polycythemia
Polycythemia (also known as polycythaemia, polyglobulia and Erythrocytosis) is a disease state in which the hematocrit (the volume percentage of red blood cells in the blood) and/or hemoglobin concentration are elevated in peripheral blood. It can be due to an increase in the number of red blood cells ("absolute polycythemia") or to a decrease in the volume of plasma ("relative polycythemia"). Polycythemia is sometimes called erythrocytosis, but the terms are not synonymous, because polycythemia describes any increase in red blood mass (whether due to an erythrocytosis or not), whereas erythrocytosis is a documented increase of red cell count. The emergency treatment of polycythemia (e.g., in hyperviscosity or thrombosis) is by phlebotomy (removal of blood from the circulation). Depending on the underlying cause, phlebotomy may also be used on a regular basis to reduce the hematocrit. Myelosuppressive medications such as hydroxyurea are sometimes used for long-term management of polycythemia.
Human disease
disease (individual) disease (class) clinical sign hematologic disorder