Red cell disorders. Disorders of red cells can result in anemia or, less commonly, polycythemia (an increase in red cells also known as erythrocytosis ).
Anemia is defined as a reduction in the oxygen-transporting capacity of blood, which usually stems from a decrease in the red cell mass to subnormal levels
Anemia can result from bleeding, increased red cell destruction, or decreased red cell production. These mechanisms serve as one basis for classifying anemiasRED CELL DISORDERS
1- intrinsic (intracorpuscular) red cell defects, which are usually inherited
2- extrinsic (extracorpuscular) factors, which are usually acquired
- hyperplasia of erythroid progenitors expanded erythropoietic marrow may completely fill the intramedullary space of the skeleton:
1- inadequate dietary supply of nutrients: e.g. iron, folic acid, and vitamin B12.
2- anemias associated with bone marrow failure (aplastic anemia)
3- anemia of chronic disease (systemic inflammation)
4- bone marrow infiltration by tumor or inflammatory cells (myelophthisic anemia).
- (e.g., peptic ulcers, colonic cancer, hemorrhoids) and the female genital tract