polycythemia

World English Dictionary
polycythaemia or esp (US) polycythemia (ˌpɒlɪsaɪˈθiːmɪə)
 
n
an abnormal condition of the blood characterized by an increase in the number of red blood cells. It can occur as a primary disease of unknown cause (polycythaemia vera or erythraemia) or in association with respiratory or circulatory diseases
 
[C19: from poly- + cyto- + -haemia]
 
polycythemia or esp (US) polycythemia
 
n
 
[C19: from poly- + cyto- + -haemia]

Collins English Dictionary - Complete & Unabridged 10th Edition
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American Heritage
Medical Dictionary

polycythemia pol·y·cy·the·mi·a (pŏl'ē-sī-thē'mē-ə)
n.
A condition characterized by an abnormal increase in the number of red blood cells in the blood. Also called erythrocythemia, hypercythemia, hypererythrocythemia, hyperglobulia.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Britannica
Encyclopedia

polycythemia

abnormal increase in red blood cells and hemoglobin in the circulation, a situation that results in thickened blood, retarded flow, and an increased danger of clot formation within the circulatory system. Polycythemia may be relative (e.g., after blood-plasma loss), transient (as when a large number of red blood cells suddenly enter the circulation from storage), or absolute (i.e., reflecting an increase in actual mass of red cells in the body). Relative and transient, or secondary, polycythemia disappear when the condition to which they are secondary is eliminated. Absolute polycythemia, when the cause is known, is called erythrocytosis; this may accompany congenital heart disease, some hemoglobin defects, pulmonary disease (e.g., emphysema, silicosis), the Pickwickian syndrome (a form of obesity), and living at high altitudes.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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