Pathology > Basic Hematology > Red Cell Disorders > Decreased RBC Production

Decreased RBC Production

Decreased RBC production may result from a defective stem cell (aplastic anemia) or may be due to lack of a necessary structural component (ie., iron) or lack of an enzyme (Vitamin B12) or enzyme abnormality (ie. Pb inhibition of 5'-pyrimidine nucleotidase).

If the genetic or acquired abnormality results in the destruction of erthrocytes in the marrow. This situation in which RBCs are generated, but do not reach the peripheral blood is termed ineffective erythropoiesis.


Anemias of Decreased Production

  • Aplastic
  • Fe deficiency
  • Sideroblastic
  • Anemia of chronic disease
  • Megaloblastic

The major causes of decreased RBC production may be summarized as resulting from decreased hemoglobin synthesis (Fe deficiency), decreased DNA synthesis (megaloblastic anemia), stem cell failure (aplastic anemia) or from unknown causes (anemia of chronic disease).




Decreased Hgb Synthesis

The finding of microcytosis and hypochromia implies decreased hemoglobin synthesis. The primary differential includes:

  • iron deficiency anemia
  • thalassemia
  • anemia of chronic disease
  • sideroblastic anemia

Based solely on incidence of disease - iron deficiency anemia and anemia of chronic disease are the two most likely considerations in the U.S. The incidence of thalassemia is increased in people from the regions of Africa, the Mediterranean, the Orient, and the Middle East.




Microcytic Anemia

Microcytic (small volume) RBCs with hypochromia (low Hgb content) indicate some inadequacy of structural substance, ie., not enough hemoglobin.

This inadequacy of structural matter may be due to:

1) an inadequate supply of nutrients (Fe deficiency)

2) a diverting of nutrients (? trapping by macrophages in anemia of chronic disease)

3) a failure of appropiate mechanisms (sideroblastic; Pb toxicity)

4) inadequate production quantity (thalassemia)


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