Color Atlas of Hematology - Practical Microscopic and Clinical ...

134 Erythrocyte and Thrombocyte AbnormalitiesHypochromic Infectious or Toxic Anemia(Secondary Anemia)Among the various causes of lack of iron for erythropoiesis (see Fig. 44,p. 129), a special situation is represented by the internal iron shift causedby “iron pull” of the reticuloendothelial system (RES) during infections,toxic processes, autoimmune diseases, and tumors. Since this anemia resultsfrom another disorder, it is also called secondary anemia. The MCH ishypochromic, or in rare instances, normochromic, and therefore erythrocytemorphology is particularly important to diagnosis. In contrast to exogenousiron deficiency anemias, the following phenomena are often observed,depending on the severity of the underlying condition:➤ Anisocytosis, i.e., strong variations in the size of the erythrocytes, beyondthe normal distribution. The result is that in almost every fieldview, some erythrocytes are either half the size or twice the size of theirneighbors.➤ Poikilocytosis, i.e., variations in the shape of the erythrocytes. In additionto the normal round shape, numbers of oval, or pear, or tear shapedcells are seen.➤ Polychromophilia, the third phenomenon in this series of nonspecificindicators of disturbed erythrocyte maturation, refers to light graybluestaining of the erythrocytes, indicating severely diminishedhemoglobin content of these immature cells.➤ Basophilic cytoplasmic stippling in erythrocytes is a sign of irregular regenerationand often occurs nonspecifically in secondary anemia.The reticulocyte count is usually reduced in infectious or toxic anemia, unlessthere is concomitant hemolysis or acute blood loss.Bone marrow analysis in secondary anemia usually shows reducederythropoiesis and granulopoiesis with a spectrum of immature cells (“infectious/toxicbone marrow”). The information is so nonspecific that usuallybone marrow aspiration is not performed. So long as all other laboratorymethods are employed, bone marrow cytology is very rarely neededin cases of hypochromic anemia.