Anemia

Anemia means literally lack of blood. In fact it is a reduction in the number of red blood cells, plasma, or packed red blood cells to a level that is lower than necessary for normal functioning. This is the result of the inability to replace lost cells or plasma volume at the rate they are being lost. The underlying cause for anemia may be one of several conditions.

Although blood cell levels are not lowered in sickle cell anemia, the blood cells may be nonfunctional at times, resulting in oxygen starvation of some body tissues.

There are many other kinds of anemias, though they are rarely seen. Those discussed are the most common types. Others include a form called spherocytosis, which, as the name implies, results in a spherical form of red blood cells resulting from an abnormality in the cell membrane; a similar form called elliptocytosis; and others resulting from decreased or abnormal hemoglobin production.