Elevated RI, polychromasia and nucleated RBCs on smear; also spherocytes, elliptocytes, schistocytes, or target, spur, or sickle cells may be present depending on disorder; elevated unconjugated serum bilirubin and LDH, elevated plasma hemoglobin, low or absent haptoglobin; urine hemosiderin present in intravascular but not extravascular hemolysis, Coombs' test (immunohemolytic anemias), osmotic fragility test (hereditary spherocytosis), hemoglobin electrophoresis (sickle cell anemia, thalassemia), G6PD assay (best performed after resolution of hemolytic episode to prevent false-negative result).
Treatment: Anemia General Approaches  The acuteness and severity of the anemia determine whether transfusion therapy with packed RBCs is indicated. Rapid occurrence of severe anemia (e.g., after acute GI hemorrhage resulting in Hct<25%, following volume repletion) or development of angina or other symptoms is an indication for transfusion. Hct should increase 3-4% [Hb by 10 g/L (1 g/dL)] with each unit of packed RBCs, assuming no ongoing losses. Chronic anemia (e.g., vitamin B12 deficiency), even when severe, may not require transfusion therapy if the pt is compensated and specific therapy (e.g., vitamin B12) is instituted. Specific Disorders - Iron deficiency: find and treat cause of blood loss, oral iron (e.g., FeSO4 300 mg tid).
- Folate deficiency: common in malnourished, alcoholics; less common now than before folate food supplementation; folic acid 1 mg PO qd (5 mg qd for pts with malabsorption).
- Vitamin B12deficiency: can be managed either with parenteral vitamin B12 100 µg IM qd for 7 d, then 100-1000 µg IM per month or with 2 mg oral crystalline vitamin B12 per day. An inhaled formulation is also available.
- Anemia of chronic disease: treat underlying disease; in uremia use recombinant human erythropoietin, 50-150 U/kg three times a week; role of erythropoietin in other forms of anemia of chronic disease is less clear; response more likely if serum erythropoietin levels are low. Target Hb 9-10 g/dL. Iron administration is not useful.
- Sickle cell anemia: hydroxyurea 10-30 mg/kg per day PO increases level of Hemoglobin F (HbF) and prevents sickling, treat infections early, supplemental folic acid; painful crises treated with oxygen, analgesics (opioids), hydration, and hypertransfusion; consider allogeneic bone marrow transplantation in pts with increasing frequency of crises.
- Thalassemia: transfusion to maintain Hb >90 g/L (>9 g/dL), folic acid, prevention of Fe overload with deferoxamine (parenteral) or deferasirox (oral) chelation; consider splenectomy and allogeneic bone marrow transplantation.
- Aplastic anemia: antithymocyte globulin and cyclosporine leads to improvement in 70%, bone marrow transplantation in young pts with a matched donor.
- Autoimmune hemolysis: glucocorticoids, sometimes immunosuppressive agents, danazol, plasmapheresis, rituximab.
- G6PD deficiency: avoid agents known to precipitate hemolysis.
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For a more detailed discussion, see Adamson JW: Iron Deficiency and Other Hypoproliferative Anemias, Chap. 126, p. 625; Benz EJ: Disorders of Hemoglobin, Chap. 127, p. 631; Hoffbrand AV: Megaloblastic Anemias, Chap. 128, p. 640; Luzzato L: Hemolytic Anemias and Anemia Due to Acute Blood Loss, Chap. 129, p. 649; and Young NS: Bone Marrow Failure Syndromes Including Aplastic Anemia and Myelodysplasia, Chap. 130; p. 662 in HPIM-19. |
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