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
Anemia of chronic disease
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
iron deficiency anemia
anemia of chronic disease
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 (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
2) a diverting of nutrients (? trapping by macrophages in
anemia of chronic disease)
3) a failure of appropiate mechanisms (sideroblastic; Pb
Under no circumstances should you share any material downloaded from Student Source course websites with individuals outside the class. Under no circumstances should you repost material downloaded from Student Source to other websites. Some of our pages are restricted to UVa School of Medicine users and require an Oasis account for access.