Click on the alphabet and there you go!

E

Ear: The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain.

Ear canal, self-cleaning: Most of the time the ear canals are self-cleaning, that is, there is a slow and orderly migration of ear canal skin from the eardrum to the outer opening. Old earwax is constantly being transported from the deeper areas of the ear canal to the opening where it usually dries, flakes, and falls out.

Ear cleaning (by a doctor): When so much wax accumulates that it blocks the ear canal (and hearing), your physician may have to wash it out, vacuum it, or remove it with special instruments. Alternatively, your physician may prescribe ear drops what are designed to soften the wax (such as Cerumenex).

Ear cleaning (yourself): Never put anything smaller than your elbow in your ear! Wax is not formed in the deep part of the ear canal near the eardrum, but only in the outer part of the canal. So when a patient has wax pushed up against the eardrum, it is often because he has been probing his ear with such things as cotton-tipped swabs (such as Q-Tips), bobby pins, or twisted napkin corners. Such objects only serve as ramrods to push the wax in deeper. Also, the skin of the ear canal and the eardrum is very thin, fragile and easily injured. The ear canal is more prone to infection after it has been whipped clean of the "good" coating type wax. In addition, we have seen many perforated eardrums as a result of these efforts.

Ear, low-set: A minor anomaly involving an ear situated down below its normal location. Technically, the ear is low-set when the helix (of the ear) meets the cranium at a level below that of a horizontal plane through both inner canthi (the inside corners of the eyes). The presence of 2 or more minor anomalies in a child increases the probability that the child has a major malformation.

Ear, malrotated: See Ear, slanted.

Ear pit: Tiny pit in front of the ear: preauricular pit. A minor anomaly of no great consequence in itself. More common in blacks than whites and in females than males. Can recur in families. The presence of 2 or more minor anomalies in a child increases the probability that the child has a major malformation.

Ear puncture: Puncture of the ear drum may be due to an accident for example when something is stuck into the ear. Or it may be due to fluid pressure in the middle ear. Today the ear drum is occasionally punctured on purpose with surgery. A surgically placed tiny incision (a myringotomy) is made in the eardrum. Any fluid, usually thickened secretions, is removed and an ear tube may be inserted.

Ear ringing: Together with other abnormal ear noises, ear ringing is medically called tinnitis. Tinnitus can arise in any of the four sections of the ear: the outer ear, the middle ear, the inner ear, and the brain. If tinnitus persists and its cause is unknown, a hearing test (audiogram) should be done. Measures can be taken to lessen the intensity of tinnitus.

Ear, slanted: An ear that is slanted more than usual. Technically, an ear is slanted when the angle of the slope of the auricle is more than 15 degrees from the perpendicular. Also called a malrotated ear Considered a minor anomaly. The presence of 2 or more minor anomalies in a child increases the probability that the child has a major malformation.

Ear tag: Common minor anomaly, a rudimentary tag of ear tissue, often containing a core cartilage, usually located just in front of the ear (auricle). Therefore also called preauricular tag. The presence of 2 or more minor anomalies in a child increases the probability that the child has a major malformation.

Ear tubes: Formally known as tympanostomy tubes, ear tubes are small plastic tubes inserted into the eardrum (the tympanum) to keep the middle ear aerated for a prolonged period of time. To put the tubes in place, a myringotomy (a surgically placed tiny incision in the eardrum) is done. Any fluid, usually thickened secretions, will be removed. The ear tubes usually remain in place for 6 months to several years. Water should not be allowed to enter the ear canal while the tubes are in place. Eventually, they will move out of the eardrum (extrude) and fall into the ear canal. The doctor may remove the tube during a routine future office visit or it may simply fall out of the ear without the child realizing it.

Ear wax: The ear canal is shaped somewhat like an hourglass. The skin on the outer part of the canal has special glands that produce earwax. The purpose of this natural wax is to repel water and to trap dust and sand particles. Usually a small amount of wax accumulates, and then dries up and falls out of the ear canal caring with it unwanted particles. Ear wax is helpful in normal amounts and serves to coat the skin of the ear canal where it acts as a temporary water repellent. The absence of ear wax may result in dry, itchy ears, and even infection.

Eardrum: The tympanic membrane of the ear.

EBV: The Epstein-Barr virus which can cause infectious mononucleosis ("mono").

ECG: Abbreviation for electrocardiogram. Abbreviation for electrocardiogram. The K is from "kardio" (in German).

Ecchymosis: The skin discoloration caused by a bruise (contusion).

Ecchymotic: Characterized by ecchymosis.

Echocardiography: Echocardiography is a diagnostic test which uses ultrasound waves to make images of the heart chambers, valves and surrounding structures. It can measure cardiac output and is a sensitive test for inflammation around the heart (pericarditis). It can also be used to detect abnormal anatomy or infections of the heart valves.

Echovirus: One of a group of viruses.

E. coli: Short for Escherichia coli, the colon bacillus, a bacterium that normally resides in the human colon. E. coli has been studied intensively in genetics and molecular and cell biology because of its availability, its small genome size, its normal lack of pathogenicity (disease-causing ability), and its ease of growth in the laboratory.

