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Hepatitis B Glossary of Terms

The following are health and medical definitions of terms that appear in the Hepatitis B article.

Abdomen: The belly , that part of the body that contains all of the structures between the chest and the pelvis . The abdomen is separated anatomically from the chest by the diaphragm , the powerful muscle spanning the body cavity below the lungs .
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Abdominal: Relating to the abdomen, the belly , that part of the body that contains all of the structures between the chest and the pelvis . The abdomen is separated anatomically from the chest by the diaphragm , the powerful muscle spanning the body cavity below the lungs .
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Abdominal cavity: The cavity within the abdomen, the space between the abdominal wall and the spine.
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Abdominal pain: Pain in the belly (the abdomen). Abdominal pain can come from conditions affecting a variety of organs. The abdomen is an anatomical area that is bounded by the lower margin of the ribs above, the pelvic bone (pubic ramus) below, and the flanks on each side. Although abdominal pain can arise from the tissues of the abdominal wall that surround the abdominal cavity (the skin and abdominal wall muscles), the term abdominal pain generally is used to describe pain originating from organs within the abdominal cavity (from beneath the skin and muscles). These organs include the stomach, small intestine, colon, liver, gallbladder, and pancreas.
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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 ).
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Absorption: Uptake. In the biomedical sciences, absorption has diverse specific meanings.
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Acquired: Anything that is not present at birth but develops some time later. In medicine, the word "acquired" implies "new" or "added." An acquired condition is "new" in the sense that it is not genetic (inherited) and "added" in the sense that was not present at birth.
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Acupuncture: The practice of inserting needles into the body to reduce pain or induce anesthesia . More broadly, acupuncture is a family of procedures involving the stimulation of anatomical locations on or in the skin by a variety of techniques. There are a number of different approaches to diagnosis and treatment in American acupuncture that incorporate medical traditions from China, Japan, Korea, and other countries. The most thoroughly studied mechanism of stimulation of acupuncture points employs penetration of the skin by thin, solid, metallic needles, which are manipulated manually or by electrical stimulation.
See the entire definition of Acupuncture

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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Anaphylaxis: Allergic reaction. In severe cases, this can include potentially deadly anaphylactic shock.

Anemia: The condition of having less than the normal number of red blood cells or less than the normal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased.
See the entire definition of Anemia

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.
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Antigen: A substance that is capable of causing the production of an antibody .
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Antiretroviral: An agent or process effective against a retrovirus. For example, a drug to treat HIV.

Anxiety: A feeling of apprehension and fear characterized by physical symptoms such as palpitations , sweating, and feelings of stress . Anxiety disorders are serious medical illnesses that affect approximately 19 million American adults. These disorders fill people's lives with overwhelming anxiety and fear. Unlike the relatively mild, brief anxiety caused by a stressful event such as a business presentation or a first date, anxiety disorders are chronic, relentless, and can grow progressively worse if not treated.
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Arthritis: Inflammation of a joint. When joints are inflamed they can develop stiffness, warmth, swelling, redness and pain. There are over 100 types of arthritis. (see osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, lupus, gout, pseudogout).

Ascites: Abnormal buildup of fluid in the abdomen. Ascites can occur as a result of a number of conditions, including severe liver disease and the presence of malignant cells within the abdomen.

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

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.
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Bile: Bile is a yellow-green fluid that is made by the liver, stored in the gallbladder and passes through the common bile duct into the duodenum where it helps digest fat. The principal components of bile are cholesterol, bile salts, and the pigment bilirubin.
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Bilirubin: A yellow-orange compound produced by the breakdown of hemoglobin from red blood cells.
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Biopsy: The removal of a sample of tissue for purposes of diagnosis. (Many definitions of "biopsy" stipulate that the sample of tissue is removed for examination under a microscope. This may or may not be the case. The diagnosis may be achieved by other means such as by analysis of chromosomes or genes.)
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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".

Bone marrow: The soft blood-forming tissue that fills the cavities of bones and contains fat and immature and mature blood cells, including white blood cells, red blood cells, and platelets. Diseases or drugs that affect the bone marrow can affect the total counts of these cells.

