Thrombocytopenia (Low Platelet Count) Glossary of Terms

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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).

Acetaminophen: A pain reliever and fever reducer. Brand name: Tylenol. The exact mechanism of action of acetaminophen is not known. Acetaminophen relieves pain by elevating the pain threshold (that is, by requiring a greater amount of pain to develop before it is felt by a person). Acetaminophen reduces fever through its action on the heat-regulating center (the "thermostat") of the brain. Generic is available.

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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Agranulocytosis: A marked decrease in the number of granulocytes. Granulocytes are a type of white blood cell filled with microscopic granules that are little sacs containing enzymes that digest microorganisms.
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Alcohol abuse: Use of alcoholic beverages to excess, either on individual occasions ("binge drinking") or as a regular practice. For some individuals-children or pregnant women, for example-almost any amount of alcohol use may be legally considered "alcohol abuse," depending on local laws. Heavy alcohol abuse can cause physical damage and death.

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.
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Aplastic anemia: Anemia due to failure of the bone marrow to produce blood cells, including red and white blood cells as well as platelets. Aplastic anemia frequently occurs without a known cause. Known causes include exposure to chemicals (benzene, toluene in glues, insecticides, solvents), drugs (chemotherapy, gold, seizure medications, antibiotics, and others), viruses (HIV, Epstein-Barr), radiation, immune conditions (systemic lupus erythematosus, rheumatoid arthritis), pregnancy, paroxysmal nocturnal hemoglobinuria, and inherited disorders (Fanconi's anemia).
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Artificial heart: A manmade heart. An artificial heart was temporarily implanted in 1969 by Denton Cooley in Houston, Texas. Complete replacement of the heart by an artificial heart was done in 1982 by William DeVries at Salt Lake City, Utah. Barney Clark was the patient.

Autoimmune: Pertaining to autoimmunity, a misdirected immune response that occurs when the immune system goes awry and attacks the body itself.
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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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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 clot: Blood that has been converted from a liquid to a solid state. Also called a thrombus.
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Blood count: The calculated number of white or red blood cells (WBCs or RBCs) in a cubic millimeter of blood.

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.

Bone marrow biopsy: The removal of a sample of bone marrow and a small amount of bone (usually from the hip) through a large needle. Two samples are taken. The first is bone marrow by aspiration (suction with a syringe). The second sample is a core biopsy to obtain bone marrow together with bone fibers. After the needle is removed, this solid sample is pushed out of the needle with a wire. Both samples are examined under a microscope to see the cells and architecture of the bone marrow.

Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
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CBC: A commonly used abbreviation in medicine that stands for complete blood count, a set values of the cellular (formed elements) of blood. These measurements are generally determined by specially designed machines that analyze the different components of blood in less than a minute.
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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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Chemotherapy: 1. In the original sense, a chemical that binds to and specifically kills microbes or tumor cells. The term chemotherapy was coined in this regard by Paul Ehrlich (1854-1915).
2. In oncology, drug therapy for cancer. Also called "chemo" for short.
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Chickenpox: A highly infectious viral disease also known medically as varicella -- in many countries, this disease is always called "varicella" -- that causes a blister-like rash, itching, fatigue and fever. The rash crops up first on the face and trunk and can spread over the entire body resulting in 250 to 500 itchy blisters.

Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
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Circulation: The movement of fluid in a regular or circuitous course. Although the noun "circulation" does not necessarily refer to the circulation of the blood, for all practical purposes today it does. Heart failure is an example of a problem with the circulation.

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.

Coagulation: In medicine, the clotting of blood. The process by which the blood clots to form solid masses, or clots.
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Complete blood count: A set values of the cellular (formed elements) of blood. These measurements are generally determined by specially designed machines that analyze the different components of blood in less than a minute.
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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.