Ecogenetics: The interaction of genetics with the environment. The genetic disease PKU (phenylketonuria) provides an illustration of ecogenetics. Persons with PKU lack an enzyme to process an amino acid (phenylalanine) and so require a special environment: a diet low in phenylalanine.

Ectopia cordis: A type of birth defect resulting in an abnormal location of the heart. (Most often, in individuals with ectopia cordis, the heart protrudes outside the chest.)

Ectopic: In the wrong place. An ectopic kidney, for example, is one that is not in the usual location.

Ectopic pregnancy: A pregnancy that is not in the usual place and is located outside the inner lining of the uterus. A fertilized egg settles and grows in any location other than the inner lining of the uterus. The vast majority of ectopic pregnancies occur in the fallopian tube (95%), however, they can occur in other locations, such as the ovary, cervix, and abdominal cavity. An ectopic pregnancy occurs in about 1 in 60 pregnancies. A major concern with an ectopic pregnancy is internal bleeding. If there is any doubt, seek medical attention promptly.

Ectopic pregnancy, symptoms of: Symptoms of an ectopic pregnancy can often be vague and include vaginal bleeding, abdominal or pelvic pain (usually stronger on one side),shoulder pain, weakness, or dizziness. Weakness, dizziness, and a sense of passing out upon standing can represent serious internal bleeding, requiring immediate medical attention.

Eczema: A particular reaction pattern of the skin, the most common type in children being atopic (allergic) dermatitis.

Edema: Edema is the swelling of soft tissues as a result of excess water accumulation. It is often more prominent in the lower legs and feet toward the end of the day as a result of pooling of fluid from the upright position maintained during the day. Upon awakening from sleeping, patients can have swelling around the eyes referred to as "periorbital edema."

Edema, hereditary angioneurotic: A genetic form of angioedema. (Angioedema is also referred to as Quinke’s disease.) Persons with it are born lacking an inhibitor protein (called C1 esterase inhibitor) that normally prevents activation of a cascade of proteins leading to the swelling of angioedema. Patients can develop recurrent attacks of swollen tissues, pain in the abdomen, and swelling of the voice box (larynx) which can compromise breathing. The diagnosis is suspected with a history of recurrent angioedema. It is confirmed by finding abnormally low levels of C1 esterase inhibitor in the blood. Treatment options include antihistamines and male steroids (androgens) that can also prevent the recurrent attacks. Also called hereditary angioedema.

Edwards syndrome: This is trisomy 18 syndrome. There are three instead of the normal two chromosomes #18. Children with this condition have multiple malformations and mental retardation due to the extra chromosome #18. The children characteristically have low birth weight, small head (microcephaly), small jaw (micrognathia), malformations of the heart and kidneys, clenched fists with abnormal finger positioning, and malformed feet. The mental retardation is profound with the IQ too low to edven test. Nineteen out of 20 (95%) of these children die before their first birthday. The condition is named after the British physician and geneticist John Edwards who discovered the extra chromosome in 1960.

EGD (esophagogastroduodenoscopy): A procedure that enables the examiner (usually a gastroenterologist ) to examine the esophagus ( swallowing tube), stomach, and duodenum ( first portion of small bowel ) using a thin flexible tube (a "scope") that can be looked through or seen on a TV monitor. Also called upper endoscopy

Egg: Ovum (plural: ova).

Ehrlichiosis: An acute (abrupt-onset) disease (first reported in humans in 1986) due to infection by the rickettsial agent, Ehrlichia canis. The brown dog tick, is the common vector (carrier). The disease is similar to Rocky Mountain spotted fever with high fever, headache, malaise, and muscle pain but no rash. Named for the great German Nobel Prize winning physician and bacteriologist Paul Ehrlich (1854-1915).

Ejaculation: Ejection of sperm and seminal fluid.

Elbow: The joint where three long bones meet in the middle portion of the arm. The bone of the upper arm (humerus) meets the inner bone of the forearm (ulna) and the outer bone of the forearm (radius) to form a hinge joint. The radius and ulna also meet in the elbow to allow for rotation of the forearm. The elbow functions to move the arm like a hinge (forward and backward) and in rotation (twisting outwards and inwards). The biceps muscle is the major muscle that flexes the elbow hinge. The triceps muscle is the major muscle that extends the elbow hinge. The outer bone of the elbow is the lateral epicondyle and is a part of the humerus bone. Tendons are attach to this area which can be injured, causing inflammation or tendinitis (lateral epicondylitis, or "tennis elbow"). The inner portion of the elbow is a bony prominence called the medial epicondyle. Additional tendons from the muscles attach here and can be injured, causing medial epicondylitis, "golfer’s elbow."

Elbow, arthritis of the: Inflammation (arthritis) of the elbow joint can be due to many systemic forms of arthritis, including rheumatoid arthritis, gouty arthritis, psoriatic arthritis, ankylosing spondylitis, and Reiter’s disease. Generally, they are associated with signs of inflammation of the elbow joint, including heat, warmth, swelling, pain, tenderness, and decreased range of motion. Range of motion of the elbow is decreased with arthritis of the elbow because the swollen joint impedes the range of motion

Elbow bursitis: At the tip of the elbow (the olecranon area), there is a bursa, a fluid-filled sac that functions as a gliding surface to reduce friction with motion. This bursa is known as the olecranon bursa. Because of its location, the olecranon bursa is subject to trauma, ranging from simple repetitive weight bearing while leaning, to banging in a fall. This trauma can cause a common, aseptic form of bursitis (olecranon bursitis) with varying degrees of swelling, warmth, tenderness and redness in the area overlying the point of the elbow.