Bowel: Another name for the intestine . The small bowel and the large bowel are the small intestine and large intestine , respectively.
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Breast milk: Milk from the breast . Human milk contains a balance of nutrients that closely matches infant requirements for brain development, growth and a healthy immune system . Human milk also contains immunologic agents and other compounds that act against viruses , bacteria , and parasites. Since an infant's immune system is not fully developed until age 2, human milk provides a distinct advantage over formula.
See the entire definition of Breast milk

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

Carcinoma: Cancer that begins in the skin or in tissues that line or cover body organs. For example, carcinoma can arise in the breast , colon, liver, lung, prostate, and stomach.
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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).
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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 .
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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

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.
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Cirrhosis: An abnormal liver condition characterized by irreversible scarring of the liver. Alcohol and viral hepatitis B and C are among the many causes of cirrhosis. Cirrhosis can cause yellowing of the skin (jaundice), itching, and fatigue. Diagnosis of cirrhosis can be suggested by physical examination and blood tests, and can be confirmed by liver biopsy in some patients. Complications of cirrhosis include mental confusion, coma, fluid accumulation (ascites), internal bleeding, and kidney failure. Treatment of cirrhosis is designed to limit any further damage to the liver as well as complications. Liver transplantation is becoming an important option for patients with advanced cirrhosis.

Coma: A state of deep unarousable unconsciousness.
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Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.

Cure: 1. To heal, to make well, to restore to good health. Cures are easy to claim and, all too often, difficult to confirm.
2. A time without recurrence of a disease so that the risk of recurrence is small, as in the 5-year cure rate for malignant melanoma .
3. Particularly in the past, a course of treatment. For example, take a cure at a spa.
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Depression : An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.
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Detoxify: To reduce or eliminate the toxicity of a substance or poison. To promote the recovery of a person from an addictive drug such as alcohol or heroin.

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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Dialysis: The process of cleansing the blood by passing it through a special machine. Dialysis is necessary when the kidneys are not able to filter the blood. Dialysis allows patients with kidney failure a chance to live productive lives. There are two types of dialysis: hemodialysis and peritoneal dialysis. Each type of dialysis has advantages and disadvantages. Patients can often choose the type of long term dialysis that best matches their needs.

Discharge: 1.The flow of fluid from part of the body, such as from the nose or vagina.
2. The passing of an action potential, such as through a nerve or muscle fiber .
3. The release of a patient from a course of care. The doctor may then dictate a discharge summary.
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DNA: Deoxyribonucleic acid. One of two types of molecules that encode genetic information. (The other is RNA . In humans DNA is the genetic material; RNA is transcribed from it. In some other organisms, RNA is the genetic material and, in reverse fashion, the DNA is transcribed from it.)
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DNA virus: A virus in which the genetic material is DNA rather than RNA. The DNA may be either double- or single-stranded.
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Dysfunction: Difficult function or abnormal function.
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ENGERIX-B: A vaccine against hepatitis B (hep B) to stimulate the body's immune system to produce antibodies against the hep B virus.


See the entire definition of Enlarged liver


See the entire definition of Enlarged spleen

Esophageal: Pertaining to the esophagus.

Family history: The family structure and relationships within the family, including information about diseases in family members.
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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.
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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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Genetic: Having to do with genes and genetic information.

Gland: 1. A group of cells that secrete a substance for use in the body. For example, the thyroid gland. 2. A group of cells that removes materials from the circulation. For example, a lymph gland.

Haemophilus influenzae type B: Abbreviated as HIB, a bacterium capable of causing a range of diseases including ear infections, cellulitis (soft tissue infection), upper respiratory infections, pneumonia , and such serious invasive infections as meningitis with potential brain damage and epiglottitis with airway obstruction. It spreads by droplet through coughs and sneezing. Half of cases present as meningitis with fever, headache, and stiff neck. The remainder present as cellulitis, arthritis, or sepsis (bloodstream infection). About 5 percent of cases are fatal, Up to 20 percent of the survivors have permanent hearing loss. More than 90 percent of all HIB infections occur in children 5 years of age or younger-the peak attack rate is at 6 to 12 months of age. HIB causes 2 to 3 million cases of disease each year and about 450,000 deaths, the vast majority of them in developing countries today.
See the entire definition of Haemophilus influenzae type B

Hair loss : Hair loss is the thinning of hair on the scalp. The medical term for hair loss is alopecia . Alopecia can be temporary or permanent. The most common form of hair loss occurs gradually and is referred to as "androgenetic alopecia," meaning that a combination of hormones (androgens are male hormones) and heredity ( genetics ) is needed to develop the condition. Other types of hair loss include alopecia areata (patches of baldness that usually grow back), telogen effluvium (rapid shedding after childbirth, fever , or sudden weight loss); and traction alopecia (thinning from tight braids or ponytails).
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HBIG: Hepatitis B immune globulin, which contains antibodies to hepatitis B virus and offers prompt but short lived protection.

