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There are two distinct forms of the disease: Primary polycythemia (polycythemia vera) is a myeloproliferative disorder of unknown etiology. It is characterized by hyperplasia of the cell-forming tissues of the bone marrow, with resultant elevation of the erythrocyte count and hemoglobin level, and an increase in the number of leukocytes and platelets.
Secondary polycythemia is a physiologic condition resulting from a deficient oxygen supply to the tissues. The body attempts to compensate for the deficiency by manufacturing more hemoglobin and erythrocytes. Living at high altitudes can produce polycythemia, as can severe chronic lung and heart disorders, especially congenital heart defects.
Absolute polycythemia refers to an increase in red cell mass from any cause. Relative polycythemia refers to a loss of plasma volume causing an elevated hematocrit.
See also: polycythemia.
polycythemiaAny ↑ RBC mass. See Relative polycythemia, Secondary polycythemia.
polycythemia(pol?e-si-the'me-a) [ poly- + cyto- + -emia]
spurious polycythemiaGaisböck syndrome.
Usually occurring between ages 40 and 60 and most common in males with Jewish ancestry, polycythemia seldom affects children or those of African ancestry. Weakness, fatigue, headache, blood clotting, vertigo, tinnitus, irritability, dyspnea, visual disturbances, flushing of face, redness, or ruddy cyanosis, pruritus, ecchymosis, hypertension, epigastric distress, weight loss, and pain in joints or extremities occur commonly. The bone marrow shows uncontrolled, rapid cellular reproduction and maturation (increased cellularity). Peptic ulcers are often reported.
The mainstay of patient care is the reduction in red blood cell mass with recurrent phlebotomy to lower the hematocrit to 45% or less. Vitals signs are monitored during and after phlebotomy, and the patient is provided with oral fluids and protected from orthostatic hypotension. The symptoms and the need to seek medical attention when signs and symptoms of bleeding and thrombus formation occur are explained to the patient. Rest should be balanced with exercise, but the patient should be advised that activity and ambulation help prevent thrombotic complications. Reassurance and support are provided to the patient and family, and opportunities are provided for questions and discussion of concerns. Patients who have a history of blood clotting or very high platelet counts are treated with myelosuppressive drugs, such as hydroxyurea. During myelosuppressive therapy the patient is informed about adverse effects that may occur, assessed for leukopenia and thrombocytopenia, and protective measures are taught and instituted.