Elbow bursitis, treatment of: If non-infectious, elbow bursitis treatment includes rest, ice, and medications for inflammation and pain. Infectious bursitis is treated with antibiotics, aspiration, and surgery.

Elbow, cellulitis of the: Inflammation of the skin around the elbow due to infection (cellulitis) commonly occurs as a result of abrasions or puncture wounds permitting bacteria on the surface of the skin to invade the deeper layers of the skin. This causes inflamed skin characterized by heat, redness, warmth, and swelling. The most common bacteria that cause cellulitis include Staphylococcus ("Staph") and Streptococcus ("Streop"). One can have an associated low-grade fever. Cellulitis generally requires antibiotic treatment, either orally or intravenously. Heat application can help in the healing process.

Elbow, golfer’s: The inner portion of the elbow is a bony prominence called the medial epicondyle. Tendons from the muscles attach here and can be injured, causing medial epicondylitis. To those who play the ancient Scottish sport, this is "golfer’s elbow."

Elbow pain: The elbow joint is quite complex because it is the area of union of three long bones. Elbow pain has many causes including arthritis and bursitis. Tendinitis can affect the inner or outer elbow; the treatment includes ice, rest, and medication for inflammation. Bacteria can also infect the skin of the scraped (abraded) elbow. The "funny bone" nerve can be irritated at the elbow to cause numbness and tingling of the little and ring fingers.

Elbow, tennis: The outer bone of the elbow is the lateral epicondyle and is a part of the humerus bone. Tendons are attach to this area which can be injured, causing inflammation or tendinitis (lateral epicondylitis). This is known to tennis players as "tennis elbow".

Electrocardiogram: A recording of the electrical activity of the heart. To take a specific situation, the initial diagnosis of a heart attack is usually made by a combination of clinical symptoms and characteristic electrocardiogram (EKG) changes. The EKG can detect areas of muscle ischemia (muscle deprived of oxygen) and/or dead tissue in the heart.

Electrodesiccation: Use of an electric current to destroy cancerous tissue and control bleeding.

Electrolarynx: A battery-operated instrument that makes a humming sound to help laryngectomees talk.

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.)

Electron microscope: Microscope that uses electron beams rather than light beams to provide a magnified image of tiny particles. The electron microscope is more powerful than the light microscope and in some diseases can provide detailed images that lead to the diagnosis of specific conditions.

Electron microscopy (EM): A microscope in which electron beams replaceslight rays to form the image. EM has its pluses (greater magnification and resolution than optical microscopes) and minuses (you are not really "seeing" objects, but rather their electron densities, and artefacts often abound). Despite such limitations, EM has greatly extended the powers of the microscope.

Electrophoresis: Method used in clinical and research laboratories for separating molecules according their size and electrical charge. Electrophoresis is used to separate large molecules (such as DNA fragments or proteins) from a mixture of molecules. An electric current is passed through a medium containing the mixture of molecules. Each kind of molecule travels through the medium at a different rate, depending on its electrical charge and molecular size. Separation of the molecules is based on these differences. Although many substances including starch gels and paper have historically served as media for electrophoresis, agarose and acrylamide gels are the media commonly used for electrophoresis of proteins and nucleic acids.

Elliptocytosis: Hematologic disorder characterized by elliptically shaped red blood cells (elliptocytosis) with variable breakup of red cells (hemolysis) and varying degrees of anemia. Inherited as a dominant trait. Due to mutation (change) in one of the genes encoding proteins of the red cell membrane skeleton. In 1956 Newton Morton brilliantly showed that there were at least 2 forms of elliptocytosis, one form unlinked to the Rh blood group and another form linked to Rh (now known to be on chromosome 1). The Rh-linked form, (EL1) in chromosome region 1p34.2-p33 is due to a mutation in erythrocyte membrane protein 4.1. Forms of elliptocytosis not linked to Rh are due to mutations in the alpha-spectrin gene, the beta-spectrin gene, or the band 3 gene.

EM: Electron microscopy . Or electron microscopy. Viral particles may be detectable by EM.

Embryo: The organism from fertilization to, in humans, the beginning of the third month of pregnancy. After that point in time, it is termed a fetus.

Embolization: A treatment that clogs small blood vessels and blocks the flow of blood, such as to a tumor.

Embolus: A blockage or plug which is obstructing a blood vessel. Examples of emboli are a detached blood clot, a clump of bacteria, or other foreign material, such as air.

Emergency Supplies Kit: You and your family can cope best by preparing for disaster before it strikes. One way to prepare is by assembling a Disaster Supplies Kit. Once disaster hits, you won’t have time to shop or search for supplies. But if you’ve gathered supplies in advance, your family can endure an evacuation or home confinement. For useful information, see the MedicineNet site on YOUR FAMILY DISASTER SUPPLIES KIT.

Emesis: Vomiting.

Emphysema: A lung condition featuring an abnormal accumulation of air in the tissue of the lung called alveoli (the lung's many tiny air sacs).

Empiric risk: The chance that a disease will occur in a family based upon experience (past history, medical records, etc.) rather than theory.