HBV: Hepatitis B virus. A virus which primarily causes inflammation of the liver. The hepatitis B virus can be transmitted in several ways including blood transfusion , needle sticks, body piercing and tattooing using unsterile instruments, dialysis , sexual and even less intimate close contact, and childbirth. Symptoms include fatigue, jaundice , nausea, vomiting, dark urine, and light stools. Diagnosis is by blood test(s).
See the entire definition of HBV

HCV: Hepatitis C virus.

HDV: Hepatitis D virus.

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Hepatitis: Inflammation of the liver from any cause.
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Hepatitis A: Inflammation of the liver caused by the hepatitis A virus (HAV). HAV is usually transmitted from person to person by food or drink that has been contaminated with the stool of a person with hepatitis A. This type of transmission is called "fecal-oral." The virus is more easily spread in areas where there are poor sanitary conditions or where good personal hygiene is not observed. In 2003 there were hepatitis A outbreaks in the US associated with eating raw or lightly cooked green onions (scallions). Casual contact, as in a school, office, or another work setting, does not spread the virus.
See the entire definition of Hepatitis A

Hepatitis B: Inflammation of the liver due to the hepatitis B virus (HBV), once thought to be passed only through blood products. It is now known that hepatitis B can also be transmitted via needle sticks, body piercing and tattooing using un sterilized instruments, the dialysis process, sexual and even less intimate close contact, and childbirth. Symptoms include fatigue, jaundice , nausea, vomiting, dark urine, light stools. Diagnosis is by blood test. Treatment is via anti-viral drugs and/or hepatitis B immunoglobulin (HBIG).
See the entire definition of Hepatitis B

Hepatitis C: Inflammation of the liver due to the hepatitis C virus (HCV), which is usually spread by blood transfusion, hemodialysis, and needle sticks. HCV causes most transfusion-associated hepatitis, and the damage it does to the liver can lead to cirrhosis and cancer. Transmission of the virus by sexual contact is rare. At least half of HCV patients develop chronic hepatitis C infection. Diagnosis is by blood test. Treatment is via anti-viral drugs. Chronic hepatitis C may be treated with interferon, sometimes in combination with anti-virals. There is no vaccine for hepatitis C. Previously known as non-A, non-B hepatitis.

Hepatitis C virus: A single-stranded RNA virus in the Flaviviridae family that causes hepatitis C. Abbreviated HCV. The HCV genome contains some 10,000 nucleotides and encodes a single polyprotein of 3,000 amino acids. HCV was discovered in 1989. Before that time, hepatitis C was referred to as non-A, non-B hepatitis.

Hepatitis D: Liver inflammation due to the hepatitis D virus (HDV), which only causes disease in patients who already have the hepatitis B virus. Transmission is via infected blood, needles, or sexual contact with an infected person. Symptoms are identical to those of hepatitis B. Chronic infection with HDV is currently treated with interferon, although it is not very successful. HDV infection can be prevented by the hepatitis B vaccine, and by avoiding activities that could lead to getting the virus.

Hepatocellular carcinoma: A tumor in which the cancer starts during adulthood in cells in the liver . Also called adult primary liver cancer.
See the entire definition of Hepatocellular carcinoma

High blood pressure : Also known as hypertension, high blood pressure is, by definition, a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90.
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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

Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.
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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.
See the entire definition of Human immunodeficiency virus

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.
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Hypothyroid: Deficiency of thyroid hormone which is normally made by the thyroid gland which is located in the front of the neck:

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

Immune response: Any reaction by the immune system.

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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.

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

Immunosuppressive: 1. Pertaining to immunosuppression , the suppression of the immune system .
2. An agent capable of suppressing the immune response .
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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.
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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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Inflammatory bowel disease: A group of chronic intestinal diseases characterized by inflammation of the bowel -- the large or small intestine. The most common types of inflammatory bowel disease (IBD) are ulcerative colitis and Crohn disease .
See the entire definition of Inflammatory bowel disease

Injure: To harm, hurt, or wound. The word injure may be in physical or emotional sense. Treadmill machines may injure anyone who gets on one. Sexual molestation injures children. From the Latin injuria meaning injury.

