (UV) light.

Pork tapeworm: Taenia solium.

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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.
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Pregnant: The state of carrying a developing fetus within the body.
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Prion: A disease-causing agent that is neither bacterial nor fungal nor viral and contains no genetic material. A prion is a protein that occurs normally in a harmless form. By folding into an aberrant shape, the normal prion turns into a rogue agent. It then coopts other normal prions to become rogue prions.
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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.
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Psychiatric: Pertaining to or within the purview of psychiatry, the medical specialty concerned with the prevention, diagnosis, and treatment of mental illness.
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Pupil: The opening of the iris. The pupil may appear to open (dilate) and close (constrict) but it is really the iris that is the prime mover; the pupil is merely the absence of iris. The pupil determines how much light is let into the eye. Both pupils are usually of equal size. If they are not, that is termed anisocoria (from "a-", not + "iso", equal + "kore", pupil = not equal pupils).
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Rabies: A potentially fatal viral infection that attacks the central nervous system.
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Rash: Breaking out (eruption) of the skin. Medically, a rash is referred to as an exanthem.

Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.

Roundworm: A type of parasitic worm that hatches in the intestines and lives there. The eggs of the roundworm usually enter the body through contaminated water or food or on fingers placed in the mouth after the hands have touched a contaminated object.
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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.

Saliva: a watery secretion in the mouth produced by the salivary glands that aids in the digestion of food. Saliva also serves to moisten and cleanse the mouth, including the tongue and teeth, and contains substances that can play a role in the prevention of infection. Saliva aids digestion by moistening food and contains enzymes that begin the digestion process. Also known as spit.

Scan: As a noun, the data or image obtained from the examination of organs or regions of the body by gathering information with a sensing device.
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Seizure: Uncontrolled electrical activity in the brain, which may produce a physical convulsion, minor physical signs, thought disturbances, or a combination of symptoms.
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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).
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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.
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Spinal cord: The major column of nerve tissue that is connected to the brain and lies within the vertebral canal and from which the spinal nerves emerge. Thirty-one pairs of spinal nerves originate in the spinal cord: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. The spinal cord and the brain constitute the central nervous system (CNS). The spinal cord consists of nerve fibers that transmit impulses to and from the brain. Like the brain, the spinal cord is covered by three connective-tissue envelopes called the meninges. The space between the outer and middle envelopes is filled with cerebrospinal fluid (CSF), a clear colorless fluid that cushions the spinal cord against jarring shock. Also known simply as the cord.
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Spinal tap: Also known as a lumbar puncture or "LP", a spinal tap is a procedure whereby spinal fluid is removed from the spinal canal for the purpose of diagnostic testing. It is particularly helpful in the diagnosis of inflammatory diseases of the central nervous system, especially infections, such as meningitis. It can also provide clues to the diagnosis of stroke, spinal cord tumor and cancer in the central nervous system.
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Spine: 1) The column of bone known as the vertebral column, which surrounds and protects the spinal cord. The spine can be categorized according to level of the body: i.e., cervical spine (neck), thoracic spine (upper and middle back), and lumbar spine (lower back). See also vertebral column. 2) Any short prominence of bone. The spines of the vertebrae protrude at the base of the back of the neck and in the middle of the back. These spines protect the spinal cord from injury from behind.

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.

Streptococcus: A group of bacteria, familiarly known as strep, that cause a multitude of diseases. The name comes from the Greek strepto- meaning twisted + kokkos meaning berry, and that is exactly what strep look like under the microscope, like a twisted bunch of little round berries. Illness caused by strep includes strep throat, strep pneumonia, scarlet fever, rheumatic fever (and rheumatic heart valve damage), glomerulonephritis, the skin disorder erysipelas, and PANDAS.

Tapeworm:A worm that is flattened like a tape measure and functions as an intestinal parasite, unable to live freely on its own but able to do so within an animal's gut. The eggs usually enter the body via raw or uncooked beef. Symptoms of their presence are usually absent. However, some patients experience abdominal pain, fatigue, weight loss, and diarrhea. Treatment with medication results in a cure within days.

Therapy: The treatment of disease.
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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.

Toxoplasma gondii: A single-celled parasite that causes toxoplasmosis (toxo) .
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Trauma: Any injury, whether physically or emotionally inflicted. "Trauma" has both a medical and a psychiatric definition. Medically, "trauma" refers to a serious or critical bodily injury, wound, or shock. This definition is often associated with trauma medicine practiced in emergency rooms and represents a popular view of the term. In psychiatry, "trauma" has assumed a different meaning and refers to an experience that is emotionally painful, distressful, or shocking, which often results in lasting mental and physical effects.
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Trichinella spiralis: The worm that causes trichinosis. Trichinella spiralis larvae can infest pigs and wild game, hibernating in muscle tissue within a protective cyst.
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Trichinosis: See: Trichinellosis.

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.
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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.

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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.

Vein: A blood vessel that carries blood low in oxygen content from the body back to the heart. The deoxygenated form of hemoglobin (deoxyhemoglobin) in venous blood makes it appear dark. Veins are part of the afferent wing of the circulatory system which returns blood to the heart.
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Vertebrae: The preferred plural of vertebra. (The alternate plural is vertebras.) See also: Cervical vertebrae; Coccygeal vertebrae; Lumbar vertebrae; Sacral vertebrae; and Thoracic vertebrae.

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.

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.
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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.

Vomit: Matter from the stomach that has come up into and may be ejected beyond the mouth, due to the act of vomiting.
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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."
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X-ray: 1. High-energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances (to varying extents), of acting on a photographic film or plate (permitting radiography), and of causing a fluorescent screen to give off light (permitting fluoroscopy). In low doses X-rays are used for making images that help to diagnose disease, and in high doses to treat cancer. Formerly called a Roentgen ray. 2. An image obtained by means of X-rays.

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Brain Infection

West Nile Virus Overview

West Nile virus is transmitted to humans by a mosquito bite. The virus can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord).

West Nile virus was discovered in 1937 in the West Nile district of Uganda. New interest was created when West Nile emerged in the United States for the first time in the New York City area in August 1999. There were 62 confirmed human cases and 7 deaths during this outbreak, creating widespread concern.

  • Since the initial 1999 New York City outbreak, the cases of West Nile encephalitis have been relatively limited. In 2002, there were a total of 480 reported cases in humans and 24 deaths (as of August 28, 2002).
  • The distribution of the virus is spreading across the United States, as determined from surveillance of infected birds by the Centers for Disease Control and Prevention. In a little more than a ye...

Read the West Nile Virus article »


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