Empyema: Pus in the pleural space (space between the outer surface of the lung and the chest wall). Empyema typically is a result of a serious bacterial infection.

Encephalitis: Inflammation of the brain. Encopresis: Inability to control the elimination of stool (fecal incontinence).

Encapsulated: Confined to a specific area; the tumor remains in a compact form.

Encopresis: Inability to control the elimination of stool (fecal incontinence).

Endemic: Continuously present (as, for example, with malaria in some areas or illicit drugs in a neighborhood). The opposite of epidemic (a sudden outbreak).

Endemic typhus: Murine typhus, an acute infectious disease with fever, headache, and rash, all quite similar to, but milder than, epidemic typhus, caused by a related microoganism, Rickettsia typhi (mooseri), transmitted to humans by rat fleas (Xenopsylla cheopis). The animal reservoir includes rats, mice and other rodents. Murine typhus occurs sporadically worldwide but is more prevalent in congested rat-infested urban areas. Also known as rat-flea typhus or urban typhus of Malaya.

Endocardium: The lining of the interior surface of the heart chambers. Consists of a layer of endothelial cells and an underlying layer of connective tissue.

Endocervical curettage: The removal of tissue from the inside of the cervix using a spoon-shaped instrument called a curette.

Endocrinology: The study of the medical aspects of hormones and their associated diseases and conditions. (An endocrinologist is a doctor that specializes in the management of hormone conditions).

Endogenous: Inside. For example, endogenous cholesterol is cholesterol that is made inside the body and is not in the diet.

Endometriosis: A benign condition in which tissue that looks like endometrial tissue grows in abnormal places, most often in the abdomen. Although most women with endometriosis have no symptoms, pelvic pain during menstruation or ovulation can be a symptom of endometriosis. Endometriosis can also be suspected by a doctor during a physical examination and confirmed by surgery, usually laparoscopy. Treatment opptions include medication for pain, hormone therapy, and surgery.

Endometritis: Inflammation of the endometrium. The endometrium is the inner layer of the womb (uterus).

Endometrium: The inner layer of the uterus.

Endonuclease: An enzyme that cleaves a nucleic acid (DNA oor RNA) at specific internal sites in the nucleotide base sequence.

Endoscope: A flexible, lighted instrument used to examine organs such as the throat or esophagus.

Endoscopy: A procedure in which the doctor looks inside the body through a lighted tube called an endoscope.

Endoscopic Retrograde Cholangio-Pancreatography (ERCP): A diagnostic procedure to examine diseases of the liver, bile ducts and pancreas. It is uncomfortable but not painful, is performed under intravenous sedation, usually without general anesthesia, and has a low incidence of complications. ERCP provides important information unobtainable by other diagnostic means. Therapeutic measures can often be take at the time of ERCP to remove stones in the bile ducts or to relieve obstructions of the bile ducts.

Endoscopy, upper: A procedure that enables the examiner (usually a gastroenterologist ) to examine the esophagus (swallowing tube ), stomach, and duodenum ( first portion of small bowel ) using a thin flexible tube (a "scope") that can be looked through or seen on a TV monitor. Also known as esophagogastroduodenoscopy or EGD.

Endothelium: The layer of cells lining the closed internal spaces of the body such as the blood vessels and lymphatic vessels (that convey the lymph, a milky fluid). By contrast, the epithelium is the outside layer of cells that covers all the free, open surfaces of the body including the skin, and mucous membranes that communicate with the outside of the body.

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

Enophthalmos: Sunken eyeball.

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).

E.N.T.: Ear, Nose, and Throat. An E.N.T. physician is specialist concerned with the treatment of disorders of the head and neck including particularly the ears, nose, and throat.

Enteric: Of or relating to the small intestine.

Enteric-coated: Coated with a material that permits transit through the stomach to the small intestine before the medication is released.

Enteritis, Crohn’s: Crohn’s disease involving only the small intestine. Crohn’s disease is a chronic inflammatory disease of the intestine primarily affecting the small and large intestines but which can occur anywhere in the digestive system between the mouth and the anus. Named after Burrill Crohn who described the disease in 1932. The disease usually affects persons in their teens or early twenties. It tends to be a chronic, recurrent condition with periods of remission and exacerbation. In the early stages, Crohn’s disease causes small scattered shallow crater-like areas (erosions) called apthous ulcers in the inner surface of the bowel. With time, deeper and larger ulcers develop, causing scarring and stiffness of the bowel and the bowel becomes increasingly narrowed, leading to obstruction. Deep ulcers can puncture holes in the bowel wall, leading to infection in the abdominal cavity (peritonitis) and in adjacent organs Abdominal pain, diarrhea, vomiting, fever, and weight loss can be symptoms. Crohn’s disease can be associated with reddish tender skin nodules, and inflammation of the joints, spine, eyes, and liver. Diagnosis is by barium enema, barium x-ray of the small bowel, and colonoscopy. Treatment includes medications for inflammation, immune suppression, antibiotics, or surgery.

