'Common' uncommon anemias

Of the uncommon anemias, "common" types include the anemia of renal disease, thalassemia, myelodysplastic syndrome and the anemia of chronic disease. These conditions may be suggested by the clinical presentation, laboratory test values and peripheral blood smear, or by failure of the anemia to respond to iron supplements or nutrient replacement. The principal cause of the anemia of renal disease is a decreased production of red blood cells related to a relative deficiency of erythropoietin. When treatment is required, erythropoietin is administered, often with iron supplementation. In the anemia of chronic disease, impaired iron transport decreases red blood cell production. Treatment is predominantly directed at the underlying condition. Since iron stores are usually normal, iron administration is not beneficial. Thalassemia minor results from a congenital abnormality of hemoglobin synthesis. The disorder may masquerade as mild iron deficiency anemia, but iron therapy and transfusions are often not indicated. In the myelodysplastic syndrome, blood cell components fail to mature, and the condition may progress to acute nonlymphocytic leukemia. The rate of progression depends on the subtype of myelodysplasia, but the leukemia is usually resistant to therapy.