INDEPENDENCE DAY. On July 4, 1776, the thirteen colonies claimed their independence from England, an event which eventually led to the formation of the United States.
Polycythemia vera is a rare, chronic disorder involving the overproduction of blood cells in the bone marrow (myeloproliferation). The overproduction of red blood cells is most dramatic, but the production of white blood cells and platelets are also elevated in most cases.
There are two primary types of polycythemia: polycythemia vera and secondary polycythemia. The causes, symptoms, and treatments of the two conditions vary. Polycythemia vera is more serious and can lead to more critical complications than secondary polycythemia.