Enteritis, granulomatous: Crohn’s disease by another name, a chronic inflammatory disease of the intestine primarily in the small and large intestines but which can occur anywhere in the digestive system between the mouth and the anus. Named after Burrill Crohn who described the disease in 1932. The disease usually affects persons in their teens or early twenties. It tends to be a chronic, recurrent condition with periods of remission and exacerbation. In the early stages, Crohn’s disease causes small scattered shallow crater-like areas (erosions) called apthous ulcers in the inner surface of the bowel. With time, deeper and larger ulcers develop, causinG scarring and stiffness of the bowel and the bowel becomes increasingly narrowed, leading to obstruction. Deep ulcers can puncture holes in the bowel wall, leading to infection in the abdominal cavity (peritonitis) and in adjacent organs.When only the large intestine (colon) is involved, the condition is called Crohn’s colitis. When only the small intestine is involved, the condition is called Crohn’s enteritis. When only the end of the small intestine (the terminal ileum) is involved, it is termed terminal ileitis. When both the small intestine and the large intestine are involved, the condition is called Crohn’s enterocolitis (or ileocolitis). Abdominal pain, diarrhea, vomiting, fever, and weight loss can be symptoms. Crohn’s disease can be associated with reddish tender skin nodules, and inflammation of the joints, spine, eyes, and liver. Diagnosis is by barium enema, barium x-ray of the small bowel, and colonoscopy. Treatment includes medications for inflammation, immune suppression, antibiotics, or surgery. (The disease is also called regional enteritis).

Enteritis, regional: Crohn’s disease by another name, a chronic inflammatory disease of the intestine primarily in the small and large intestines but which can occur anywhere in the digestive system between the mouth and the anus. Named after Burrill Crohn who described the disease in 1932. The disease usually affects persons in their teens or early twenties. It tends to be a chronic, recurrent condition with periods of remission and exacerbation. In the early stages, Crohn’s disease causes small scattered shallow crater-like areas (erosions) called apthous ulcers in the inner surface of the bowel. With time, deeper and larger ulcers develop, causing scarring and stiffness of the bowel and the bowel becomes increasingly narrowed, leading to obstruction. Deep ulcers can puncture holes in the bowel wall, leading to infection in the abdominal cavity (peritonitis) and in adjacent organs. When only the large intestine (colon) is involved, the condition is called Crohn’s colitis. When only the small intestine is involved, the condition is called Crohn’s enteritis. When only the end of the small intestine (the terminal ileum) is involved, it is termed terminal ileitis. When both the small intestine and the large intestine are involved, the condition is called Crohn’s enterocolitis (or ileocolitis). Abdominal pain, diarrhea, vomiting, fever, and weight loss can be symptoms. Crohn’s disease can be associated with reddish tender skin nodules, and inflammation of the joints, spine, eyes, and liver. Diagnosis is by barium enema, barium x-ray of the small bowel, and colonoscopy. Treatment includes medications for inflammation, immune suppression, antibiotics, or surgery. (The disease is also called granulomatous enteritis).

Entero-: Combining form that means the intestine (gut). Comes from the Greek word enteron for intestine, related to the Greek enteros meaning within. What went within the intestine was within the body.

Enterocolitis, Crohn’s: Crohn’s disease involving both the small and large intestines. Crohn’s is a chronic inflammatory disease of the intestine primarily affecting the small and large intestines but which can occur anywhere in the digestive system between the mouth and the anus. Named after Burrill Crohn who described the disease in 1932. The disease usually affects persons in their teens or early twenties. It tends to be a chronic, recurrent condition with periods of remission and exacerbation. In the early stages, Crohn’s disease causes small scattered shallow crater-like areas (erosions) called apthous ulcers in the inner surface of the bowel. With time, deeper and larger ulcers develop, causing scarring and stiffness of the bowel and the bowel becomes increasingly narrowed, leading to obstruction. Deep ulcers can puncture holes in the bowel wall, leading to infection in the abdominal cavity (peritonitis) and in adjacent organs. Abdominal pain, diarrhea, vomiting, fever, and weight loss can be symptoms. Crohn’s disease can be associated with reddish tender skin nodules, and inflammation of the joints, spine, eyes, and liver. Diagnosis is by barium enema, barium x-ray of the small bowel, and colonoscopy. Treatment includes medications for inflammation, immune suppression, antibiotics, or surgery. (The disease is also called regional enteritis and granulomatous enteritis).

Enteropathy: Any pathology (disease) of the intestine.

Enteropathy, gluten: A condition in which the absorption of food nutrients through the small intestine is impaired because of an immune (allergic) reaction to gluten, a protein found in wheat or related grains and many other foods. Frequent diarrhea and weight loss can be symptoms. A skin condition called dermatitis herpetiformis can be associated with gluten enteropathy. The most accurate test is a biopsy of the involved small bowel. Treatment is avoidance of gluten in the diet. Medications are used, if need be.

Enteropathy, protein-losing: Condition in which plasma protein is lost to excess into the intestine. This can be due to diverse causes including gluten enteropathy, extensive ulceration of the intestine, intestinal lymphatic blockage, and infiltration of leukemic cells into the intestinal wall.

Enterostomal therapist: A health care specialist trained to help patients care for and adjust to their colostomy.

Enuresis: Bedwetting.

Environmental tobacco smoke: Smoke that comes from the burning end of a cigarette and smoke that is exhaled by smokers. Also called ETS or second-hand smoke. Inhaling ETS is called involuntary or passive smoking.