Congenital: Present at birth. A condition that is congenital is one that is present at birth. There are numerous uses of "congenital" in medicine. There are, for example, congenital abnormalities. (For more examples, see below.)
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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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Diarrhea: A familiar phenomenon with unusually frequent or unusually liquid bowel movements, excessive watery evacuations of fecal material. The opposite of constipation. The word "diarrhea" with its odd spelling is a near steal from the Greek "diarrhoia" meaning "a flowing through." Plato and Aristotle may have had diarrhoia while today we have diarrhea. There are myriad infectious and noninfectious causes of diarrhea.
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EBV: Epstein-Barr virus, best known as the cause of infectious mononucleosis ("mono").
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Enlarged spleen: Splenomegaly, or an enlargement of the spleen. This condition can occur with different medical conditions ranging from blood disorders to infections and certain forms of cancer.
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Enoxaparin: A low-molecular-weight version of heparin which acts like heparin as an anticoagulant (anti-clotting) medication. Enoxaparin is used to prevent thromboembolic complications (clots that travel from their site of origin through the blood stream to clog up another vessel). Enoxaparin is also used in the early treatment of blood clots in the lungs (pulmonary embolisms).

Enzymes: Proteins that act as a catalysts in mediating and speeding a specific chemical reaction.
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Epstein-Barr virus: A virus, abbreviated EBV, best known as the cause of infectious mononucleosis ("mono").
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Escherichia coli: Full term for E. coli, the colon bacillus.

Essential: 1. Something that cannot be done without.
2. Required in the diet, because the body cannot make it. As in an essential amino acid or an essential fatty acid.
3. Idiopathic. As in essential hypertension. "Essential" is a hallowed term meaning "We don't know the cause."

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.

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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Hemoglobin: The oxygen-carrying pigment and predominant protein in the red blood cells. Hemoglobin forms an unstable, reversible bond with oxygen. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced state it is called deoxyhemoglobin and is purple-blue.
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Hemolytic: Referring to hemolysis, the destruction of red blood cells which leads to the release of hemoglobin from within the red blood cells into the blood plasma.
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Hemolytic anemia: Anemia due to the destruction (rather than underproduction) of red blood cells.

Hemolytic uremic syndrome: A condition characterized by the breakup of red blood cells (hemolysis) and kidney failure. There is clumping of platelets (the blood cells responsible for clotting) within the kidney's small blood vessels with resultant ischemia (reduced blood flow) leading to the kidney failure. The partial blockage of the blood vessels also leads to the destruction of red blood cells (hemolysis). Platelets are also decreased which can cause bleeding problems.
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Heparin: An anticoagulant (anti-clotting) medication. Heparin is useful in preventing thromboembolic complications (clots that travel from their site of origin through the blood stream to clog up another vessel). Heparin is also used in the early treatment of blood clots in the lungs (pulmonary embolisms).

Heparin-induced thrombocytopenia: Low blood platelet count as a result of the medication heparin. Heparin is used to treat and prevent abnormal blood clotting. Heparin-induced thrombocytopenia can be mild or serious and fatal.

Hepatitis: Inflammation of the liver from any cause.
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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.

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).
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Idiopathic: Of unknown cause. Any disease that is of uncertain or unknown origin may be termed idiopathic. For example, acute idiopathic polyneuritis, diffuse idiopathic skeletal hyperostosis, idiopathic pulmonary fibrosis, idiopathic scoliosis, etc.
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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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Immunoglobulin: A protein produced by plasma cells and lymphocytes and characteristic of these types of cells. Immunoglobulins play an essential role in the body's immune system. They attach to foreign substances, such as bacteria, and assist in destroying them. Immunoglobulin is abbreviated Ig. The classes of immunoglobulins are termed immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin D (IgD) and immunoglobulin E (IgE).

Internal medicine: A medical specialty dedicated to the diagnosis and medical treatment of adults. A physician who specializes in internal medicine is referred to as an internist. A minimum of seven years of medical school and postgraduate training are focused on learning the prevention, diagnosis, and treatment of diseases of adults. Subspecialties of internal medicine include allergy and immunology, cardiology (heart), endocrinology (hormone disorders), hematology (blood disorders), infectious diseases, gastroenterology (diseases of the gut), nephrology (kidney diseases), oncology (cancer), pulmonology (lung disorders), and rheumatology (arthritis and musculoskeletal disorders).

