Virginia C. Broudy, MD

University of Washington School of Medicine, Seattle, WA

This case was reviewed and updated in August 2013 by Dr. Eric Kraut and members of the Teaching Cases Subcommittee.

Copyright of the American Society of Hematology, 2006. ISSN: 1931-6860.


The three pathophysiologic categories of polycythemia are:
  • Relative polycythemia (red blood cell mass normal; plasma volume decreased)
  • Secondary polycythemia (red blood cell mass increased)
  • Polycythemia vera (red blood cell mass increased)

Comparison of Polycythemia Vera and Secondary Polycythemia
  Polycythemia Vera Secondary Polycythemia
Pathophysiology Neoplastic hematopoietic stem cell disorder Due to tissue hypoxia causing an appropriate increase in Epo production, or to renal or hepatic disease causing an inappropriate increase in Epo production
CBC Hct and often WBC and platelets are increased Only Hct is increased
Epo level Decreased or low normal Normal or increased
Treatment Phlebotomy and/or hydroxyurea to keep Hct below 45%; most patients should also take aspirin 81 mg daily to decrease the risk of thrombosis Treatment is usually not required

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