Enzyme: A protein that acts as a catalyst to mediate and speed a specific chemical reaction.

Enzyme defect: A disorder resulting from a deficiency (or functional abnormality) of an enzyme. In 1902 Archibald Garrod first attributed a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as PKU (phenylketonuria) and galactosemia, an error in the handling (metabolism) of the sugar galactose.

Eosinophil: A type of white blood cell. For example, the numbers of eosinophils in blood often rise in allergy.

Eosinophilic fasciitis (Shulman’s syndrome): A disease which leads to inflammation and thickening of the skin and fascia. (The fascia is a lining tissue under the skin that covers a surface of underlying tissues. When the fascia is inflamed, the condition is referred to as "fasciitis.") In eosinophilic fasciitis, the involved fascia is inflamed with the eosinophil white blood cells. There is progressive thickening, and often redness and warmth, and hardness of the skin surface.

Ependymoma: A type of brain tumor.

Epicanthal fold: A fold of skin that comes down across the inner angle of the eye. The epicanthal fold is more common in children with Down syndrome and other birth defects than normal children and so is of value in diagnosis. Although some dictionaries state that this eye fold is found in peoples of Asian origin, this is not true. The normal Asian eyefold is continuous with the lower edge of the upper eyelid and actually appears distinctly different than a true epicanthal fold.

Epicardium: The thin surface layer of the heart. Also considered part of the pericardium, it consists of a layer of mesothelial cells and underlying stromal layer.

Epidemic: A sudden outbreak as, for example, of cholera. The opposite of endemic (continuously present). The word epidemic came from the Greek "epidemios" meaning "among the people."

Epidemic typhus: A severe acute disease with prolonged high fever up to 40° C (104° F), intractable headache, and a pink-to-red raised rash. The cause is a microorganism called Rickettsia prowazekii. It is found worldwide and is transmitted by lice. The lice become infected on typhus patients and transmit illness to other people. The mortality increases with age and over half of untreated persons age 50 or more die. Also called European, classic, or louse-borne typhus and jail fever.

Epidemiologist: A person engaged in epidemiology (not confined to epidemics). Epidemiologists include people with an M.D., Ph.D., D.P.H. (Doctor of Public Health), M.P.H. (Master of Public Health), R.N., and a number of other degrees.

Epidemiology, classical: The study of populations in order to determine the frequency and distribution of disease and measure risks.

Epidemiology, clinical: Epidemiology focused specifically upon patients.

Epidermis: The upper or outer layer of the two main layers of cells that make up the skin.

Epidermoid carcinoma: A type of lung cancer in which the cells are flat and look like fish scales. Also called squamous cell carcinoma.

Epididymis: A structure within the scrotum attached to the backside of the testis. The epididymis is a coiled segment of the spermatic ducts that serves to store, mature and transport spermatozoa between the testis and the vas (the vas deferens).

Epididymitis: Inflammation of the epididymis.

Epigastrium: The part of the abdominal wall above the umbilicus (belly button). The hypogastrium is the part of the abdominal wall below the umbilicus. The abdominal wall can thus be divided into upper and lower halves. Or it can be further divided into quadrants by also drawing a vertical line through the umbilicus.

Epiglottis: The flap that covers the trachea during swallowing so that food does not enter the lungs. Not everything in medicine is perfectly logical. The name epiglottis was compounded from "epi-" and "-glottis" from the Greek "glotta" meaning "tongue" since it was once believed that the epiglottis was attached to the tongue!

Epilepsy (seizure disorder): When nerve cells in the brain fire electrical impulses at a rate of up to four times higher than normal, this causes a sort of electrical storm in the brain, known as a seizure. A pattern of repeated seizures is referred to as epilepsy. Known causes include head injuries, brain tumors, lead poisoning, maldevelopment of the brain, genetic and infectious illnesses. But in fully half of cases, no cause can be found. Medication controls seizures for the majority of patients.

Epinephrine: A substance produced by the medulla (inside) of the adrenal gland. The name epinephrine was coined in 1898 by the American pharmacologist and physiologic chemist (biochemist) John Jacob Abel who isolated it from the adrenal gland which is located above (epi-) the kidney ("nephros" in Greek). (Abel also crystallized insulin). Technically speaking, epinephrine is a sympathomimetic catcholamine. It causes quickening of the heart beat, strengthens the force of the heart’s contraction, opens up the airways (bronchioles) in the lungs and has numerous other effects. The secretion of epinephrine by the adrenal is part of the fight-or-flight reaction. Adrenaline is a synonym of epinephrine and is the official name in the British Pharmacopoeia.

Epiphysis: The growth area of a bone near the end.

Episiotomy: Surgical procedure for widening the outlet of the birth canal to facilitate delivery of the baby and avoid a jagged rip of the perineum (the area between the anus and the vulva, the labial opening to the vagina).

Epispadias: Congenital (at birth) malformation in which the opening of the urethra (from whence comes the urinary stream) is on the dorsum (topside) of the penis. Hypospadias is the corresponding malformation in which the opening of the urethra is on the ventral surface (underside) of the penis.