ITP: 1. Idiopathic thrombocytopenic purpura. (Original use.)
2. Immune thrombocytopenic purpura. (Newer use).
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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.

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."

Leukemia: Cancer of the blood cells. The growth and development of the blood cells are abnormal. Strictly speaking, leukemia should refer only to cancer of the white blood cells (the leukocytes) but in practice it can apply to malignancy of any cellular element in the blood or bone marrow, as in red cell leukemia (erythroleukemia).
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Leukopenia: Lower than the normal amount of white blood cells.

Liter: A metric measure of capacity that, by definition, is equal to the volume of a kilogram of water at 4 degrees centigrade and at standard atmospheric pressure of 760 millimeters of mercury.

• Metric equivalents -- There are 1000 cubic centimeters or 1 cubic decimeter in 1 liter.
• U.S. equivalent -- A liter is a little more than a quart (1.057 U.S. liquid quarts).

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.

Low platelets: see thrombocytopenia.

Lupus: A chronic inflammatory condition caused by an autoimmune disease. An autoimmune disease occurs when the body's tissues are attacked by its own immune system. Patients with lupus have unusual antibodies in their blood that are targeted against their own body tissues.
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Lymphoma: Tumor of the lymphoid tissue. Diagnosis is by biopsy. Treatment may be chemotherapy, radiation, surgery, or medication, depending on the age of the patient and type of tumor.

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.

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.

MPH: Master of Public Health (a master's degree in this field of medicine).

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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Neonatal: Pertaining to the newborn period which, by convention, is the first four weeks after birth.

Normal range: By convention, the normal range for whatever (a particular test, condition, symptom, behavior, etc.) is set to cover ninety-five percent (95%) of all values from the general population. Five percent (5%) of results consequently fall outside the normal range. Values that prove normal can therefore sometimes be outside the normal range.
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Petechiae: Pinpoint flat round red spots under the skin surface caused by intradermal hemorrhage (bleeding into the skin). Petechiae are red because they contain red blood that has leaked from the capillaries into the skin. Petechiae are quite tiny (less than 3 millimeters in diameter) and do not blanch when pressed upon.
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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.

Plasmapheresis: A procedure designed to deplete the body of blood plasma (the liquid part of the blood) without depleting the body of its blood cells. Whole blood is removed from the body, the plasma is separated from the cells, the cells are suspended in saline, a plasma substitute or donor plasma), and the reconstituted solution may be returned to the patient. The procedure is used to remove excess antibodies from the blood in lupus, multiple sclerosis, multiple myeloma, etc. Plasmapheresis carries with it the same risks as any intravenous procedure. The risk of infection increases with the use of donor plasma, which may carry viral particles despite screening procedures. The procedure is done in a clinic or hospital.

Platelet: An irregular, disc-shaped element in the blood that assists in blood clotting. During normal blood clotting, the platelets clump together (aggregate). Although platelets are often classed as blood cells, they are actually fragments of large bone marrow cells called megakaryocytes.

Platelet count: The calculated number of platelets in a volume of blood, usually expressed as platelets per cubic millimeter (cmm) of whole blood. Platelets are the smallest cell-like structures in the blood and are important for blood clotting and plugging damaged blood vessels. Platelet counts are usually done by laboratory machines that also count other blood elements such as the white and red cells. They can also be counted by use of a microscope. Normal platelet counts are in the range of 150,000 to 400,000 per microliter (or 150 - 400 x 10⁹ per liter). These values many vary slightly between different laboratories.

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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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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Purpura: 1. A hemorrhagic area in the skin. The area of bleeding within the skin, by definition, is greater than 3 millimeters in diameter. The appearance of the purpura depends on age of the lesion. Early purpura is red and becomes darker, then purple, and brown-yellow as it fades. Purpura does not blanch when touched.
2. A condition characterized by purpura such as immune thrombocytopenic purpura and Schonlein-Henoch purpura.

