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

146 Erythrocyte and Thrombocyte AbnormalitiesNormochromic Renal Anemia(Sometimes Hypochromic or Hyperchromic)Normochromic anemia should also suggest the possibility of renal insufficiency,which will always lead to anemia within a few weeks. In cases ofchronic renal insufficiency it is always present and may reach Hb values aslow as 6 g/dl. The anemia is caused by changes in the synthesis of erythropoietin,the hormone regulating erythropoiesis; measurement of serumerythropoietin is an important diagnostic tool. Erythrocyte life span is alsoslightly reduced.Apart from poikilocytosis, the blood cells are morphologically unremarkable.The reticulocyte counts often remain normal. The bone marrowdoes not show any significant characteristic changes, and therefore servesno diagnostic purpose in this situation.Anemias due to renal insufficiency are usually normochromic, but hypochromicor hyperchromic forms do occur. Hypochromic anemia is an indicatorof the reactive process that has led to the renal insufficiency (e.g.,pyelonephritis and glomerulonephritis), resulting in secondary hypochromicanemia. In addition, dialysis patients often develop iron deficiency.Chronic renal insufficiency can lead to folic acid deficiency, anddialysis therapy will reinforce this, explaining why hyperchromic anemiasalso occur in kidney disease.Bone Marrow AplasiaPure Red Cell Aplasia (PRCA, Erythroblastopenia)Erythroblastopenia in the sense of a purely aplastic condition in the redcell series is extremely rare. Diamond–Blackfan anemia (congenital hypoplasticanemia) is the congenital form of this disease. Acquired acute, transientinfections in adults and children are usually caused by virus infections(parvovirus B19). Chronic acquired erythroblastophthisis isfrequently associated with thymoma and has an autoimmune etiology.Anemia in pure erythroblastophthisis is normochromic without significantchanges in the CBC for white cells and thrombocytes. Naturally, thereticulocyte count is extremely low, close to zero.In all these anemias, the bone marrow shows well-developed granulopoiesisand megakaryopoiesis, but erythropoiesis is (more or less) entirelylacking.