Epistaxis: Medical term for nosebleed. The nose is a part of the body that is very rich in blood vessels (vascular) and is situated in a vulnerable position on the face. As a result, any trauma to the face can cause bleeding which may be profuse. Nosebleeds can occur spontaneously when the nasal membranes dry out, crust, and crack, as is common in dry climates, or during the winter months when the air is dry and warm from household heaters. People are more susceptible if they are taking medications which prevent normal blood clotting (coumadin, warfarin, aspirin, or any anti-inflammatory medication). Other predisposing factors include infection, trauma, allergic and non-allergic rhinitis, hypertension, alcohol abuse, and inherited bleeding problems.

Epistaxis, treatment of: To stop epistaxis (a nosebleed), you should: 1. Pinch all the soft parts of the nose together between your thumb and index finger. 2. Press firmly toward the face - compressing the pinched parts of the nose against the bones of the face. 3. Hold the nose for at least 5 minutes (timed by the clock). Repeat as necessary until the nose has stopped bleeding. 4. Sit quietly, keeping the head higher than the level of the heart; that is, sit up or lie with the head elevated. Do not lay flat or put your head between your legs. 5. Apply ice (crushed in a plastic bag or washcloth) to nose and cheeks.

Epithelial carcinoma: Cancer that begins in the cells that line an organ.

Epithelium: The outside layer of cells that covers all the free, open surfaces of the body including the skin, and mucous membranes that communicate with the outside of the body. By contrast the endothelium is the layer of cells lining the closed internal spaces of the body such as the blood vessels and lymphatic vessels (that convey the lymph, a milky fluid).

Eponym: Something named after someone. For example, a condition called Shiel’s syndrome might be named after someone named Shiel who discovered it or described and clearly delineated it.

Epstein-Barr Virus: A virus that can cause infectious mononucleosis ("mono").

ERCP (endoscopic retrograde cholangiopancreatogram): A diagnostic procedure to examine diseases of the liver, bile ducts and pancreas. It is uncomfortable but not painful, is performed under intravenous sedation, usually without general anesthesia, and has a low incidence of complications. ERCP provides important information unobtainable by other diagnostic means. Therapeutic measures can often be take at the time of ERCP to remove stones in the bile ducts or to relieve obstructions of the bile ducts.

ERCP (Endoscopic Retrograde Cholangio-Pancreatography): A diagnostic procedure to examine diseases of the liver, bile ducts and pancreas. It is uncomfortable but not painful, is performed under intravenous sedation, usually without general anesthesia, and has a low incidence of complications. ERCP provides important information unobtainable by other diagnostic means. Therapeutic measures can often be take at the time of ERCP to remove stones in the bile ducts or to relieve obstructions of the bile ducts.

Erectile dysfunction: A consistent inability to sustain an erection sufficient for sexual intercourse. Also commonaly known as "impotence." Medically, the term "erectile dysfunction" is used to differentiate impotence from other problems that interfere with sexual intercourse (such as lack of sexual desire and problems with ejaculation and orgasm). Impotence usually has a physical cause, such as disease, injury, drug side-effects, or a disorder that impairs blood flow in the penis. Impotence is treatable in all age groups.

Erection, penile: When the penis fills with blood and is rigid. The penis contains two chambers, called the corpora cavernosa, which run the length of the organ, are filled with spongy tissue, and surrounded by a membrane, called the tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues, spaces, veins, and arteries. The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa. Erection begins with sensory and mental stimulation. Impulses from the brain and local nerves cause the muscles of the corpora cavernosa to relax, allowing blood to flow in and fill the open spaces. The blood creates pressure in the corpora cavernosa, making the penis expand. The tunica albuginea helps to trap the blood in the corpora cavernosa, thereby sustaining erection. Erection is reversed when muscles in the penis contract, stopping the inflow of blood and opening outflow channels.

Erythema: A redness of the skin resulting from inflammation, for example, as caused by sunburn.

Erythema chronicum migrans: The classic initial rash of Lyme disease. In the early phase of the illness, within hours to weeks of the tick bite, the local skin develops an expanding ring of unraised redness. There may be an outer ring of brighter redness and a central area of clearing. For more information, see LYME DISEASE.

Erythema infectiosum: A Latin name for fifth disease—because in the pre-vaccination era, it was frequently the "fifth disease" that a child would develop—caused by a virus known as parvovirus B 19. Symptoms include low-grade fever, fatigue, a "slapped cheeks rash," and a rash over the whole body. While the illness is not serious in children, 80% of adults have joint aches and pains (arthritis) which may become long-term with stiffness in the morning, redness and swelling of the same joints on both sides of the body (a "symmetrical" arthritis), most commonly involving the knees, fingers, and wrists. Pregnant women (who have not previously had the illness) should avoid contact with patients who have fifth disease. The fifth disease virus can infect the fetus prior to birth. And, while no birth defects have been reported as a result of fifth disease, it can cause the death of the unborn fetus. The risk of fetal death is 5-10% if the mother becomes infected.

Erythrocytes: Cells that carry oxygen to all parts of the body. Also called red blood cells (RBCs).

Erythrocyte membrane protein band 4.1 (EPB41): See Elliptocytosis.

Erythroleukemia: Leukemia that develops in erythrocytes. In this rare disease, the body produces large numbers of abnormal red blood cells.

Erythroplakia: A reddened patch with a velvety surface found in the mouth.