Quinine: The original antimalarial agent, quinine took its name from the Peruvian Indian word "kina" meaning "bark of the tree" referring to the cinchona tree. From this tree, quinine was first obtained. The Peruvian Indians called it "the fever tree."
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Radiation: 1. Rays of energy. Gamma rays and X-rays are two of the types of energy waves often used in medicine. 2. The use of energy waves to diagnose or treat disease. See also: Irradiation.

Rash: Breaking out (eruption) of the skin. Medically, a rash is referred to as an exanthem.

Red blood cell: The blood cell that carries oxygen. Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide). Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cell its red color (and name).
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Red blood cells: The blood cells that carry oxygen. Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide). Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cells their red color (and their name).
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Red cell count: The number of red blood cells (RBCs) in a volume of blood. The normal range varies slightly between laboratories but is generally between 4.2 - 5.9 million cells/cmm. This can also be referred to as the erythrocyte count and can be expressed in international units as 4.2 - 5.9 x 10¹² cells per liter.

Red cells: Short for red blood cells, the oxygen/carbon dioxide carrying cells in blood. Also known acronymically as RBC's, red corpuscles or erythrocytes (literally, red hollow vessels).

Rupture: A break or tear in any organ (such as the spleen) or soft tissue (such as the achilles tendon). Rupture of the appendix is more likely among uninsured and minority children when they develop appendicitis.

Sepsis: Commonly called a "blood stream infection." The presence of bacteria (bacteremia) or other infectious organisms or their toxins in the blood (septicemia) or in other tissue of the body. Sepsis may be associated with clinical symptoms of systemic (bodywide) illness, such as fever, chills, malaise (generally feeling "rotten"), low blood pressure, and mental status changes. Sepsis can be a serious situation, a life threatening disease calling for urgent and comprehensive care.
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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.

Splenectomy: An operation to remove the spleen.

Splenomegaly: Enlargement of the spleen.
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Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.
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Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease.
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Systemic: Affecting the entire body. A systemic disease such as diabetes can affect the whole body. Systemic chemotherapy employs drugs that travel through the bloodstream and reach and affect cells all over the body.

Thrombocyte: A platelet. Crucial to normal blood clotting. Although platelets are sometimes classed as blood cells, they are not. They are fragments of a large cell called a megakaryocyte (literally, a large cell).

Thrombocytopenia: A low platelet count. Platelets are irregular, disc-shaped element in the blood that assists in blood clotting. thrombocytopenia can arise due to decreased production of platelets in the bone marrow or increased breakdown of platelets in the bloodstream, spleen, or liver. Thrombocytopenia is characterized by easy bruising and increased bleeding.

Thrombocytosis: See thrombocythemia.

Toxicity: The degree to which a substance can harm humans or animals.
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Transfusion: The transfer of blood or blood products from one person (the donor) into another person (the recipient's) bloodstream. In most situations, this is done as a lifesaving maneuver to replace blood cells or blood products lost through severe bleeding. Transfusion of your own blood (autologous) is the safest method but requires planning ahead and not all patients are eligible. Directed donor blood allows the patient to receive blood from known donors. Volunteer donor blood is usually most readily available and, when properly tested has a low incidence of adverse events.
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Vasculitis: Plural: vasculitides. A general term for a group of diseases that feature inflammation of the blood vessels. Each of these diseases is defined by characteristic distributions of blood vessel involvement, patterns of organ involvement, and laboratory test abnormalities. The causes of these vasculitis diseases are usually not known, but immune system abnormality is a common feature.
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Vessel: A tube in the body that carries fluids: blood vessels or lymph vessels.

Viral: Of or pertaining to a virus. For example, "My daughter has a viral rash."

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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Vitamin B12: A vitamin important for the normal formation of red blood cells and the health of the nerve tissues. Undetected and untreated vitamin B12 deficiency can lead to anemia and permanent nerve and brain damage.
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White blood cell: One of the cells the body makes to help fight infections. There are several types of white blood cells (leukocytes). The two most common types are the lymphocytes and neutrophils (also called polymorphonuclear leukocytes, PMNs, or "polys").
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