Dictionary

enzyme-linked immunosorbent assay See ELISA.

eosinophil A normal type of white blood cell that has coarse granules within its cytoplasm. Eosinophils are produced in the bone marrow and migrate to tissues throughout the body. When a foreign substance enters the body, other types of white blood cells (lymphcytes and neutrophils) release substances to attract eosinophils and then release toxic substances…

eosinophilia An abnormally high number of eosinophils in the blood. Normally, eosinophils constitute 1 percent to 3 percent of the peripheral blood leukocytes, at a count of 350 to 650 per cubic millimeter. In areas of the world where parasite diseases are common, they are the usual cause of eosinophilia. In developed nations, eosinophilia is…

eosinophilic fasciitis A disease that leads to inflammation and thickening of the skin and of the lining tissue under the skin that covers the surface of underlying tissues (fascia). In eosinophilic fasciitis, the involved fascia is inflamed with the eosinophil white blood cells. Progressive thickening occurs, and often redness, warmth, and hardness of the skin…

eosinophilic granuloma A disease in which histiocytes multiply and attack the tissues, forming solitary or multiple eosinophilic granulomas. Eosinophilic granuloma predominantly affects children and young adults. It is the most common type of Langerhans cell histiocytosis. In patients with eosinophilic granuloma, granulomas may develop in bone, with overlying tender and sometimes warm areas of swelling…

ependymoma A type of brain tumor that derives from the glial cells that line the cavities within the brain’s ventricles. Because cerebrospinal fluid normally flows through these ventricles, blockage due to an ependymoma can cause buildup of fluid, pressure on the brain, and hydrocephalus.

ephedrine A vasoconstricting, bronchodilating drug that is used to treat asthma and also found in over-the-counter remedies for cold and flu symptoms and in some herbal remedies (in the form of the ephedrine-containing herbs ephedra or Ma Huang). Side effects of ephedrine can include jitteriness, racing heartbeat, nausea, sleeplessness, and headache. Ephedrine misuse or abuse…

epicanthal fold A fold of skin that comes down across the inner angle of the eye. Epicanthal folds appear most frequently in persons with Down syndrome and some other constellations of birth defects. To the untrained eye, an epicanthal fold may look similar to the eye fold found in peoples of Asian origin, but the…

epicardium See pericardium, visceral.

epidemic The occurrence of more cases of a disease than would be expected to occur in a community or region during a given time period. A sudden outbreak (as, for example, of cholera). See also endemic; pandemic.

epidemic hemorrhagic fever See hemorrhagic fever, viral.

epidemic myalgia See Bornholm disease.