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In some patients, the bone marrow eventually becomes fibrotic, hematopoiesis developsin the spleen, and anemia follows. In a few patients, acute myeloblastic leukemiadevelops in the later stages, especially if treatment has involved chemotherapy.
9/26/18, 5*38 PMPage 61 of 74EtiologyPrimary polycythemia is a neoplastic disorder of unknown origin that commonlydevelops between the ages of 40 and 60 years, although younger individuals can beaffected. Secondary polycythemia may be a compensation mechanism intended toprovide increased oxygen transport in the presence of chronic lung disease or heartdisease or from living at high altitudes. Some cases result from erythropoietin-secretingtumors such as renal carcinoma.Signs and SymptomsThe patient appears plethoricplethoric and cyanoticcyanotic, with the deep bluish-red tone of the skinand mucosa resulting from the engorged blood vessels and sluggish blood flow.HepatomegalyHepatomegaly, an enlarged liver, and splenomegaly are present. Pruritus is common.Blood pressure increases, the pulse is full and bounding, and dyspnea, headaches, orvisual disturbances are common. Thromboses and infarctions may affect the extremities,liver, or kidneys as well as the brain or the heart. Congestive heart failure frequentlydevelops because of the increased work load resulting from the increased volume andviscosity of blood. High levels of uric acid resulting from cell destruction result in severejoint pain.Diagnostic TestsCell counts are increased, as are hemoglobin values, and hematocrit is elevated. Inpolycythemia vera, the malignant or abnormal cell is the erythrocyte. Bone marrow ishypercellular, with the red marrow replacing some fatty marrow. Hyperuricemia ispresent because of the high cell destruction rate.
9/26/18, 5*38 PMPage 62 of 74PRINTED BY: [email protected] Printing is for personal, private use only. No part of this book may be reproduced or transmitted without publisher's prior permission. Violators will be prosecuted.TreatmentDrugs or radiation may be used to suppress the activity of the bone marrow. There issignificant risk that fibrosis or leukemia may develop with these methods. Periodicphlebotomyphlebotomy, or removal of blood, may be used to minimize the possibility ofthromboses or hemorrhages.10-8Think aboutCompare the general effects of anemia and polycythemia in terms of hemoglobin level,hematocrit, general appearance, and possible complications.The LeukemiasThe leukemias are a group of neoplastic disorders involving the white blood cells. Theestimated number of new cases of leukemia each year is 31,000 including 2500 children.