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.
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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.
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Kidney: One of a pair of organs located in the right and left side of the abdomen which clear "poisons" from the blood, regulate acid concentration and maintain water balance in the body by excreting urine. The kidneys are part of the urinary tract. The urine then passes through connecting tubes called "ureters" into the bladder. The bladder stores the urine until it is released during urination.


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Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.


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Liver biopsy : A procedure in which a small sample of the liver is removed for the diagnosis of abnormal liver conditions.
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Liver disease: Liver disease refers to any disorder of the liver. The liver is a large organ in the upper right abdomen that aids in digestion and removes waste products from the blood.
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Marker: A piece of DNA that lies on a chromosome so close to a gene that the marker and the gene are inherited together. A marker is thus an identifiable heritable spot on a chromosome. A marker can be an expressed region of DNA (a gene) or a segment of DNA with no known coding function. All that matters is that the marker can be detected and trailed.
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Marrow: The bone marrow.

Medical history: 1. In clinical medicine, the patient's past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed.
2. The history of medicine.

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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Methotrexate : A drug that acts as an antimetabolite and specifically as a folic acid antagonist that inhibits the synthesis of DNA , RNA , and protein .
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Microscope: An optical instrument that augments the power of the eye to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in 1628 borrowed from the Greek to combined micro-, small with skopein, to view. Although the first microscopes were simple microscopes, most (if not all) optical microscopes today are compound microscopes.

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."

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.
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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.

Needle stick: See: Needlestick injury.

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.

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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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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.

Osteoporosis: Thinning of the bones with reduction in bone mass due to depletion of calcium and bone protein . Osteoporosis predisposes a person to fractures, which are often slow to heal and heal poorly. It is more common in older adults, particularly post-menopausal women; in patients on steroids; and in those who take steroidal drugs. Unchecked osteoporosis can lead to changes in posture , physical abnormality (particularly the form of hunched back known colloquially as " dowager's hump "), and decreased mobility.
See the entire definition of Osteoporosis

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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Pertussis : Whooping cough, a communicable, potentially deadly illness characterized by fits of coughing followed by a noisy, "whooping" indrawn breath. It is caused by the bacteria Bordetella pertussis . The illness is most likely to affect young children, but sometimes appears in teenagers and adults, even those who have been previously immunized. Immunization with DPT (diphtheria-pertussis-tetanus) vaccine provides protection, although that immunity may wear off with age. When teenagers and adults get pertussis, it appears first as coughing spasms, and then a stubborn dry cough lasting up to eight weeks.
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Piercing: Using a sharp instrument, usually a needle, to make a temporary or permanent hole through an earlobe or other body part. Humans have practiced piercing for body decoration since prehistoric times. Unless it is performed using a sterile needle (preferably disposable), piercing can carry a risk of infection . A piercing should be kept clean; antibiotic cream may be applied if the area becomes inflamed.
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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.

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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Polyarteritis nodosa: An autoimmune disease (immune system attacking its own body) characterized by spontaneous inflammation of the arteries (arteritis) of the body. Because arteries are involved, the disease can affect any organ of the body, most commonly muscles, joints, intestines, nerves, kidneys, and skin.

Pregnant: The state of carrying a developing fetus within the body.
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Prevalence: The proportion of individuals in a population having a disease. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time.
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Progressive: Increasing in scope or severity. Advancing. Going forward. In medicine, a disease that is progressive is going from bad to worse.
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Prophylaxis: A measure taken for the prevention of a disease or condition.
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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.
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Quiescent: Marked by a state of inactivity, repose, or tranquillity. For example, a quiescent stem cell is a stem cell that is resting at the time but that might be stimulated later to divide and proliferate.
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Rash : Breaking out (eruption) of the skin. Medically, a rash is referred to as an exanthem.
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Rebound: Return of the original symptoms when maneuvers or treatment is discontinued.

RECOMBIVAX-HB: A vaccine against hepatitis B (hep B) to stimulate the body's immune system to produce antibodies against the hep B virus.

Recur: To occur again. To return. Any symptom (such as fatigue), any sign (such as a heart murmur), or any disease can recur.

