The proposed revised World Health Organization criteria for the diagnosis of polycythemia vera (p. vera) requires two major criteria and one minor criterion or the first major criterion together with two minor criteria.
Leukemia is an abnormal rise in the number of white blood cells. The white blood cells crowd out other blood cell elements such as red blood cells and platelets. The elevated white blood cells are immature and do not function properly.
Leukemia -- the term derives from the Greek words for "white" and "blood" -- is often considered a disease of children, yet it actually affects far more adults. It is more common in men than women and in Caucasians than African-Americans. There will be more than...
Hemoglobin of more than 18.5 g/dL in men, 16.5 g/dL in women, or elevated red cell mass greater than 25% above mean normal predicted value.
Presence of JAK2 617V greater than F or other functionally similar mutations, such as the exon 12 mutation of JAK2.
Bone marrow biopsy showing hypercellularity with prominent erythroid, granulocytic, and megakaryocytic proliferation.
Serum erythropoietin level below normal range.
Endogenous erythroid colony formation in vitro.
Other confirmatory findings no longer required for diagnosis include:[2,3,4]
Oxygen saturation with arterial blood gas greater than 92%.
Thrombocytosis (>400,000 platelets/mm3).
Leukocyte alkaline phosphatase (>100 units in the absence of fever or infection).
There is no staging system for this disease.
Patients have an increased risk of cardiovascular and thrombotic events and transformation to acute myelogenous leukemia or primary myelofibrosis.[5,6,7] Age older than 65 years, leukocytosis, and a history of vascular events (bleeding or thrombosis) are associated with a poor prognosis.[5,8,9]
The primary therapy for p. vera includes intermittent, chronic phlebotomy to maintain the hematocrit below 45%, and this recommendation has been confirmed in a randomized, prospective trial, which demonstrated lower rates of cardiovascular death and major thrombosis using this hematocrit target.[10,11] The target level for women may need to be lower (e.g., hematocrit <40%), but there are no empiric data to confirm this recommendation.
Complications of phlebotomy include:
Progressive and sometimes extreme thrombocytosis and symptomatology related to chronic iron deficiency, including pica, angular stomatitis, and glossitis.
Dysphagia that is the result of esophageal webs (very rare).
Possibly muscle weakness.
(Refer to the PDQ summary on Oral Complications of Chemotherapy and Head/Neck Radiation for more information.)
In addition, progressive splenomegaly or pruritus not controllable by antihistamines may persist despite control of the hematocrit by phlebotomy. (Refer to the PDQ summary on Pruritus for more information.) If phlebotomy becomes impractical, hydroxyurea or interferon-alpha can be added to control the disease.