Eschar: The scab formed when a wound or skin is sealed by the heat of cautery or burning. Also the dark crusted ulcer (tache noire) at the site of the chigger (mite larva) bite in scrub typhus.

Esophageal: Related to the esophagus.

Esophageal cancer: Cancer of the esophagus (the swallowing tube that passes from the throat to the stomach). The risk of cancer of the esophagus is increased by long-term irritation of the esophagus such as with smoking, heavy alcohol intake, and Barrett’s esophagitis. Cancer of the esophagus can cause difficulty and pain with swallowing solid food. Diagnosis of esophageal cancer can be made by barium x-ray of the esophagus, and confirmed by endoscopy with biopsy of the cancer tissue.

Esophageal reflux: A condition wherein stomach contents regurgitate or back up (reflux) into the esophagus (a long cylindrical tube that transports food from the mouth to the stomach). The food in the stomach is partially digested by stomach acid and enzymes. Normally, the partially digested acid content in the stomach is delivered by the stomach muscle into the small intestine for further digestion. In esophageal reflux, stomach acid content refluxes backwards up into the esophagus, occasionally reaching the breathing passages, causing inflammation and damage to the esophagus, as well as to the lung and larynx (the voice box). The process is medically termed gastroesophageal reflux disease (GERD). 10% of patients with GERD develop a Barrett’s esophagus which can increase the risk of cancer of the esophagus.

Esophageal speech: Speech produced with air trapped in the esophagus and forced out again.

Esophageal stricture, acute: A narrowing or closure of the normal opening of the swallowing tube leading to the stomach, usually caused by scarring from acid irritation. Acute, complete obstruction of the esophagus occurs when food (usually meat) is lodged in the esophageal stricture. Patients experience chest pain, and are unable to swallow saliva. Attempts to relieve the obstruction by inducing vomiting at home are usually unsuccessful. Patients with complete esophageal obstruction can breathe, and are not at any risk of suffocation. Endoscopy is usually employed to retrieve the meat and relieve the obstruction.

Esophageal stricture, chronic: A longstanding narrowing or closure of the normal opening of the swallowing tube leading to the stomach, usually caused by scarring by acid irritation. Narrowing of the esophagus. A common complication of chronic gastroesophageal reflux disease (GERD). Severa procedures are available for stretching (dilating) the strictures without having to resort to surgery. One of the procedures involves placing a deflated balloon across the stricture at the time of endoscopy. The balloon is then inflated, thereby opening the narrowingcaused by the stricture. Another method involves inserting tapered dilators of different sizes through the mouth into the esophagus to dilate the stricture.

Esophageal ulcer: A hole in the lining of the esophagus corroded by the acidic digestive juices secreted by the stomach cells. Ulcer formation is related to H. pyloridus bacteria in the stomach, anti-inflammatory medications, and smoking cigarettes. Ulcer pain may not correlate with the presence or severity of ulceration. Diagnosis is made with barium x-ray or endoscopy. Complications of ulcers include bleeding and perforation. Treatment involves antibiotics to eradicate H. pyloridus, eliminating risk factors, and preventing complications.

Esophagectomy: An operation to remove a portion of the esophagus.

Esophagitis: Inflammation of the esophagus. The esophagus is that soft tube-like portion of the digestive tract connecting the pharynx with the stomach.

Esophagogastroduodenoscopy: Also known as EGD (for EsophagoGastroDuodenoscopy) or as upper endoscopy. A procedure that enables the examiner ( usually a gastroenterologist) to examine the esophagus (swallowing tube ), stomach, and duodenum (first portion of small bowel ) using a thin flexible tube (a "scope") that can be looked through or seen on a TV monitor. (A great crossword puzzle/trivia term!)

Esophagoscopy: Examination of the esophagus using a thin, lighted instrument.

Esophagram: A series of x-rays of the esophagus. The x-ray pictures are taken after the patient drinks a solution that coats and outlines the walls of the esophagus. Also called a barium swallow.

Esophagus: The esophagus is that soft tube-like portion of the digestive tract connecting the pharynx with the stomach. It has a muscular wall composed of "smooth muscle." It is commonly referred to as the "gullet."

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

EST: Expressed sequence tag. A sequence tagged site (STS) derived from cDNA (complementary DNA). An STS is a short (200 to 500 base pairs) DNA sequence that has a single occurrence in the human genome and whose location and base sequence are known. Detectable by polymerase chain reaction, STSs are useful for localizing and orienting the mapping and sequence data reported from many different laboratories and serve as landmarks on the developing physical map of the human genome.

Estrogen: Estrogen is a female hormone produced by the ovaries. Estrogen deficiency can lead to osteoporosis.

Estrogen, designer: An engineered drug that possesses some, but not all, of the actions of estrogen. Designer estrogens are selective estrogen-receptor modulators (SERMs). For example, raloxifene (trade name Evista) is classified as a SERM because it prevents bone loss (like estrogen) and lowers serum cholesterol (like estrogen) but (unlike estrogen) does not stimulate the endometrial lining of the uterus.

Esotropia: Cross-eyed or, in medical terms, convergent or internal strabismus.

Essential: As in essential hypertension. A hallowed term meaning "We don't know the cause." Synonymous with idiopathic.

Eugenics: Literally, meaning normal genes, eugenics aims to improve the genetic constitution of the human species by selective breed