Recurrent: Back again. A recurrent fever is a fever that has returned after an intermission: a recrudescent fever.

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.

Relapse: The return of signs and symptoms of a disease after a patient has enjoyed a remission . For example, after treatment a patient with cancer of the colon went into remission with no sign or symptom of the tumor, remained in remission for 4 years, but then suffered a relapse and had to be treated once again for colon cancer.
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Reproduction: The production of offspring. Reproduction need not be sexual. Yeast can reproduce by budding.
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Resistance: Opposition to something, or the ability to withstand it. For example, some forms of staphylococcus are resistant to treatment with antibiotics.
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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.
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RNA virus: A virus in which the genetic material is RNA. The RNA may be either double- or single-stranded.
See the entire definition of RNA virus

Safer sex: See: Safe sex.

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.
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Semen: The fluid that is released through the penis during orgasm. Semen is made up of fluid and of sperm. The fluid comes from the prostate, seminal vesicle and other sex glands. The sperm are manufactured in the testicles. The seminal fluid helps transport the sperm during orgasm. Seminal fluid contains sugar as an energy source for sperm.
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Seroconversion : The development of detectable antibodies in the blood directed against an infectious agent. It normally takes some time for antibodies to develop after the initial exposure to the agent.
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Spleen: An organ located in the upper left part of the abdomen near the stomach . The spleen produces lymphocytes ; it is the largest lymphatic organ in the body. The spleen also filters the blood, serves as a major reservoir for blood and destroys blood cells that are aged.
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Swallowing tube: Descriptive term for the esophagus. See: Esophagus.

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.

Tear: A drop of the salty secretion of the lacrimal glands which serves to moisten the conjunctiva and cornea.

Tetanus : An often fatal infectious disease caused by the bacteria Clostridium tetani (C. tetani) which usually enters the body through a puncture, cut, or open wound. Tetanus is characterized by profoundly painful spasms of muscles, including "locking" of the jaw so that the mouth cannot open (lockjaw). C. tetani releases a toxin that affects the motor nerves, (the nerves which stimulate the muscles).
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Therapy: The treatment of disease .
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Thyroid: 1. The thyroid gland . Also, pertaining to the thyroid gland. 2. A preparation of the thyroid gland used to treat hypothyroidism . 3. Shaped like a shield. (The thyroid gland was so-named by Thomas Wharton in 1656 because it was shaped like an ancient Greek shield.)
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Thyroid gland: A gland that makes and stores hormones that help regulate the heart rate, blood pressure, body temperature, and the rate at which food is converted into energy. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions ( metabolism ) in the body. Thyroid hormones also help children grow and develop.
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Toxin: One of a number of poisons produced by certain plants, animals, and bacteria.
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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.

Ultrasound: High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There is no convincing evidence for any danger from ultrasound during pregnancy.

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.
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Viral: Of or pertaining to a virus. For example, "My daughter has a viral rash ."
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Viral hepatitis: Viral hepatitis is liver inflammation caused by viruses. Specific hepatitis viruses have been labeled A, B, C, D, E, F, and G. While other viruses can also cause hepatitis, their primary target is not the liver.

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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.
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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.

Vital: Necessary to maintain life. Breathing is a vital function.

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

Weight loss: Weight loss is a decrease in body weight resulting from either voluntary (diet, exercise) or involuntary (illness) circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight loss include the weight loss associated with cancer, malabsorption (such as from chronic diarrheal illnesses ), and chronic inflammation (such as with rheumatoid arthritis).

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Hepatitis B

What is thrombocytopenia?

Thrombocytopenia is a lower than normal number of platelets in the blood.

Platelets are one of the components of the blood along with white and red blood cells. Platelets play an important role in clotting and bleeding. Platelets are made in the bone marrow similar to other cells in the blood such as, white blood cells and red blood cells. Platelets originate from megakaryocytes which are large cells found in the bone marrow. The fragments of these megakaryocytes are platelets that are released into the blood stream. The circulating platelets make up about two third of the platelets that are released from the bone marrow. The other one third is typically stored (sequestered) in the spleen.

Platelets, in general, have a brief 7 to 10 days life in the blood, after which they are removed from the blood circulation. The number of platelets in the blood is referred to as the platelet count and is normally betw...

Read the Thrombocytopenia (Low Platelet Count) article »











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